rocket-tools/fsf-binutils-gdb.git - Unnamed repository; edit this file 'description' to name the repository.

Age	Commit message (Expand)	Author	Files	Lines
2005-05-13	Revert accidentally committed change.	Jim Blandy	1	-5/+5
2005-05-13	* gdb.base/call-ar-st.exp: Call 'untested' and return -1 instead of	Jim Blandy	5	-9/+19
2005-05-08	Add the fullname_syntax testsuite variable. This allows GDB to make sure	Bob Rossi	4	-3/+38
2005-05-04	* gdb.threads/linux-dp.exp: Check for --linux-gnu*.	Daniel Jacobowitz	2	-1/+5
2005-05-03	2004-05-02 Paul Gilliam <pgilliam@us.ibm.com>	Paul Gilliam	4	-2/+99
2005-05-02	* gdb.base/auxv.exp: Call 'untested' and return -1 instead of	Jim Blandy	2	-1/+7
2005-04-30	* gdb.threads/staticthreads.exp: Override signal to check for hppa.	Daniel Jacobowitz	2	-4/+16
2005-04-29	2005-04-29 Paul Gilliam <pgilliam@us.ibm.com>	Paul Gilliam	2	-42/+18
2005-04-29	2005-04-29 Paul Gilliam <pgilliam@us.ibm.com>	Paul Gilliam	2	-57/+23
2005-04-29	* gdb.asm/asm-source.exp: Add h8300 to supported targets.	Corinna Vinschen	3	-0/+59
2005-04-28	2005-04-19 Paul Gilliam <pgilliam@us.ibm.com>	Paul Gilliam	2	-65/+21
2005-04-28	2005-04-28 Paul Gilliam <pgilliam@us.ibm.com>	Paul Gilliam	2	-57/+18
2005-04-28	2005-04-28 Paul Gilliam <pgilliam@us.ibm.com>	Paul Gilliam	2	-30/+78
2005-04-27	2005-04-27 Paul Gilliam <pgilliam@us.ibm.com>	Paul Gilliam	2	-1/+11
2005-04-27	* ChangeLog: Correct some 2003-01-13 dates.	Daniel Jacobowitz	12	-13/+22
2005-04-14	* lib/gdb.exp (gdb_compile): Handle shlib=.	Daniel Jacobowitz	2	-0/+92
2005-04-12	2005-04-12 Paul Gilliam <pgilliam@us.ibm.com>	Paul Gilliam	2	-1/+5
2005-04-11	gdb/	Daniel Jacobowitz	7	-4/+17
2005-04-08	gdb/testsuite/	Daniel Jacobowitz	9	-176/+387
2005-04-06	test_compiler_info: Return compiler_info if no arguments are given.	Paul Gilliam	2	-0/+16
2005-04-01	* gdb.arch/altivec-abi.exp: Check for compiler and set	Paul Gilliam	3	-2/+38
2005-03-29	* c-valprint.c (c_value_print): Fix up some formatting. Use	Daniel Jacobowitz	3	-0/+89
2005-03-27	* gdb.base/bigcore.c (main): Add missing mode argument in open	Andreas Schwab	2	-1/+7
2005-03-25	* lib/mi-support.exp (mi_gdb_load): Use /tmp for gdbserver	Daniel Jacobowitz	3	-4/+10
2005-03-14	2005-03-14 Paul Brook <paul@codesourcery.com>	Paul Brook	2	-8/+8
2005-03-09	* gdb.dwarf2/dup-psym.S: New file.	Joel Brobecker	3	-0/+265
2005-03-08	* gdb.ada/exec_changed/first.adb: New file.	Joel Brobecker	4	-0/+101
2005-03-08	* ax-gdb.c (gen_expr): Add UNOP_PLUS case.	Nathan Sidwell	3	-2/+33
2005-03-08	* gdb.base/sigbpt.exp: Disable if gdb,nosignals.	Nathan Sidwell	10	-41/+80
2005-03-08	* gdb.asm/asm-source.exp: Add iq2000 case.	Corinna Vinschen	3	-0/+49
2005-03-07	2005-03-07 Manoj Iyer <manjo@austin.ibm.com>	Manoj Iyer	3	-1/+8
2005-03-07	* gdb.asm/alpha.inc, gdb.asm/frv.inc, gdb.asm/i386.inc,	Daniel Jacobowitz	14	-0/+26
2005-03-07	fix obvious problem with compiler.c and compiler.cc: for xlc, used 'regsub',	Paul Gilliam	2	-2/+2
2005-03-05	* gdb.cp/ovldbreak.exp: Adjust regular expression for recent	Mark Kettenis	2	-2/+6
2005-03-04	2004-03-03 Paul Gilliam <pgilliam@us.ibm.com>	Paul Gilliam	3	-0/+18
2005-02-24	* gdb.ada/fixed_points.exp: Create compilation object directory	Joel Brobecker	5	-0/+12
2005-02-15	* gdb.ada/packed_array/pa.adb: New file.	Joel Brobecker	3	-0/+78
2005-02-11	Fix my email address in last commit.	Mark Kettenis	1	-1/+1
2005-02-11	* gdb.dwarf2/dw2-intermix.exp, gdb.dwarf2/dw2-intermix.S: New	Mark Kettenis	3	-0/+258
2005-02-11	* gdb.dwarf2/dw2-basic.exp, gdb.dwarf2/dw2-intercu.exp: Run tests	Mark Kettenis	3	-6/+12
2005-02-10	From Ramana Radhakrishnan <ramana.radhakrishnan@codito.com>:	Daniel Jacobowitz	3	-0/+75
2005-02-09	* gdb.base/start.c: New file.	Joel Brobecker	3	-0/+90
2005-02-09	* gdb.ada/start/dummy.adb: New file.	Joel Brobecker	3	-0/+67
2005-02-09	* maint.exp: Raise timeout to give Cygwin targeted GDBs more time	Corinna Vinschen	2	-7/+56
2005-02-09	2005-02-09 Andreas Schwab <schwab@suse.de>	Andrew Cagney	2	-0/+51
2005-02-07	* gdb.base/interp.exp: Remove trailing n in gdb_test commands.	Mark Kettenis	2	-2/+6
2005-02-03	* gdb.ada/gnat_ada.gpr: New file.	Joel Brobecker	12	-17/+41
2005-02-02	New test for interpreter-exec command.	Nick Roberts	1	-0/+28
2005-02-02	* empty log message *	Nick Roberts	1	-0/+4
2005-01-24	Index: ChangeLog	Andrew Cagney	3	-0/+170

/* Support routines for Value Range Propagation (VRP). Copyright (C) 2005-2016 Free Software Foundation, Inc. Contributed by Diego Novillo <dnovillo@redhat.com>. This file is part of GCC. GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. GCC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GCC; see the file COPYING3. If not see <http://www.gnu.org/licenses/>. */ #include "config.h" #include "system.h" #include "coretypes.h" #include "backend.h" #include "insn-codes.h" #include "rtl.h" #include "tree.h" #include "gimple.h" #include "cfghooks.h" #include "tree-pass.h" #include "ssa.h" #include "optabs-tree.h" #include "gimple-pretty-print.h" #include "diagnostic-core.h" #include "flags.h" #include "fold-const.h" #include "stor-layout.h" #include "calls.h" #include "cfganal.h" #include "gimple-fold.h" #include "tree-eh.h" #include "gimple-iterator.h" #include "gimple-walk.h" #include "tree-cfg.h" #include "tree-ssa-loop-manip.h" #include "tree-ssa-loop-niter.h" #include "tree-ssa-loop.h" #include "tree-into-ssa.h" #include "tree-ssa.h" #include "intl.h" #include "cfgloop.h" #include "tree-scalar-evolution.h" #include "tree-ssa-propagate.h" #include "tree-chrec.h" #include "tree-ssa-threadupdate.h" #include "tree-ssa-scopedtables.h" #include "tree-ssa-threadedge.h" #include "omp-low.h" #include "target.h" #include "case-cfn-macros.h" #include "params.h" #include "alloc-pool.h" #include "domwalk.h" #include "tree-cfgcleanup.h" #define VR_INITIALIZER { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL } /* Allocation pools for tree-vrp allocations. */ static object_allocator<value_range> vrp_value_range_pool ("Tree VRP value ranges"); static bitmap_obstack vrp_equiv_obstack; /* Set of SSA names found live during the RPO traversal of the function for still active basic-blocks. */ static sbitmap *live; /* Return true if the SSA name NAME is live on the edge E. */ static bool live_on_edge (edge e, tree name) { return (live[e->dest->index] && bitmap_bit_p (live[e->dest->index], SSA_NAME_VERSION (name))); } /* Local functions. */ static int compare_values (tree val1, tree val2); static int compare_values_warnv (tree val1, tree val2, bool *); static tree vrp_evaluate_conditional_warnv_with_ops (enum tree_code, tree, tree, bool, bool *, bool *); /* Location information for ASSERT_EXPRs. Each instance of this structure describes an ASSERT_EXPR for an SSA name. Since a single SSA name may have more than one assertion associated with it, these locations are kept in a linked list attached to the corresponding SSA name. */ struct assert_locus { /* Basic block where the assertion would be inserted. */ basic_block bb; /* Some assertions need to be inserted on an edge (e.g., assertions generated by COND_EXPRs). In those cases, BB will be NULL. */ edge e; /* Pointer to the statement that generated this assertion. */ gimple_stmt_iterator si; /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */ enum tree_code comp_code; /* Value being compared against. */ tree val; /* Expression to compare. */ tree expr; /* Next node in the linked list. */ assert_locus *next; }; /* If bit I is present, it means that SSA name N_i has a list of assertions that should be inserted in the IL. */ static bitmap need_assert_for; /* Array of locations lists where to insert assertions. ASSERTS_FOR[I] holds a list of ASSERT_LOCUS_T nodes that describe where ASSERT_EXPRs for SSA name N_I should be inserted. */ static assert_locus **asserts_for; /* Value range array. After propagation, VR_VALUE[I] holds the range of values that SSA name N_I may take. */ static unsigned num_vr_values; static value_range **vr_value; static bool values_propagated; /* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the number of executable edges we saw the last time we visited the node. */ static int *vr_phi_edge_counts; struct switch_update { gswitch *stmt; tree vec; }; static vec<edge> to_remove_edges; static vec<switch_update> to_update_switch_stmts; /* Return the maximum value for TYPE. */ static inline tree vrp_val_max (const_tree type) { if (!INTEGRAL_TYPE_P (type)) return NULL_TREE; return TYPE_MAX_VALUE (type); } /* Return the minimum value for TYPE. */ static inline tree vrp_val_min (const_tree type) { if (!INTEGRAL_TYPE_P (type)) return NULL_TREE; return TYPE_MIN_VALUE (type); } /* Return whether VAL is equal to the maximum value of its type. This will be true for a positive overflow infinity. We can't do a simple equality comparison with TYPE_MAX_VALUE because C typedefs and Ada subtypes can produce types whose TYPE_MAX_VALUE is not == to the integer constant with the same value in the type. */ static inline bool vrp_val_is_max (const_tree val) { tree type_max = vrp_val_max (TREE_TYPE (val)); return (val == type_max || (type_max != NULL_TREE && operand_equal_p (val, type_max, 0))); } /* Return whether VAL is equal to the minimum value of its type. This will be true for a negative overflow infinity. */ static inline bool vrp_val_is_min (const_tree val) { tree type_min = vrp_val_min (TREE_TYPE (val)); return (val == type_min || (type_min != NULL_TREE && operand_equal_p (val, type_min, 0))); } /* Return whether TYPE should use an overflow infinity distinct from TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to represent a signed overflow during VRP computations. An infinity is distinct from a half-range, which will go from some number to TYPE_{MIN,MAX}_VALUE. */ static inline bool needs_overflow_infinity (const_tree type) { return INTEGRAL_TYPE_P (type) && !TYPE_OVERFLOW_WRAPS (type); } /* Return whether TYPE can support our overflow infinity representation: we use the TREE_OVERFLOW flag, which only exists for constants. If TYPE doesn't support this, we don't optimize cases which would require signed overflow--we drop them to VARYING. */ static inline bool supports_overflow_infinity (const_tree type) { tree min = vrp_val_min (type), max = vrp_val_max (type); gcc_checking_assert (needs_overflow_infinity (type)); return (min != NULL_TREE && CONSTANT_CLASS_P (min) && max != NULL_TREE && CONSTANT_CLASS_P (max)); } /* VAL is the maximum or minimum value of a type. Return a corresponding overflow infinity. */ static inline tree make_overflow_infinity (tree val) { gcc_checking_assert (val != NULL_TREE && CONSTANT_CLASS_P (val)); val = copy_node (val); TREE_OVERFLOW (val) = 1; return val; } /* Return a negative overflow infinity for TYPE. */ static inline tree negative_overflow_infinity (tree type) { gcc_checking_assert (supports_overflow_infinity (type)); return make_overflow_infinity (vrp_val_min (type)); } /* Return a positive overflow infinity for TYPE. */ static inline tree positive_overflow_infinity (tree type) { gcc_checking_assert (supports_overflow_infinity (type)); return make_overflow_infinity (vrp_val_max (type)); } /* Return whether VAL is a negative overflow infinity. */ static inline bool is_negative_overflow_infinity (const_tree val) { return (TREE_OVERFLOW_P (val) && needs_overflow_infinity (TREE_TYPE (val)) && vrp_val_is_min (val)); } /* Return whether VAL is a positive overflow infinity. */ static inline bool is_positive_overflow_infinity (const_tree val) { return (TREE_OVERFLOW_P (val) && needs_overflow_infinity (TREE_TYPE (val)) && vrp_val_is_max (val)); } /* Return whether VAL is a positive or negative overflow infinity. */ static inline bool is_overflow_infinity (const_tree val) { return (TREE_OVERFLOW_P (val) && needs_overflow_infinity (TREE_TYPE (val)) && (vrp_val_is_min (val) || vrp_val_is_max (val))); } /* Return whether STMT has a constant rhs that is_overflow_infinity. */ static inline bool stmt_overflow_infinity (gimple *stmt) { if (is_gimple_assign (stmt) && get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) == GIMPLE_SINGLE_RHS) return is_overflow_infinity (gimple_assign_rhs1 (stmt)); return false; } /* If VAL is now an overflow infinity, return VAL. Otherwise, return the same value with TREE_OVERFLOW clear. This can be used to avoid confusing a regular value with an overflow value. */ static inline tree avoid_overflow_infinity (tree val) { if (!is_overflow_infinity (val)) return val; if (vrp_val_is_max (val)) return vrp_val_max (TREE_TYPE (val)); else { gcc_checking_assert (vrp_val_is_min (val)); return vrp_val_min (TREE_TYPE (val)); } } /* Set value range VR to VR_UNDEFINED. */ static inline void set_value_range_to_undefined (value_range *vr) { vr->type = VR_UNDEFINED; vr->min = vr->max = NULL_TREE; if (vr->equiv) bitmap_clear (vr->equiv); } /* Set value range VR to VR_VARYING. */ static inline void set_value_range_to_varying (value_range *vr) { vr->type = VR_VARYING; vr->min = vr->max = NULL_TREE; if (vr->equiv) bitmap_clear (vr->equiv); } /* Set value range VR to {T, MIN, MAX, EQUIV}. */ static void set_value_range (value_range *vr, enum value_range_type t, tree min, tree max, bitmap equiv) { /* Check the validity of the range. */ if (flag_checking && (t == VR_RANGE || t == VR_ANTI_RANGE)) { int cmp; gcc_assert (min && max); gcc_assert ((!TREE_OVERFLOW_P (min) || is_overflow_infinity (min)) && (!TREE_OVERFLOW_P (max) || is_overflow_infinity (max))); if (INTEGRAL_TYPE_P (TREE_TYPE (min)) && t == VR_ANTI_RANGE) gcc_assert (!vrp_val_is_min (min) || !vrp_val_is_max (max)); cmp = compare_values (min, max); gcc_assert (cmp == 0 || cmp == -1 || cmp == -2); if (needs_overflow_infinity (TREE_TYPE (min))) gcc_assert (!is_overflow_infinity (min) || !is_overflow_infinity (max)); } if (flag_checking && (t == VR_UNDEFINED || t == VR_VARYING)) { gcc_assert (min == NULL_TREE && max == NULL_TREE); gcc_assert (equiv == NULL || bitmap_empty_p (equiv)); } vr->type = t; vr->min = min; vr->max = max; /* Since updating the equivalence set involves deep copying the bitmaps, only do it if absolutely necessary. */ if (vr->equiv == NULL && equiv != NULL) vr->equiv = BITMAP_ALLOC (&vrp_equiv_obstack); if (equiv != vr->equiv) { if (equiv && !bitmap_empty_p (equiv)) bitmap_copy (vr->equiv, equiv); else bitmap_clear (vr->equiv); } } /* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}. This means adjusting T, MIN and MAX representing the case of a wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX] as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges. In corner cases where MAX+1 or MIN-1 wraps this will fall back to varying. This routine exists to ease canonicalization in the case where we extract ranges from var + CST op limit. */ static void set_and_canonicalize_value_range (value_range *vr, enum value_range_type t, tree min, tree max, bitmap equiv) { /* Use the canonical setters for VR_UNDEFINED and VR_VARYING. */ if (t == VR_UNDEFINED) { set_value_range_to_undefined (vr); return; } else if (t == VR_VARYING) { set_value_range_to_varying (vr); return; } /* Nothing to canonicalize for symbolic ranges. */ if (TREE_CODE (min) != INTEGER_CST || TREE_CODE (max) != INTEGER_CST) { set_value_range (vr, t, min, max, equiv); return; } /* Wrong order for min and max, to swap them and the VR type we need to adjust them. */ if (tree_int_cst_lt (max, min)) { tree one, tmp; /* For one bit precision if max < min, then the swapped range covers all values, so for VR_RANGE it is varying and for VR_ANTI_RANGE empty range, so drop to varying as well. */ if (TYPE_PRECISION (TREE_TYPE (min)) == 1) { set_value_range_to_varying (vr); return; } one = build_int_cst (TREE_TYPE (min), 1); tmp = int_const_binop (PLUS_EXPR, max, one); max = int_const_binop (MINUS_EXPR, min, one); min = tmp; /* There's one corner case, if we had [C+1, C] before we now have that again. But this represents an empty value range, so drop to varying in this case. */ if (tree_int_cst_lt (max, min)) { set_value_range_to_varying (vr); return; } t = t == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE; } /* Anti-ranges that can be represented as ranges should be so. */ if (t == VR_ANTI_RANGE) { bool is_min = vrp_val_is_min (min); bool is_max = vrp_val_is_max (max); if (is_min && is_max) { /* We cannot deal with empty ranges, drop to varying. ??? This could be VR_UNDEFINED instead. */ set_value_range_to_varying (vr); return; } else if (TYPE_PRECISION (TREE_TYPE (min)) == 1 && (is_min || is_max)) { /* Non-empty boolean ranges can always be represented as a singleton range. */ if (is_min) min = max = vrp_val_max (TREE_TYPE (min)); else min = max = vrp_val_min (TREE_TYPE (min)); t = VR_RANGE; } else if (is_min /* As a special exception preserve non-null ranges. */ && !(TYPE_UNSIGNED (TREE_TYPE (min)) && integer_zerop (max))) { tree one = build_int_cst (TREE_TYPE (max), 1); min = int_const_binop (PLUS_EXPR, max, one); max = vrp_val_max (TREE_TYPE (max)); t = VR_RANGE; } else if (is_max) { tree one = build_int_cst (TREE_TYPE (min), 1); max = int_const_binop (MINUS_EXPR, min, one); min = vrp_val_min (TREE_TYPE (min)); t = VR_RANGE; } } /* Drop [-INF(OVF), +INF(OVF)] to varying. */ if (needs_overflow_infinity (TREE_TYPE (min)) && is_overflow_infinity (min) && is_overflow_infinity (max)) { set_value_range_to_varying (vr); return; } set_value_range (vr, t, min, max, equiv); } /* Copy value range FROM into value range TO. */ static inline void copy_value_range (value_range *to, value_range *from) { set_value_range (to, from->type, from->min, from->max, from->equiv); } /* Set value range VR to a single value. This function is only called with values we get from statements, and exists to clear the TREE_OVERFLOW flag so that we don't think we have an overflow infinity when we shouldn't. */ static inline void set_value_range_to_value (value_range *vr, tree val, bitmap equiv) { gcc_assert (is_gimple_min_invariant (val)); if (TREE_OVERFLOW_P (val)) val = drop_tree_overflow (val); set_value_range (vr, VR_RANGE, val, val, equiv); } /* Set value range VR to a non-negative range of type TYPE. OVERFLOW_INFINITY indicates whether to use an overflow infinity rather than TYPE_MAX_VALUE; this should be true if we determine that the range is nonnegative based on the assumption that signed overflow does not occur. */ static inline void set_value_range_to_nonnegative (value_range *vr, tree type, bool overflow_infinity) { tree zero; if (overflow_infinity && !supports_overflow_infinity (type)) { set_value_range_to_varying (vr); return; } zero = build_int_cst (type, 0); set_value_range (vr, VR_RANGE, zero, (overflow_infinity ? positive_overflow_infinity (type) : TYPE_MAX_VALUE (type)), vr->equiv); } /* Set value range VR to a non-NULL range of type TYPE. */ static inline void set_value_range_to_nonnull (value_range *vr, tree type) { tree zero = build_int_cst (type, 0); set_value_range (vr, VR_ANTI_RANGE, zero, zero, vr->equiv); } /* Set value range VR to a NULL range of type TYPE. */ static inline void set_value_range_to_null (value_range *vr, tree type) { set_value_range_to_value (vr, build_int_cst (type, 0), vr->equiv); } /* Set value range VR to a range of a truthvalue of type TYPE. */ static inline void set_value_range_to_truthvalue (value_range *vr, tree type) { if (TYPE_PRECISION (type) == 1) set_value_range_to_varying (vr); else set_value_range (vr, VR_RANGE, build_int_cst (type, 0), build_int_cst (type, 1), vr->equiv); } /* If abs (min) < abs (max), set VR to [-max, max], if abs (min) >= abs (max), set VR to [-min, min]. */ static void abs_extent_range (value_range *vr, tree min, tree max) { int cmp; gcc_assert (TREE_CODE (min) == INTEGER_CST); gcc_assert (TREE_CODE (max) == INTEGER_CST); gcc_assert (INTEGRAL_TYPE_P (TREE_TYPE (min))); gcc_assert (!TYPE_UNSIGNED (TREE_TYPE (min))); min = fold_unary (ABS_EXPR, TREE_TYPE (min), min); max = fold_unary (ABS_EXPR, TREE_TYPE (max), max); if (TREE_OVERFLOW (min) || TREE_OVERFLOW (max)) { set_value_range_to_varying (vr); return; } cmp = compare_values (min, max); if (cmp == -1) min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), max); else if (cmp == 0 || cmp == 1) { max = min; min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), min); } else { set_value_range_to_varying (vr); return; } set_and_canonicalize_value_range (vr, VR_RANGE, min, max, NULL); } /* Return value range information for VAR. If we have no values ranges recorded (ie, VRP is not running), then return NULL. Otherwise create an empty range if none existed for VAR. */ static value_range * get_value_range (const_tree var) { static const value_range vr_const_varying = { VR_VARYING, NULL_TREE, NULL_TREE, NULL }; value_range *vr; tree sym; unsigned ver = SSA_NAME_VERSION (var); /* If we have no recorded ranges, then return NULL. */ if (! vr_value) return NULL; /* If we query the range for a new SSA name return an unmodifiable VARYING. We should get here at most from the substitute-and-fold stage which will never try to change values. */ if (ver >= num_vr_values) return CONST_CAST (value_range *, &vr_const_varying); vr = vr_value[ver]; if (vr) return vr; /* After propagation finished do not allocate new value-ranges. */ if (values_propagated) return CONST_CAST (value_range *, &vr_const_varying); /* Create a default value range. */ vr_value[ver] = vr = vrp_value_range_pool.allocate (); memset (vr, 0, sizeof (*vr)); /* Defer allocating the equivalence set. */ vr->equiv = NULL; /* If VAR is a default definition of a parameter, the variable can take any value in VAR's type. */ if (SSA_NAME_IS_DEFAULT_DEF (var)) { sym = SSA_NAME_VAR (var); if (TREE_CODE (sym) == PARM_DECL) { /* Try to use the "nonnull" attribute to create ~[0, 0] anti-ranges for pointers. Note that this is only valid with default definitions of PARM_DECLs. */ if (POINTER_TYPE_P (TREE_TYPE (sym)) && (nonnull_arg_p (sym) || get_ptr_nonnull (var))) set_value_range_to_nonnull (vr, TREE_TYPE (sym)); else if (INTEGRAL_TYPE_P (TREE_TYPE (sym))) { wide_int min, max; value_range_type rtype = get_range_info (var, &min, &max); if (rtype == VR_RANGE || rtype == VR_ANTI_RANGE) set_value_range (vr, rtype, wide_int_to_tree (TREE_TYPE (var), min), wide_int_to_tree (TREE_TYPE (var), max), NULL); else set_value_range_to_varying (vr); } else set_value_range_to_varying (vr); } else if (TREE_CODE (sym) == RESULT_DECL && DECL_BY_REFERENCE (sym)) set_value_range_to_nonnull (vr, TREE_TYPE (sym)); } return vr; } /* Set value-ranges of all SSA names defined by STMT to varying. */ static void set_defs_to_varying (gimple *stmt) { ssa_op_iter i; tree def; FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF) { value_range *vr = get_value_range (def); /* Avoid writing to vr_const_varying get_value_range may return. */ if (vr->type != VR_VARYING) set_value_range_to_varying (vr); } } /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */ static inline bool vrp_operand_equal_p (const_tree val1, const_tree val2) { if (val1 == val2) return true; if (!val1 || !val2 || !operand_equal_p (val1, val2, 0)) return false; return is_overflow_infinity (val1) == is_overflow_infinity (val2); } /* Return true, if the bitmaps B1 and B2 are equal. */ static inline bool vrp_bitmap_equal_p (const_bitmap b1, const_bitmap b2) { return (b1 == b2 || ((!b1 || bitmap_empty_p (b1)) && (!b2 || bitmap_empty_p (b2))) || (b1 && b2 && bitmap_equal_p (b1, b2))); } /* Update the value range and equivalence set for variable VAR to NEW_VR. Return true if NEW_VR is different from VAR's previous value. NOTE: This function assumes that NEW_VR is a temporary value range object created for the sole purpose of updating VAR's range. The storage used by the equivalence set from NEW_VR will be freed by this function. Do not call update_value_range when NEW_VR is the range object associated with another SSA name. */ static inline bool update_value_range (const_tree var, value_range *new_vr) { value_range *old_vr; bool is_new; /* If there is a value-range on the SSA name from earlier analysis factor that in. */ if (INTEGRAL_TYPE_P (TREE_TYPE (var))) { wide_int min, max; value_range_type rtype = get_range_info (var, &min, &max); if (rtype == VR_RANGE || rtype == VR_ANTI_RANGE) { tree nr_min, nr_max; /* Range info on SSA names doesn't carry overflow information so make sure to preserve the overflow bit on the lattice. */ if (rtype == VR_RANGE && needs_overflow_infinity (TREE_TYPE (var)) && (new_vr->type == VR_VARYING || (new_vr->type == VR_RANGE && is_negative_overflow_infinity (new_vr->min))) && wi::eq_p (vrp_val_min (TREE_TYPE (var)), min)) nr_min = negative_overflow_infinity (TREE_TYPE (var)); else nr_min = wide_int_to_tree (TREE_TYPE (var), min); if (rtype == VR_RANGE && needs_overflow_infinity (TREE_TYPE (var)) && (new_vr->type == VR_VARYING || (new_vr->type == VR_RANGE && is_positive_overflow_infinity (new_vr->max))) && wi::eq_p (vrp_val_max (TREE_TYPE (var)), max)) nr_max = positive_overflow_infinity (TREE_TYPE (var)); else nr_max = wide_int_to_tree (TREE_TYPE (var), max); value_range nr = VR_INITIALIZER; set_and_canonicalize_value_range (&nr, rtype, nr_min, nr_max, NULL); vrp_intersect_ranges (new_vr, &nr); } } /* Update the value range, if necessary. */ old_vr = get_value_range (var); is_new = old_vr->type != new_vr->type || !vrp_operand_equal_p (old_vr->min, new_vr->min) || !vrp_operand_equal_p (old_vr->max, new_vr->max) || !vrp_bitmap_equal_p (old_vr->equiv, new_vr->equiv); if (is_new) { /* Do not allow transitions up the lattice. The following is slightly more awkward than just new_vr->type < old_vr->type because VR_RANGE and VR_ANTI_RANGE need to be considered the same. We may not have is_new when transitioning to UNDEFINED. If old_vr->type is VARYING, we shouldn't be called. */ if (new_vr->type == VR_UNDEFINED) { BITMAP_FREE (new_vr->equiv); set_value_range_to_varying (old_vr); set_value_range_to_varying (new_vr); return true; } else set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max, new_vr->equiv); } BITMAP_FREE (new_vr->equiv); return is_new; } /* Add VAR and VAR's equivalence set to EQUIV. This is the central point where equivalence processing can be turned on/off. */ static void add_equivalence (bitmap *equiv, const_tree var) { unsigned ver = SSA_NAME_VERSION (var); value_range *vr = get_value_range (var); if (*equiv == NULL) *equiv = BITMAP_ALLOC (&vrp_equiv_obstack); bitmap_set_bit (*equiv, ver); if (vr && vr->equiv) bitmap_ior_into (*equiv, vr->equiv); } /* Return true if VR is ~[0, 0]. */ static inline bool range_is_nonnull (value_range *vr) { return vr->type == VR_ANTI_RANGE && integer_zerop (vr->min) && integer_zerop (vr->max); } /* Return true if VR is [0, 0]. */ static inline bool range_is_null (value_range *vr) { return vr->type == VR_RANGE && integer_zerop (vr->min) && integer_zerop (vr->max); } /* Return true if max and min of VR are INTEGER_CST. It's not necessary a singleton. */ static inline bool range_int_cst_p (value_range *vr) { return (vr->type == VR_RANGE && TREE_CODE (vr->max) == INTEGER_CST && TREE_CODE (vr->min) == INTEGER_CST); } /* Return true if VR is a INTEGER_CST singleton. */ static inline bool range_int_cst_singleton_p (value_range *vr) { return (range_int_cst_p (vr) && !is_overflow_infinity (vr->min) && !is_overflow_infinity (vr->max) && tree_int_cst_equal (vr->min, vr->max)); } /* Return true if value range VR involves at least one symbol. */ static inline bool symbolic_range_p (value_range *vr) { return (!is_gimple_min_invariant (vr->min) || !is_gimple_min_invariant (vr->max)); } /* Return the single symbol (an SSA_NAME) contained in T if any, or NULL_TREE otherwise. We only handle additive operations and set NEG to true if the symbol is negated and INV to the invariant part, if any. */ static tree get_single_symbol (tree t, bool *neg, tree *inv) { bool neg_; tree inv_; *inv = NULL_TREE; *neg = false; if (TREE_CODE (t) == PLUS_EXPR || TREE_CODE (t) == POINTER_PLUS_EXPR || TREE_CODE (t) == MINUS_EXPR) { if (is_gimple_min_invariant (TREE_OPERAND (t, 0))) { neg_ = (TREE_CODE (t) == MINUS_EXPR); inv_ = TREE_OPERAND (t, 0); t = TREE_OPERAND (t, 1); } else if (is_gimple_min_invariant (TREE_OPERAND (t, 1))) { neg_ = false; inv_ = TREE_OPERAND (t, 1); t = TREE_OPERAND (t, 0); } else return NULL_TREE; } else { neg_ = false; inv_ = NULL_TREE; } if (TREE_CODE (t) == NEGATE_EXPR) { t = TREE_OPERAND (t, 0); neg_ = !neg_; } if (TREE_CODE (t) != SSA_NAME) return NULL_TREE; *neg = neg_; *inv = inv_; return t; } /* The reverse operation: build a symbolic expression with TYPE from symbol SYM, negated according to NEG, and invariant INV. */ static tree build_symbolic_expr (tree type, tree sym, bool neg, tree inv) { const bool pointer_p = POINTER_TYPE_P (type); tree t = sym; if (neg) t = build1 (NEGATE_EXPR, type, t); if (integer_zerop (inv)) return t; return build2 (pointer_p ? POINTER_PLUS_EXPR : PLUS_EXPR, type, t, inv); } /* Return true if value range VR involves exactly one symbol SYM. */ static bool symbolic_range_based_on_p (value_range *vr, const_tree sym) { bool neg, min_has_symbol, max_has_symbol; tree inv; if (is_gimple_min_invariant (vr->min)) min_has_symbol = false; else if (get_single_symbol (vr->min, &neg, &inv) == sym) min_has_symbol = true; else return false; if (is_gimple_min_invariant (vr->max)) max_has_symbol = false; else if (get_single_symbol (vr->max, &neg, &inv) == sym) max_has_symbol = true; else return false; return (min_has_symbol || max_has_symbol); } /* Return true if value range VR uses an overflow infinity. */ static inline bool overflow_infinity_range_p (value_range *vr) { return (vr->type == VR_RANGE && (is_overflow_infinity (vr->min) || is_overflow_infinity (vr->max))); } /* Return false if we can not make a valid comparison based on VR; this will be the case if it uses an overflow infinity and overflow is not undefined (i.e., -fno-strict-overflow is in effect). Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR uses an overflow infinity. */ static bool usable_range_p (value_range *vr, bool *strict_overflow_p) { gcc_assert (vr->type == VR_RANGE); if (is_overflow_infinity (vr->min)) { *strict_overflow_p = true; if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->min))) return false; } if (is_overflow_infinity (vr->max)) { *strict_overflow_p = true; if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->max))) return false; } return true; } /* Return true if the result of assignment STMT is know to be non-zero. If the return value is based on the assumption that signed overflow is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change *STRICT_OVERFLOW_P.*/ static bool gimple_assign_nonzero_warnv_p (gimple *stmt, bool *strict_overflow_p) { enum tree_code code = gimple_assign_rhs_code (stmt); switch (get_gimple_rhs_class (code)) { case GIMPLE_UNARY_RHS: return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt), gimple_expr_type (stmt), gimple_assign_rhs1 (stmt), strict_overflow_p); case GIMPLE_BINARY_RHS: return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt), gimple_expr_type (stmt), gimple_assign_rhs1 (stmt), gimple_assign_rhs2 (stmt), strict_overflow_p); case GIMPLE_TERNARY_RHS: return false; case GIMPLE_SINGLE_RHS: return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt), strict_overflow_p); case GIMPLE_INVALID_RHS: gcc_unreachable (); default: gcc_unreachable (); } } /* Return true if STMT is known to compute a non-zero value. If the return value is based on the assumption that signed overflow is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change *STRICT_OVERFLOW_P.*/ static bool gimple_stmt_nonzero_warnv_p (gimple *stmt, bool *strict_overflow_p) { switch (gimple_code (stmt)) { case GIMPLE_ASSIGN: return gimple_assign_nonzero_warnv_p (stmt, strict_overflow_p); case GIMPLE_CALL: { tree fndecl = gimple_call_fndecl (stmt); if (!fndecl) return false; if (flag_delete_null_pointer_checks && !flag_check_new && DECL_IS_OPERATOR_NEW (fndecl) && !TREE_NOTHROW (fndecl)) return true; /* References are always non-NULL. */ if (flag_delete_null_pointer_checks && TREE_CODE (TREE_TYPE (fndecl)) == REFERENCE_TYPE) return true; if (flag_delete_null_pointer_checks && lookup_attribute ("returns_nonnull", TYPE_ATTRIBUTES (gimple_call_fntype (stmt)))) return true; gcall *call_stmt = as_a<gcall *> (stmt); unsigned rf = gimple_call_return_flags (call_stmt); if (rf & ERF_RETURNS_ARG) { unsigned argnum = rf & ERF_RETURN_ARG_MASK; if (argnum < gimple_call_num_args (call_stmt)) { tree arg = gimple_call_arg (call_stmt, argnum); if (SSA_VAR_P (arg) && infer_nonnull_range_by_attribute (stmt, arg)) return true; } } return gimple_alloca_call_p (stmt); } default: gcc_unreachable (); } } /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges obtained so far. */ static bool vrp_stmt_computes_nonzero (gimple *stmt, bool *strict_overflow_p) { if (gimple_stmt_nonzero_warnv_p (stmt, strict_overflow_p)) return true; /* If we have an expression of the form &X->a, then the expression is nonnull if X is nonnull. */ if (is_gimple_assign (stmt) && gimple_assign_rhs_code (stmt) == ADDR_EXPR) { tree expr = gimple_assign_rhs1 (stmt); tree base = get_base_address (TREE_OPERAND (expr, 0)); if (base != NULL_TREE && TREE_CODE (base) == MEM_REF && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME) { value_range *vr = get_value_range (TREE_OPERAND (base, 0)); if (range_is_nonnull (vr)) return true; } } return false; } /* Returns true if EXPR is a valid value (as expected by compare_values) -- a gimple invariant, or SSA_NAME +- CST. */ static bool valid_value_p (tree expr) { if (TREE_CODE (expr) == SSA_NAME) return true; if (TREE_CODE (expr) == PLUS_EXPR || TREE_CODE (expr) == MINUS_EXPR) return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST); return is_gimple_min_invariant (expr); } /* Return 1 if VAL < VAL2 0 if !(VAL < VAL2) -2 if those are incomparable. */ static inline int operand_less_p (tree val, tree val2) { /* LT is folded faster than GE and others. Inline the common case. */ if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST) { if (! is_positive_overflow_infinity (val2)) return tree_int_cst_lt (val, val2); } else { tree tcmp; fold_defer_overflow_warnings (); tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2); fold_undefer_and_ignore_overflow_warnings (); if (!tcmp || TREE_CODE (tcmp) != INTEGER_CST) return -2; if (!integer_zerop (tcmp)) return 1; } /* val >= val2, not considering overflow infinity. */ if (is_negative_overflow_infinity (val)) return is_negative_overflow_infinity (val2) ? 0 : 1; else if (is_positive_overflow_infinity (val2)) return is_positive_overflow_infinity (val) ? 0 : 1; return 0; } /* Compare two values VAL1 and VAL2. Return -2 if VAL1 and VAL2 cannot be compared at compile-time, -1 if VAL1 < VAL2, 0 if VAL1 == VAL2, +1 if VAL1 > VAL2, and +2 if VAL1 != VAL2 This is similar to tree_int_cst_compare but supports pointer values and values that cannot be compared at compile time. If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to true if the return value is only valid if we assume that signed overflow is undefined. */ static int compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p) { if (val1 == val2) return 0; /* Below we rely on the fact that VAL1 and VAL2 are both pointers or both integers. */ gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1)) == POINTER_TYPE_P (TREE_TYPE (val2))); /* Convert the two values into the same type. This is needed because sizetype causes sign extension even for unsigned types. */ val2 = fold_convert (TREE_TYPE (val1), val2); STRIP_USELESS_TYPE_CONVERSION (val2); const bool overflow_undefined = INTEGRAL_TYPE_P (TREE_TYPE (val1)) && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1)); tree inv1, inv2; bool neg1, neg2; tree sym1 = get_single_symbol (val1, &neg1, &inv1); tree sym2 = get_single_symbol (val2, &neg2, &inv2); /* If VAL1 and VAL2 are of the form '[-]NAME [+ CST]', return -1 or +1 accordingly. If VAL1 and VAL2 don't use the same name, return -2. */ if (sym1 && sym2) { /* Both values must use the same name with the same sign. */ if (sym1 != sym2 || neg1 != neg2) return -2; /* [-]NAME + CST == [-]NAME + CST. */ if (inv1 == inv2) return 0; /* If overflow is defined we cannot simplify more. */ if (!overflow_undefined) return -2; if (strict_overflow_p != NULL && (!inv1 || !TREE_NO_WARNING (val1)) && (!inv2 || !TREE_NO_WARNING (val2))) *strict_overflow_p = true; if (!inv1) inv1 = build_int_cst (TREE_TYPE (val1), 0); if (!inv2) inv2 = build_int_cst (TREE_TYPE (val2), 0); return compare_values_warnv (inv1, inv2, strict_overflow_p); } const bool cst1 = is_gimple_min_invariant (val1); const bool cst2 = is_gimple_min_invariant (val2); /* If one is of the form '[-]NAME + CST' and the other is constant, then it might be possible to say something depending on the constants. */ if ((sym1 && inv1 && cst2) || (sym2 && inv2 && cst1)) { if (!overflow_undefined) return -2; if (strict_overflow_p != NULL && (!sym1 || !TREE_NO_WARNING (val1)) && (!sym2 || !TREE_NO_WARNING (val2))) *strict_overflow_p = true; const signop sgn = TYPE_SIGN (TREE_TYPE (val1)); tree cst = cst1 ? val1 : val2; tree inv = cst1 ? inv2 : inv1; /* Compute the difference between the constants. If it overflows or underflows, this means that we can trivially compare the NAME with it and, consequently, the two values with each other. */ wide_int diff = wi::sub (cst, inv); if (wi::cmp (0, inv, sgn) != wi::cmp (diff, cst, sgn)) { const int res = wi::cmp (cst, inv, sgn); return cst1 ? res : -res; } return -2; } /* We cannot say anything more for non-constants. */ if (!cst1 || !cst2) return -2; if (!POINTER_TYPE_P (TREE_TYPE (val1))) { /* We cannot compare overflowed values, except for overflow infinities. */ if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2)) { if (strict_overflow_p != NULL) *strict_overflow_p = true; if (is_negative_overflow_infinity (val1)) return is_negative_overflow_infinity (val2) ? 0 : -1; else if (is_negative_overflow_infinity (val2)) return 1; else if (is_positive_overflow_infinity (val1)) return is_positive_overflow_infinity (val2) ? 0 : 1; else if (is_positive_overflow_infinity (val2)) return -1; return -2; } return tree_int_cst_compare (val1, val2); } else { tree t; /* First see if VAL1 and VAL2 are not the same. */ if (val1 == val2 || operand_equal_p (val1, val2, 0)) return 0; /* If VAL1 is a lower address than VAL2, return -1. */ if (operand_less_p (val1, val2) == 1) return -1; /* If VAL1 is a higher address than VAL2, return +1. */ if (operand_less_p (val2, val1) == 1) return 1; /* If VAL1 is different than VAL2, return +2. For integer constants we either have already returned -1 or 1 or they are equivalent. We still might succeed in proving something about non-trivial operands. */ if (TREE_CODE (val1) != INTEGER_CST || TREE_CODE (val2) != INTEGER_CST) { t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2); if (t && integer_onep (t)) return 2; } return -2; } } /* Compare values like compare_values_warnv, but treat comparisons of nonconstants which rely on undefined overflow as incomparable. */ static int compare_values (tree val1, tree val2) { bool sop; int ret; sop = false; ret = compare_values_warnv (val1, val2, &sop); if (sop && (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2))) ret = -2; return ret; } /* Return 1 if VAL is inside value range MIN <= VAL <= MAX, 0 if VAL is not inside [MIN, MAX], -2 if we cannot tell either way. Benchmark compile/20001226-1.c compilation time after changing this function. */ static inline int value_inside_range (tree val, tree min, tree max) { int cmp1, cmp2; cmp1 = operand_less_p (val, min); if (cmp1 == -2) return -2; if (cmp1 == 1) return 0; cmp2 = operand_less_p (max, val); if (cmp2 == -2) return -2; return !cmp2; } /* Return true if value ranges VR0 and VR1 have a non-empty intersection. Benchmark compile/20001226-1.c compilation time after changing this function. */ static inline bool value_ranges_intersect_p (value_range *vr0, value_range *vr1) { /* The value ranges do not intersect if the maximum of the first range is less than the minimum of the second range or vice versa. When those relations are unknown, we can't do any better. */ if (operand_less_p (vr0->max, vr1->min) != 0) return false; if (operand_less_p (vr1->max, vr0->min) != 0) return false; return true; } /* Return 1 if [MIN, MAX] includes the value zero, 0 if it does not include the value zero, -2 if we cannot tell. */ static inline int range_includes_zero_p (tree min, tree max) { tree zero = build_int_cst (TREE_TYPE (min), 0); return value_inside_range (zero, min, max); } /* Return true if *VR is know to only contain nonnegative values. */ static inline bool value_range_nonnegative_p (value_range *vr) { /* Testing for VR_ANTI_RANGE is not useful here as any anti-range which would return a useful value should be encoded as a VR_RANGE. */ if (vr->type == VR_RANGE) { int result = compare_values (vr->min, integer_zero_node); return (result == 0 || result == 1); } return false; } /* If *VR has a value rante that is a single constant value return that, otherwise return NULL_TREE. */ static tree value_range_constant_singleton (value_range *vr) { if (vr->type == VR_RANGE && vrp_operand_equal_p (vr->min, vr->max) && is_gimple_min_invariant (vr->min)) return vr->min; return NULL_TREE; } /* If OP has a value range with a single constant value return that, otherwise return NULL_TREE. This returns OP itself if OP is a constant. */ static tree op_with_constant_singleton_value_range (tree op) { if (is_gimple_min_invariant (op)) return op; if (TREE_CODE (op) != SSA_NAME) return NULL_TREE; return value_range_constant_singleton (get_value_range (op)); } /* Return true if op is in a boolean [0, 1] value-range. */ static bool op_with_boolean_value_range_p (tree op) { value_range *vr; if (TYPE_PRECISION (TREE_TYPE (op)) == 1) return true; if (integer_zerop (op) || integer_onep (op)) return true; if (TREE_CODE (op) != SSA_NAME) return false; vr = get_value_range (op); return (vr->type == VR_RANGE && integer_zerop (vr->min) && integer_onep (vr->max)); } /* Extract value range information for VAR when (OP COND_CODE LIMIT) is true and store it in *VR_P. */ static void extract_range_for_var_from_comparison_expr (tree var, enum tree_code cond_code, tree op, tree limit, value_range *vr_p) { tree min, max, type; value_range *limit_vr; limit = avoid_overflow_infinity (limit); type = TREE_TYPE (var); gcc_assert (limit != var); /* For pointer arithmetic, we only keep track of pointer equality and inequality. */ if (POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR) { set_value_range_to_varying (vr_p); return; } /* If LIMIT is another SSA name and LIMIT has a range of its own, try to use LIMIT's range to avoid creating symbolic ranges unnecessarily. */ limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL; /* LIMIT's range is only interesting if it has any useful information. */ if (! limit_vr || limit_vr->type == VR_UNDEFINED || limit_vr->type == VR_VARYING || (symbolic_range_p (limit_vr) && ! (limit_vr->type == VR_RANGE && (limit_vr->min == limit_vr->max || operand_equal_p (limit_vr->min, limit_vr->max, 0))))) limit_vr = NULL; /* Initially, the new range has the same set of equivalences of VAR's range. This will be revised before returning the final value. Since assertions may be chained via mutually exclusive predicates, we will need to trim the set of equivalences before we are done. */ gcc_assert (vr_p->equiv == NULL); add_equivalence (&vr_p->equiv, var); /* Extract a new range based on the asserted comparison for VAR and LIMIT's value range. Notice that if LIMIT has an anti-range, we will only use it for equality comparisons (EQ_EXPR). For any other kind of assertion, we cannot derive a range from LIMIT's anti-range that can be used to describe the new range. For instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10], then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is no single range for x_2 that could describe LE_EXPR, so we might as well build the range [b_4, +INF] for it. One special case we handle is extracting a range from a range test encoded as (unsigned)var + CST <= limit. */ if (TREE_CODE (op) == NOP_EXPR || TREE_CODE (op) == PLUS_EXPR) { if (TREE_CODE (op) == PLUS_EXPR) { min = fold_build1 (NEGATE_EXPR, TREE_TYPE (TREE_OPERAND (op, 1)), TREE_OPERAND (op, 1)); max = int_const_binop (PLUS_EXPR, limit, min); op = TREE_OPERAND (op, 0); } else { min = build_int_cst (TREE_TYPE (var), 0); max = limit; } /* Make sure to not set TREE_OVERFLOW on the final type conversion. We are willingly interpreting large positive unsigned values as negative signed values here. */ min = force_fit_type (TREE_TYPE (var), wi::to_widest (min), 0, false); max = force_fit_type (TREE_TYPE (var), wi::to_widest (max), 0, false); /* We can transform a max, min range to an anti-range or vice-versa. Use set_and_canonicalize_value_range which does this for us. */ if (cond_code == LE_EXPR) set_and_canonicalize_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv); else if (cond_code == GT_EXPR) set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE, min, max, vr_p->equiv); else gcc_unreachable (); } else if (cond_code == EQ_EXPR) { enum value_range_type range_type; if (limit_vr) { range_type = limit_vr->type; min = limit_vr->min; max = limit_vr->max; } else { range_type = VR_RANGE; min = limit; max = limit; } set_value_range (vr_p, range_type, min, max, vr_p->equiv); /* When asserting the equality VAR == LIMIT and LIMIT is another SSA name, the new range will also inherit the equivalence set from LIMIT. */ if (TREE_CODE (limit) == SSA_NAME) add_equivalence (&vr_p->equiv, limit); } else if (cond_code == NE_EXPR) { /* As described above, when LIMIT's range is an anti-range and this assertion is an inequality (NE_EXPR), then we cannot derive anything from the anti-range. For instance, if LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does not imply that VAR's range is [0, 0]. So, in the case of anti-ranges, we just assert the inequality using LIMIT and not its anti-range. If LIMIT_VR is a range, we can only use it to build a new anti-range if LIMIT_VR is a single-valued range. For instance, if LIMIT_VR is [0, 1], the predicate VAR != [0, 1] does not mean that VAR's range is ~[0, 1]. Rather, it means that for value 0 VAR should be ~[0, 0] and for value 1, VAR should be ~[1, 1]. We cannot represent these ranges. The only situation in which we can build a valid anti-range is when LIMIT_VR is a single-valued range (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case, build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */ if (limit_vr && limit_vr->type == VR_RANGE && compare_values (limit_vr->min, limit_vr->max) == 0) { min = limit_vr->min; max = limit_vr->max; } else { /* In any other case, we cannot use LIMIT's range to build a valid anti-range. */ min = max = limit; } /* If MIN and MAX cover the whole range for their type, then just use the original LIMIT. */ if (INTEGRAL_TYPE_P (type) && vrp_val_is_min (min) && vrp_val_is_max (max)) min = max = limit; set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE, min, max, vr_p->equiv); } else if (cond_code == LE_EXPR || cond_code == LT_EXPR) { min = TYPE_MIN_VALUE (type); if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE) max = limit; else { /* If LIMIT_VR is of the form [N1, N2], we need to build the range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for LT_EXPR. */ max = limit_vr->max; } /* If the maximum value forces us to be out of bounds, simply punt. It would be pointless to try and do anything more since this all should be optimized away above us. */ if ((cond_code == LT_EXPR && compare_values (max, min) == 0) || is_overflow_infinity (max)) set_value_range_to_varying (vr_p); else { /* For LT_EXPR, we create the range [MIN, MAX - 1]. */ if (cond_code == LT_EXPR) { if (TYPE_PRECISION (TREE_TYPE (max)) == 1 && !TYPE_UNSIGNED (TREE_TYPE (max))) max = fold_build2 (PLUS_EXPR, TREE_TYPE (max), max, build_int_cst (TREE_TYPE (max), -1)); else max = fold_build2 (MINUS_EXPR, TREE_TYPE (max), max, build_int_cst (TREE_TYPE (max), 1)); if (EXPR_P (max)) TREE_NO_WARNING (max) = 1; } set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv); } } else if (cond_code == GE_EXPR || cond_code == GT_EXPR) { max = TYPE_MAX_VALUE (type); if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE) min = limit; else { /* If LIMIT_VR is of the form [N1, N2], we need to build the range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for GT_EXPR. */ min = limit_vr->min; } /* If the minimum value forces us to be out of bounds, simply punt. It would be pointless to try and do anything more since this all should be optimized away above us. */ if ((cond_code == GT_EXPR && compare_values (min, max) == 0) || is_overflow_infinity (min)) set_value_range_to_varying (vr_p); else { /* For GT_EXPR, we create the range [MIN + 1, MAX]. */ if (cond_code == GT_EXPR) { if (TYPE_PRECISION (TREE_TYPE (min)) == 1 && !TYPE_UNSIGNED (TREE_TYPE (min))) min = fold_build2 (MINUS_EXPR, TREE_TYPE (min), min, build_int_cst (TREE_TYPE (min), -1)); else min = fold_build2 (PLUS_EXPR, TREE_TYPE (min), min, build_int_cst (TREE_TYPE (min), 1)); if (EXPR_P (min)) TREE_NO_WARNING (min) = 1; } set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv); } } else gcc_unreachable (); /* Finally intersect the new range with what we already know about var. */ vrp_intersect_ranges (vr_p, get_value_range (var)); } /* Extract value range information from an ASSERT_EXPR EXPR and store it in *VR_P. */ static void extract_range_from_assert (value_range *vr_p, tree expr) { tree var = ASSERT_EXPR_VAR (expr); tree cond = ASSERT_EXPR_COND (expr); tree limit, op; enum tree_code cond_code; gcc_assert (COMPARISON_CLASS_P (cond)); /* Find VAR in the ASSERT_EXPR conditional. */ if (var == TREE_OPERAND (cond, 0) || TREE_CODE (TREE_OPERAND (cond, 0)) == PLUS_EXPR || TREE_CODE (TREE_OPERAND (cond, 0)) == NOP_EXPR) { /* If the predicate is of the form VAR COMP LIMIT, then we just take LIMIT from the RHS and use the same comparison code. */ cond_code = TREE_CODE (cond); limit = TREE_OPERAND (cond, 1); op = TREE_OPERAND (cond, 0); } else { /* If the predicate is of the form LIMIT COMP VAR, then we need to flip around the comparison code to create the proper range for VAR. */ cond_code = swap_tree_comparison (TREE_CODE (cond)); limit = TREE_OPERAND (cond, 0); op = TREE_OPERAND (cond, 1); } extract_range_for_var_from_comparison_expr (var, cond_code, op, limit, vr_p); } /* Extract range information from SSA name VAR and store it in VR. If VAR has an interesting range, use it. Otherwise, create the range [VAR, VAR] and return it. This is useful in situations where we may have conditionals testing values of VARYING names. For instance, x_3 = y_5; if (x_3 > y_5) ... Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is always false. */ static void extract_range_from_ssa_name (value_range *vr, tree var) { value_range *var_vr = get_value_range (var); if (var_vr->type != VR_VARYING) copy_value_range (vr, var_vr); else set_value_range (vr, VR_RANGE, var, var, NULL); add_equivalence (&vr->equiv, var); } /* Wrapper around int_const_binop. If the operation overflows and we are not using wrapping arithmetic, then adjust the result to be -INF or +INF depending on CODE, VAL1 and VAL2. This can return NULL_TREE if we need to use an overflow infinity representation but the type does not support it. */ static tree vrp_int_const_binop (enum tree_code code, tree val1, tree val2) { tree res; res = int_const_binop (code, val1, val2); /* If we are using unsigned arithmetic, operate symbolically on -INF and +INF as int_const_binop only handles signed overflow. */ if (TYPE_UNSIGNED (TREE_TYPE (val1))) { int checkz = compare_values (res, val1); bool overflow = false; /* Ensure that res = val1 [+*] val2 >= val1 or that res = val1 - val2 <= val1. */ if ((code == PLUS_EXPR && !(checkz == 1 || checkz == 0)) || (code == MINUS_EXPR && !(checkz == 0 || checkz == -1))) { overflow = true; } /* Checking for multiplication overflow is done by dividing the output of the multiplication by the first input of the multiplication. If the result of that division operation is not equal to the second input of the multiplication, then the multiplication overflowed. */ else if (code == MULT_EXPR && !integer_zerop (val1)) { tree tmp = int_const_binop (TRUNC_DIV_EXPR, res, val1); int check = compare_values (tmp, val2); if (check != 0) overflow = true; } if (overflow) { res = copy_node (res); TREE_OVERFLOW (res) = 1; } } else if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1))) /* If the singed operation wraps then int_const_binop has done everything we want. */ ; /* Signed division of -1/0 overflows and by the time it gets here returns NULL_TREE. */ else if (!res) return NULL_TREE; else if ((TREE_OVERFLOW (res) && !TREE_OVERFLOW (val1) && !TREE_OVERFLOW (val2)) || is_overflow_infinity (val1) || is_overflow_infinity (val2)) { /* If the operation overflowed but neither VAL1 nor VAL2 are overflown, return -INF or +INF depending on the operation and the combination of signs of the operands. */ int sgn1 = tree_int_cst_sgn (val1); int sgn2 = tree_int_cst_sgn (val2); if (needs_overflow_infinity (TREE_TYPE (res)) && !supports_overflow_infinity (TREE_TYPE (res))) return NULL_TREE; /* We have to punt on adding infinities of different signs, since we can't tell what the sign of the result should be. Likewise for subtracting infinities of the same sign. */ if (((code == PLUS_EXPR && sgn1 != sgn2) || (code == MINUS_EXPR && sgn1 == sgn2)) && is_overflow_infinity (val1) && is_overflow_infinity (val2)) return NULL_TREE; /* Don't try to handle division or shifting of infinities. */ if ((code == TRUNC_DIV_EXPR || code == FLOOR_DIV_EXPR || code == CEIL_DIV_EXPR || code == EXACT_DIV_EXPR || code == ROUND_DIV_EXPR || code == RSHIFT_EXPR) && (is_overflow_infinity (val1) || is_overflow_infinity (val2))) return NULL_TREE; /* Notice that we only need to handle the restricted set of operations handled by extract_range_from_binary_expr. Among them, only multiplication, addition and subtraction can yield overflow without overflown operands because we are working with integral types only... except in the case VAL1 = -INF and VAL2 = -1 which overflows to +INF for division too. */ /* For multiplication, the sign of the overflow is given by the comparison of the signs of the operands. */ if ((code == MULT_EXPR && sgn1 == sgn2) /* For addition, the operands must be of the same sign to yield an overflow. Its sign is therefore that of one of the operands, for example the first. For infinite operands X + -INF is negative, not positive. */ || (code == PLUS_EXPR && (sgn1 >= 0 ? !is_negative_overflow_infinity (val2) : is_positive_overflow_infinity (val2))) /* For subtraction, non-infinite operands must be of different signs to yield an overflow. Its sign is therefore that of the first operand or the opposite of that of the second operand. A first operand of 0 counts as positive here, for the corner case 0 - (-INF), which overflows, but must yield +INF. For infinite operands 0 - INF is negative, not positive. */ || (code == MINUS_EXPR && (sgn1 >= 0 ? !is_positive_overflow_infinity (val2) : is_negative_overflow_infinity (val2))) /* We only get in here with positive shift count, so the overflow direction is the same as the sign of val1. Actually rshift does not overflow at all, but we only handle the case of shifting overflowed -INF and +INF. */ || (code == RSHIFT_EXPR && sgn1 >= 0) /* For division, the only case is -INF / -1 = +INF. */ || code == TRUNC_DIV_EXPR || code == FLOOR_DIV_EXPR || code == CEIL_DIV_EXPR || code == EXACT_DIV_EXPR || code == ROUND_DIV_EXPR) return (needs_overflow_infinity (TREE_TYPE (res)) ? positive_overflow_infinity (TREE_TYPE (res)) : TYPE_MAX_VALUE (TREE_TYPE (res))); else return (needs_overflow_infinity (TREE_TYPE (res)) ? negative_overflow_infinity (TREE_TYPE (res)) : TYPE_MIN_VALUE (TREE_TYPE (res))); } return res; } /* For range VR compute two wide_int bitmasks. In *MAY_BE_NONZERO bitmask if some bit is unset, it means for all numbers in the range the bit is 0, otherwise it might be 0 or 1. In *MUST_BE_NONZERO bitmask if some bit is set, it means for all numbers in the range the bit is 1, otherwise it might be 0 or 1. */ static bool zero_nonzero_bits_from_vr (const tree expr_type, value_range *vr, wide_int *may_be_nonzero, wide_int *must_be_nonzero) { *may_be_nonzero = wi::minus_one (TYPE_PRECISION (expr_type)); *must_be_nonzero = wi::zero (TYPE_PRECISION (expr_type)); if (!range_int_cst_p (vr) || is_overflow_infinity (vr->min) || is_overflow_infinity (vr->max)) return false; if (range_int_cst_singleton_p (vr)) { *may_be_nonzero = vr->min; *must_be_nonzero = *may_be_nonzero; } else if (tree_int_cst_sgn (vr->min) >= 0 || tree_int_cst_sgn (vr->max) < 0) { wide_int xor_mask = wi::bit_xor (vr->min, vr->max); *may_be_nonzero = wi::bit_or (vr->min, vr->max); *must_be_nonzero = wi::bit_and (vr->min, vr->max); if (xor_mask != 0) { wide_int mask = wi::mask (wi::floor_log2 (xor_mask), false, may_be_nonzero->get_precision ()); *may_be_nonzero = *may_be_nonzero | mask; *must_be_nonzero = must_be_nonzero->and_not (mask); } } return true; } /* Create two value-ranges in *VR0 and *VR1 from the anti-range *AR so that *VR0 U *VR1 == *AR. Returns true if that is possible, false otherwise. If *AR can be represented with a single range *VR1 will be VR_UNDEFINED. */ static bool ranges_from_anti_range (value_range *ar, value_range *vr0, value_range *vr1) { tree type = TREE_TYPE (ar->min); vr0->type = VR_UNDEFINED; vr1->type = VR_UNDEFINED; if (ar->type != VR_ANTI_RANGE || TREE_CODE (ar->min) != INTEGER_CST || TREE_CODE (ar->max) != INTEGER_CST || !vrp_val_min (type) || !vrp_val_max (type)) return false; if (!vrp_val_is_min (ar->min)) { vr0->type = VR_RANGE; vr0->min = vrp_val_min (type); vr0->max = wide_int_to_tree (type, wi::sub (ar->min, 1)); } if (!vrp_val_is_max (ar->max)) { vr1->type = VR_RANGE; vr1->min = wide_int_to_tree (type, wi::add (ar->max, 1)); vr1->max = vrp_val_max (type); } if (vr0->type == VR_UNDEFINED) { *vr0 = *vr1; vr1->type = VR_UNDEFINED; } return vr0->type != VR_UNDEFINED; } /* Helper to extract a value-range *VR for a multiplicative operation *VR0 CODE *VR1. */ static void extract_range_from_multiplicative_op_1 (value_range *vr, enum tree_code code, value_range *vr0, value_range *vr1) { enum value_range_type type; tree val[4]; size_t i; tree min, max; bool sop; int cmp; /* Multiplications, divisions and shifts are a bit tricky to handle, depending on the mix of signs we have in the two ranges, we need to operate on different values to get the minimum and maximum values for the new range. One approach is to figure out all the variations of range combinations and do the operations. However, this involves several calls to compare_values and it is pretty convoluted. It's simpler to do the 4 operations (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP MAX1) and then figure the smallest and largest values to form the new range. */ gcc_assert (code == MULT_EXPR || code == TRUNC_DIV_EXPR || code == FLOOR_DIV_EXPR || code == CEIL_DIV_EXPR || code == EXACT_DIV_EXPR || code == ROUND_DIV_EXPR || code == RSHIFT_EXPR || code == LSHIFT_EXPR); gcc_assert ((vr0->type == VR_RANGE || (code == MULT_EXPR && vr0->type == VR_ANTI_RANGE)) && vr0->type == vr1->type); type = vr0->type; /* Compute the 4 cross operations. */ sop = false; val[0] = vrp_int_const_binop (code, vr0->min, vr1->min); if (val[0] == NULL_TREE) sop = true; if (vr1->max == vr1->min) val[1] = NULL_TREE; else { val[1] = vrp_int_const_binop (code, vr0->min, vr1->max); if (val[1] == NULL_TREE) sop = true; } if (vr0->max == vr0->min) val[2] = NULL_TREE; else { val[2] = vrp_int_const_binop (code, vr0->max, vr1->min); if (val[2] == NULL_TREE) sop = true; } if (vr0->min == vr0->max || vr1->min == vr1->max) val[3] = NULL_TREE; else { val[3] = vrp_int_const_binop (code, vr0->max, vr1->max); if (val[3] == NULL_TREE) sop = true; } if (sop) { set_value_range_to_varying (vr); return; } /* Set MIN to the minimum of VAL[i] and MAX to the maximum of VAL[i]. */ min = val[0]; max = val[0]; for (i = 1; i < 4; i++) { if (!is_gimple_min_invariant (min) || (TREE_OVERFLOW (min) && !is_overflow_infinity (min)) || !is_gimple_min_invariant (max) || (TREE_OVERFLOW (max) && !is_overflow_infinity (max))) break; if (val[i]) { if (!is_gimple_min_invariant (val[i]) || (TREE_OVERFLOW (val[i]) && !is_overflow_infinity (val[i]))) { /* If we found an overflowed value, set MIN and MAX to it so that we set the resulting range to VARYING. */ min = max = val[i]; break; } if (compare_values (val[i], min) == -1) min = val[i]; if (compare_values (val[i], max) == 1) max = val[i]; } } /* If either MIN or MAX overflowed, then set the resulting range to VARYING. But we do accept an overflow infinity representation. */ if (min == NULL_TREE || !is_gimple_min_invariant (min) || (TREE_OVERFLOW (min) && !is_overflow_infinity (min)) || max == NULL_TREE || !is_gimple_min_invariant (max) || (TREE_OVERFLOW (max) && !is_overflow_infinity (max))) { set_value_range_to_varying (vr); return; } /* We punt if: 1) [-INF, +INF] 2) [-INF, +-INF(OVF)] 3) [+-INF(OVF), +INF] 4) [+-INF(OVF), +-INF(OVF)] We learn nothing when we have INF and INF(OVF) on both sides. Note that we do accept [-INF, -INF] and [+INF, +INF] without overflow. */ if ((vrp_val_is_min (min) || is_overflow_infinity (min)) && (vrp_val_is_max (max) || is_overflow_infinity (max))) { set_value_range_to_varying (vr); return; } cmp = compare_values (min, max); if (cmp == -2 || cmp == 1) { /* If the new range has its limits swapped around (MIN > MAX), then the operation caused one of them to wrap around, mark the new range VARYING. */ set_value_range_to_varying (vr); } else set_value_range (vr, type, min, max, NULL); } /* Extract range information from a binary operation CODE based on the ranges of each of its operands *VR0 and *VR1 with resulting type EXPR_TYPE. The resulting range is stored in *VR. */ static void extract_range_from_binary_expr_1 (value_range *vr, enum tree_code code, tree expr_type, value_range *vr0_, value_range *vr1_) { value_range vr0 = *vr0_, vr1 = *vr1_; value_range vrtem0 = VR_INITIALIZER, vrtem1 = VR_INITIALIZER; enum value_range_type type; tree min = NULL_TREE, max = NULL_TREE; int cmp; if (!INTEGRAL_TYPE_P (expr_type) && !POINTER_TYPE_P (expr_type)) { set_value_range_to_varying (vr); return; } /* Not all binary expressions can be applied to ranges in a meaningful way. Handle only arithmetic operations. */ if (code != PLUS_EXPR && code != MINUS_EXPR && code != POINTER_PLUS_EXPR && code != MULT_EXPR && code != TRUNC_DIV_EXPR && code != FLOOR_DIV_EXPR && code != CEIL_DIV_EXPR && code != EXACT_DIV_EXPR && code != ROUND_DIV_EXPR && code != TRUNC_MOD_EXPR && code != RSHIFT_EXPR && code != LSHIFT_EXPR && code != MIN_EXPR && code != MAX_EXPR && code != BIT_AND_EXPR && code != BIT_IOR_EXPR && code != BIT_XOR_EXPR) { set_value_range_to_varying (vr); return; } /* If both ranges are UNDEFINED, so is the result. */ if (vr0.type == VR_UNDEFINED && vr1.type == VR_UNDEFINED) { set_value_range_to_undefined (vr); return; } /* If one of the ranges is UNDEFINED drop it to VARYING for the following code. At some point we may want to special-case operations that have UNDEFINED result for all or some value-ranges of the not UNDEFINED operand. */ else if (vr0.type == VR_UNDEFINED) set_value_range_to_varying (&vr0); else if (vr1.type == VR_UNDEFINED) set_value_range_to_varying (&vr1); /* Now canonicalize anti-ranges to ranges when they are not symbolic and express ~[] op X as ([]' op X) U ([]'' op X). */ if (vr0.type == VR_ANTI_RANGE && ranges_from_anti_range (&vr0, &vrtem0, &vrtem1)) { extract_range_from_binary_expr_1 (vr, code, expr_type, &vrtem0, vr1_); if (vrtem1.type != VR_UNDEFINED) { value_range vrres = VR_INITIALIZER; extract_range_from_binary_expr_1 (&vrres, code, expr_type, &vrtem1, vr1_); vrp_meet (vr, &vrres); } return; } /* Likewise for X op ~[]. */ if (vr1.type == VR_ANTI_RANGE && ranges_from_anti_range (&vr1, &vrtem0, &vrtem1)) { extract_range_from_binary_expr_1 (vr, code, expr_type, vr0_, &vrtem0); if (vrtem1.type != VR_UNDEFINED) { value_range vrres = VR_INITIALIZER; extract_range_from_binary_expr_1 (&vrres, code, expr_type, vr0_, &vrtem1); vrp_meet (vr, &vrres); } return; } /* The type of the resulting value range defaults to VR0.TYPE. */ type = vr0.type; /* Refuse to operate on VARYING ranges, ranges of different kinds and symbolic ranges. As an exception, we allow BIT_{AND,IOR} because we may be able to derive a useful range even if one of the operands is VR_VARYING or symbolic range. Similarly for divisions, MIN/MAX and PLUS/MINUS. TODO, we may be able to derive anti-ranges in some cases. */ if (code != BIT_AND_EXPR && code != BIT_IOR_EXPR && code != TRUNC_DIV_EXPR && code != FLOOR_DIV_EXPR && code != CEIL_DIV_EXPR && code != EXACT_DIV_EXPR && code != ROUND_DIV_EXPR && code != TRUNC_MOD_EXPR && code != MIN_EXPR && code != MAX_EXPR && code != PLUS_EXPR && code != MINUS_EXPR && code != RSHIFT_EXPR && (vr0.type == VR_VARYING || vr1.type == VR_VARYING || vr0.type != vr1.type || symbolic_range_p (&vr0) || symbolic_range_p (&vr1))) { set_value_range_to_varying (vr); return; } /* Now evaluate the expression to determine the new range. */ if (POINTER_TYPE_P (expr_type)) { if (code == MIN_EXPR || code == MAX_EXPR) { /* For MIN/MAX expressions with pointers, we only care about nullness, if both are non null, then the result is nonnull. If both are null, then the result is null. Otherwise they are varying. */ if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1)) set_value_range_to_nonnull (vr, expr_type); else if (range_is_null (&vr0) && range_is_null (&vr1)) set_value_range_to_null (vr, expr_type); else set_value_range_to_varying (vr); } else if (code == POINTER_PLUS_EXPR) { /* For pointer types, we are really only interested in asserting whether the expression evaluates to non-NULL. */ if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1)) set_value_range_to_nonnull (vr, expr_type); else if (range_is_null (&vr0) && range_is_null (&vr1)) set_value_range_to_null (vr, expr_type); else set_value_range_to_varying (vr); } else if (code == BIT_AND_EXPR) { /* For pointer types, we are really only interested in asserting whether the expression evaluates to non-NULL. */ if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1)) set_value_range_to_nonnull (vr, expr_type); else if (range_is_null (&vr0) || range_is_null (&vr1)) set_value_range_to_null (vr, expr_type); else set_value_range_to_varying (vr); } else set_value_range_to_varying (vr); return; } /* For integer ranges, apply the operation to each end of the range and see what we end up with. */ if (code == PLUS_EXPR || code == MINUS_EXPR) { const bool minus_p = (code == MINUS_EXPR); tree min_op0 = vr0.min; tree min_op1 = minus_p ? vr1.max : vr1.min; tree max_op0 = vr0.max; tree max_op1 = minus_p ? vr1.min : vr1.max; tree sym_min_op0 = NULL_TREE; tree sym_min_op1 = NULL_TREE; tree sym_max_op0 = NULL_TREE; tree sym_max_op1 = NULL_TREE; bool neg_min_op0, neg_min_op1, neg_max_op0, neg_max_op1; /* If we have a PLUS or MINUS with two VR_RANGEs, either constant or single-symbolic ranges, try to compute the precise resulting range, but only if we know that this resulting range will also be constant or single-symbolic. */ if (vr0.type == VR_RANGE && vr1.type == VR_RANGE && (TREE_CODE (min_op0) == INTEGER_CST || (sym_min_op0 = get_single_symbol (min_op0, &neg_min_op0, &min_op0))) && (TREE_CODE (min_op1) == INTEGER_CST || (sym_min_op1 = get_single_symbol (min_op1, &neg_min_op1, &min_op1))) && (!(sym_min_op0 && sym_min_op1) || (sym_min_op0 == sym_min_op1 && neg_min_op0 == (minus_p ? neg_min_op1 : !neg_min_op1))) && (TREE_CODE (max_op0) == INTEGER_CST || (sym_max_op0 = get_single_symbol (max_op0, &neg_max_op0, &max_op0))) && (TREE_CODE (max_op1) == INTEGER_CST || (sym_max_op1 = get_single_symbol (max_op1, &neg_max_op1, &max_op1))) && (!(sym_max_op0 && sym_max_op1) || (sym_max_op0 == sym_max_op1 && neg_max_op0 == (minus_p ? neg_max_op1 : !neg_max_op1)))) { const signop sgn = TYPE_SIGN (expr_type); const unsigned int prec = TYPE_PRECISION (expr_type); wide_int type_min, type_max, wmin, wmax; int min_ovf = 0; int max_ovf = 0; /* Get the lower and upper bounds of the type. */ if (TYPE_OVERFLOW_WRAPS (expr_type)) { type_min = wi::min_value (prec, sgn); type_max = wi::max_value (prec, sgn); } else { type_min = vrp_val_min (expr_type); type_max = vrp_val_max (expr_type); } /* Combine the lower bounds, if any. */ if (min_op0 && min_op1) { if (minus_p) { wmin = wi::sub (min_op0, min_op1); /* Check for overflow. */ if (wi::cmp (0, min_op1, sgn) != wi::cmp (wmin, min_op0, sgn)) min_ovf = wi::cmp (min_op0, min_op1, sgn); } else { wmin = wi::add (min_op0, min_op1); /* Check for overflow. */ if (wi::cmp (min_op1, 0, sgn) != wi::cmp (wmin, min_op0, sgn)) min_ovf = wi::cmp (min_op0, wmin, sgn); } } else if (min_op0) wmin = min_op0; else if (min_op1) wmin = minus_p ? wi::neg (min_op1) : min_op1; else wmin = wi::shwi (0, prec); /* Combine the upper bounds, if any. */ if (max_op0 && max_op1) { if (minus_p) { wmax = wi::sub (max_op0, max_op1); /* Check for overflow. */ if (wi::cmp (0, max_op1, sgn) != wi::cmp (wmax, max_op0, sgn)) max_ovf = wi::cmp (max_op0, max_op1, sgn); } else { wmax = wi::add (max_op0, max_op1); if (wi::cmp (max_op1, 0, sgn) != wi::cmp (wmax, max_op0, sgn)) max_ovf = wi::cmp (max_op0, wmax, sgn); } } else if (max_op0) wmax = max_op0; else if (max_op1) wmax = minus_p ? wi::neg (max_op1) : max_op1; else wmax = wi::shwi (0, prec); /* Check for type overflow. */ if (min_ovf == 0) { if (wi::cmp (wmin, type_min, sgn) == -1) min_ovf = -1; else if (wi::cmp (wmin, type_max, sgn) == 1) min_ovf = 1; } if (max_ovf == 0) { if (wi::cmp (wmax, type_min, sgn) == -1) max_ovf = -1; else if (wi::cmp (wmax, type_max, sgn) == 1) max_ovf = 1; } /* If we have overflow for the constant part and the resulting range will be symbolic, drop to VR_VARYING. */ if ((min_ovf && sym_min_op0 != sym_min_op1) || (max_ovf && sym_max_op0 != sym_max_op1)) { set_value_range_to_varying (vr); return; } if (TYPE_OVERFLOW_WRAPS (expr_type)) { /* If overflow wraps, truncate the values and adjust the range kind and bounds appropriately. */ wide_int tmin = wide_int::from (wmin, prec, sgn); wide_int tmax = wide_int::from (wmax, prec, sgn); if (min_ovf == max_ovf) { /* No overflow or both overflow or underflow. The range kind stays VR_RANGE. */ min = wide_int_to_tree (expr_type, tmin); max = wide_int_to_tree (expr_type, tmax); } else if ((min_ovf == -1 && max_ovf == 0) || (max_ovf == 1 && min_ovf == 0)) { /* Min underflow or max overflow. The range kind changes to VR_ANTI_RANGE. */ bool covers = false; wide_int tem = tmin; type = VR_ANTI_RANGE; tmin = tmax + 1; if (wi::cmp (tmin, tmax, sgn) < 0) covers = true; tmax = tem - 1; if (wi::cmp (tmax, tem, sgn) > 0) covers = true; /* If the anti-range would cover nothing, drop to varying. Likewise if the anti-range bounds are outside of the types values. */ if (covers || wi::cmp (tmin, tmax, sgn) > 0) { set_value_range_to_varying (vr); return; } min = wide_int_to_tree (expr_type, tmin); max = wide_int_to_tree (expr_type, tmax); } else { /* Other underflow and/or overflow, drop to VR_VARYING. */ set_value_range_to_varying (vr); return; } } else { /* If overflow does not wrap, saturate to the types min/max value. */ if (min_ovf == -1) { if (needs_overflow_infinity (expr_type) && supports_overflow_infinity (expr_type)) min = negative_overflow_infinity (expr_type); else min = wide_int_to_tree (expr_type, type_min); } else if (min_ovf == 1) { if (needs_overflow_infinity (expr_type) && supports_overflow_infinity (expr_type)) min = positive_overflow_infinity (expr_type); else min = wide_int_to_tree (expr_type, type_max); } else min = wide_int_to_tree (expr_type, wmin); if (max_ovf == -1) { if (needs_overflow_infinity (expr_type) && supports_overflow_infinity (expr_type)) max = negative_overflow_infinity (expr_type); else max = wide_int_to_tree (expr_type, type_min); } else if (max_ovf == 1) { if (needs_overflow_infinity (expr_type) && supports_overflow_infinity (expr_type)) max = positive_overflow_infinity (expr_type); else max = wide_int_to_tree (expr_type, type_max); } else max = wide_int_to_tree (expr_type, wmax); } if (needs_overflow_infinity (expr_type) && supports_overflow_infinity (expr_type)) { if ((min_op0 && is_negative_overflow_infinity (min_op0)) || (min_op1 && (minus_p ? is_positive_overflow_infinity (min_op1) : is_negative_overflow_infinity (min_op1)))) min = negative_overflow_infinity (expr_type); if ((max_op0 && is_positive_overflow_infinity (max_op0)) || (max_op1 && (minus_p ? is_negative_overflow_infinity (max_op1) : is_positive_overflow_infinity (max_op1)))) max = positive_overflow_infinity (expr_type); } /* If the result lower bound is constant, we're done; otherwise, build the symbolic lower bound. */ if (sym_min_op0 == sym_min_op1) ; else if (sym_min_op0) min = build_symbolic_expr (expr_type, sym_min_op0, neg_min_op0, min); else if (sym_min_op1) min = build_symbolic_expr (expr_type, sym_min_op1, neg_min_op1 ^ minus_p, min); /* Likewise for the upper bound. */ if (sym_max_op0 == sym_max_op1) ; else if (sym_max_op0) max = build_symbolic_expr (expr_type, sym_max_op0, neg_max_op0, max); else if (sym_max_op1) max = build_symbolic_expr (expr_type, sym_max_op1, neg_max_op1 ^ minus_p, max); } else { /* For other cases, for example if we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to VR_VARYING. It would take more effort to compute a precise range for such a case. ??? General even mixed range kind operations can be expressed by for example transforming ~[3, 5] + [1, 2] to range-only operations and a union primitive: [-INF, 2] + [1, 2] U [5, +INF] + [1, 2] [-INF+1, 4] U [6, +INF(OVF)] though usually the union is not exactly representable with a single range or anti-range as the above is [-INF+1, +INF(OVF)] intersected with ~[5, 5] but one could use a scheme similar to equivalences for this. */ set_value_range_to_varying (vr); return; } } else if (code == MIN_EXPR || code == MAX_EXPR) { if (vr0.type == VR_RANGE && !symbolic_range_p (&vr0)) { type = VR_RANGE; if (vr1.type == VR_RANGE && !symbolic_range_p (&vr1)) { /* For operations that make the resulting range directly proportional to the original ranges, apply the operation to the same end of each range. */ min = vrp_int_const_binop (code, vr0.min, vr1.min); max = vrp_int_const_binop (code, vr0.max, vr1.max); } else if (code == MIN_EXPR) { min = vrp_val_min (expr_type); max = vr0.max; } else if (code == MAX_EXPR) { min = vr0.min; max = vrp_val_max (expr_type); } } else if (vr1.type == VR_RANGE && !symbolic_range_p (&vr1)) { type = VR_RANGE; if (code == MIN_EXPR) { min = vrp_val_min (expr_type); max = vr1.max; } else if (code == MAX_EXPR) { min = vr1.min; max = vrp_val_max (expr_type); } } else { set_value_range_to_varying (vr); return; } } else if (code == MULT_EXPR) { /* Fancy code so that with unsigned, [-3,-1]*[-3,-1] does not drop to varying. This test requires 2*prec bits if both operands are signed and 2*prec + 2 bits if either is not. */ signop sign = TYPE_SIGN (expr_type); unsigned int prec = TYPE_PRECISION (expr_type); if (range_int_cst_p (&vr0) && range_int_cst_p (&vr1) && TYPE_OVERFLOW_WRAPS (expr_type)) { typedef FIXED_WIDE_INT (WIDE_INT_MAX_PRECISION * 2) vrp_int; typedef generic_wide_int <wi::extended_tree <WIDE_INT_MAX_PRECISION * 2> > vrp_int_cst; vrp_int sizem1 = wi::mask <vrp_int> (prec, false); vrp_int size = sizem1 + 1; /* Extend the values using the sign of the result to PREC2. From here on out, everthing is just signed math no matter what the input types were. */ vrp_int min0 = vrp_int_cst (vr0.min); vrp_int max0 = vrp_int_cst (vr0.max); vrp_int min1 = vrp_int_cst (vr1.min); vrp_int max1 = vrp_int_cst (vr1.max); /* Canonicalize the intervals. */ if (sign == UNSIGNED) { if (wi::ltu_p (size, min0 + max0)) { min0 -= size; max0 -= size; } if (wi::ltu_p (size, min1 + max1)) { min1 -= size; max1 -= size; } } vrp_int prod0 = min0 * min1; vrp_int prod1 = min0 * max1; vrp_int prod2 = max0 * min1; vrp_int prod3 = max0 * max1; /* Sort the 4 products so that min is in prod0 and max is in prod3. */ /* min0min1 > max0max1 */ if (prod0 > prod3) std::swap (prod0, prod3); /* min0max1 > max0min1 */ if (prod1 > prod2) std::swap (prod1, prod2); if (prod0 > prod1) std::swap (prod0, prod1); if (prod2 > prod3) std::swap (prod2, prod3); /* diff = max - min. */ prod2 = prod3 - prod0; if (wi::geu_p (prod2, sizem1)) { /* the range covers all values. */ set_value_range_to_varying (vr); return; } /* The following should handle the wrapping and selecting VR_ANTI_RANGE for us. */ min = wide_int_to_tree (expr_type, prod0); max = wide_int_to_tree (expr_type, prod3); set_and_canonicalize_value_range (vr, VR_RANGE, min, max, NULL); return; } /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs, drop to VR_VARYING. It would take more effort to compute a precise range for such a case. For example, if we have op0 == 65536 and op1 == 65536 with their ranges both being ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so we cannot claim that the product is in ~[0,0]. Note that we are guaranteed to have vr0.type == vr1.type at this point. */ if (vr0.type == VR_ANTI_RANGE && !TYPE_OVERFLOW_UNDEFINED (expr_type)) { set_value_range_to_varying (vr); return; } extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1); return; } else if (code == RSHIFT_EXPR || code == LSHIFT_EXPR) { /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1], then drop to VR_VARYING. Outside of this range we get undefined behavior from the shift operation. We cannot even trust SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl shifts, and the operation at the tree level may be widened. */ if (range_int_cst_p (&vr1) && compare_tree_int (vr1.min, 0) >= 0 && compare_tree_int (vr1.max, TYPE_PRECISION (expr_type)) == -1) { if (code == RSHIFT_EXPR) { /* Even if vr0 is VARYING or otherwise not usable, we can derive useful ranges just from the shift count. E.g. x >> 63 for signed 64-bit x is always [-1, 0]. */ if (vr0.type != VR_RANGE || symbolic_range_p (&vr0)) { vr0.type = type = VR_RANGE; vr0.min = vrp_val_min (expr_type); vr0.max = vrp_val_max (expr_type); } extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1); return; } /* We can map lshifts by constants to MULT_EXPR handling. */ else if (code == LSHIFT_EXPR && range_int_cst_singleton_p (&vr1)) { bool saved_flag_wrapv; value_range vr1p = VR_INITIALIZER; vr1p.type = VR_RANGE; vr1p.min = (wide_int_to_tree (expr_type, wi::set_bit_in_zero (tree_to_shwi (vr1.min), TYPE_PRECISION (expr_type)))); vr1p.max = vr1p.min; /* We have to use a wrapping multiply though as signed overflow on lshifts is implementation defined in C89. */ saved_flag_wrapv = flag_wrapv; flag_wrapv = 1; extract_range_from_binary_expr_1 (vr, MULT_EXPR, expr_type, &vr0, &vr1p); flag_wrapv = saved_flag_wrapv; return; } else if (code == LSHIFT_EXPR && range_int_cst_p (&vr0)) { int prec = TYPE_PRECISION (expr_type); int overflow_pos = prec; int bound_shift; wide_int low_bound, high_bound; bool uns = TYPE_UNSIGNED (expr_type); bool in_bounds = false; if (!uns) overflow_pos -= 1; bound_shift = overflow_pos - tree_to_shwi (vr1.max); /* If bound_shift == HOST_BITS_PER_WIDE_INT, the llshift can overflow. However, for that to happen, vr1.max needs to be zero, which means vr1 is a singleton range of zero, which means it should be handled by the previous LSHIFT_EXPR if-clause. */ wide_int bound = wi::set_bit_in_zero (bound_shift, prec); wide_int complement = ~(bound - 1); if (uns) { low_bound = bound; high_bound = complement; if (wi::ltu_p (vr0.max, low_bound)) { /* [5, 6] << [1, 2] == [10, 24]. */ /* We're shifting out only zeroes, the value increases monotonically. */ in_bounds = true; } else if (wi::ltu_p (high_bound, vr0.min)) { /* [0xffffff00, 0xffffffff] << [1, 2] == [0xfffffc00, 0xfffffffe]. */ /* We're shifting out only ones, the value decreases monotonically. */ in_bounds = true; } } else { /* [-1, 1] << [1, 2] == [-4, 4]. */ low_bound = complement; high_bound = bound; if (wi::lts_p (vr0.max, high_bound) && wi::lts_p (low_bound, vr0.min)) { /* For non-negative numbers, we're shifting out only zeroes, the value increases monotonically. For negative numbers, we're shifting out only ones, the value decreases monotomically. */ in_bounds = true; } } if (in_bounds) { extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1); return; } } } set_value_range_to_varying (vr); return; } else if (code == TRUNC_DIV_EXPR || code == FLOOR_DIV_EXPR || code == CEIL_DIV_EXPR || code == EXACT_DIV_EXPR || code == ROUND_DIV_EXPR) { if (vr0.type != VR_RANGE || symbolic_range_p (&vr0)) { /* For division, if op1 has VR_RANGE but op0 does not, something can be deduced just from that range. Say [min, max] / [4, max] gives [min / 4, max / 4] range. */ if (vr1.type == VR_RANGE && !symbolic_range_p (&vr1) && range_includes_zero_p (vr1.min, vr1.max) == 0) { vr0.type = type = VR_RANGE; vr0.min = vrp_val_min (expr_type); vr0.max = vrp_val_max (expr_type); } else { set_value_range_to_varying (vr); return; } } /* For divisions, if flag_non_call_exceptions is true, we must not eliminate a division by zero. */ if (cfun->can_throw_non_call_exceptions && (vr1.type != VR_RANGE || range_includes_zero_p (vr1.min, vr1.max) != 0)) { set_value_range_to_varying (vr); return; } /* For divisions, if op0 is VR_RANGE, we can deduce a range even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can include 0. */ if (vr0.type == VR_RANGE && (vr1.type != VR_RANGE || range_includes_zero_p (vr1.min, vr1.max) != 0)) { tree zero = build_int_cst (TREE_TYPE (vr0.min), 0); int cmp; min = NULL_TREE; max = NULL_TREE; if (TYPE_UNSIGNED (expr_type) || value_range_nonnegative_p (&vr1)) { /* For unsigned division or when divisor is known to be non-negative, the range has to cover all numbers from 0 to max for positive max and all numbers from min to 0 for negative min. */ cmp = compare_values (vr0.max, zero); if (cmp == -1) { /* When vr0.max < 0, vr1.min != 0 and value ranges for dividend and divisor are available. */ if (vr1.type == VR_RANGE && !symbolic_range_p (&vr0) && !symbolic_range_p (&vr1) && compare_values (vr1.min, zero) != 0) max = int_const_binop (code, vr0.max, vr1.min); else max = zero; } else if (cmp == 0 || cmp == 1) max = vr0.max; else type = VR_VARYING; cmp = compare_values (vr0.min, zero); if (cmp == 1) { /* For unsigned division when value ranges for dividend and divisor are available. */ if (vr1.type == VR_RANGE && !symbolic_range_p (&vr0) && !symbolic_range_p (&vr1) && compare_values (vr1.max, zero) != 0) min = int_const_binop (code, vr0.min, vr1.max); else min = zero; } else if (cmp == 0 || cmp == -1) min = vr0.min; else type = VR_VARYING; } else { /* Otherwise the range is -max .. max or min .. -min depending on which bound is bigger in absolute value, as the division can change the sign. */ abs_extent_range (vr, vr0.min, vr0.max); return; } if (type == VR_VARYING) { set_value_range_to_varying (vr); return; } } else if (!symbolic_range_p (&vr0) && !symbolic_range_p (&vr1)) { extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1); return; } } else if (code == TRUNC_MOD_EXPR) { if (range_is_null (&vr1)) { set_value_range_to_undefined (vr); return; } /* ABS (A % B) < ABS (B) and either 0 <= A % B <= A or A <= A % B <= 0. */ type = VR_RANGE; signop sgn = TYPE_SIGN (expr_type); unsigned int prec = TYPE_PRECISION (expr_type); wide_int wmin, wmax, tmp; wide_int zero = wi::zero (prec); wide_int one = wi::one (prec); if (vr1.type == VR_RANGE && !symbolic_range_p (&vr1)) { wmax = wi::sub (vr1.max, one); if (sgn == SIGNED) { tmp = wi::sub (wi::minus_one (prec), vr1.min); wmax = wi::smax (wmax, tmp); } } else { wmax = wi::max_value (prec, sgn); /* X % INT_MIN may be INT_MAX. */ if (sgn == UNSIGNED) wmax = wmax - one; } if (sgn == UNSIGNED) wmin = zero; else { wmin = -wmax; if (vr0.type == VR_RANGE && TREE_CODE (vr0.min) == INTEGER_CST) { tmp = vr0.min; if (wi::gts_p (tmp, zero)) tmp = zero; wmin = wi::smax (wmin, tmp); } } if (vr0.type == VR_RANGE && TREE_CODE (vr0.max) == INTEGER_CST) { tmp = vr0.max; if (sgn == SIGNED && wi::neg_p (tmp)) tmp = zero; wmax = wi::min (wmax, tmp, sgn); } min = wide_int_to_tree (expr_type, wmin); max = wide_int_to_tree (expr_type, wmax); } else if (code == BIT_AND_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR) { bool int_cst_range0, int_cst_range1; wide_int may_be_nonzero0, may_be_nonzero1; wide_int must_be_nonzero0, must_be_nonzero1; int_cst_range0 = zero_nonzero_bits_from_vr (expr_type, &vr0, &may_be_nonzero0, &must_be_nonzero0); int_cst_range1 = zero_nonzero_bits_from_vr (expr_type, &vr1, &may_be_nonzero1, &must_be_nonzero1); type = VR_RANGE; if (code == BIT_AND_EXPR) { min = wide_int_to_tree (expr_type, must_be_nonzero0 & must_be_nonzero1); wide_int wmax = may_be_nonzero0 & may_be_nonzero1; /* If both input ranges contain only negative values we can truncate the result range maximum to the minimum of the input range maxima. */ if (int_cst_range0 && int_cst_range1 && tree_int_cst_sgn (vr0.max) < 0 && tree_int_cst_sgn (vr1.max) < 0) { wmax = wi::min (wmax, vr0.max, TYPE_SIGN (expr_type)); wmax = wi::min (wmax, vr1.max, TYPE_SIGN (expr_type)); } /* If either input range contains only non-negative values we can truncate the result range maximum to the respective maximum of the input range. */ if (int_cst_range0 && tree_int_cst_sgn (vr0.min) >= 0) wmax = wi::min (wmax, vr0.max, TYPE_SIGN (expr_type)); if (int_cst_range1 && tree_int_cst_sgn (vr1.min) >= 0) wmax = wi::min (wmax, vr1.max, TYPE_SIGN (expr_type)); max = wide_int_to_tree (expr_type, wmax); cmp = compare_values (min, max); /* PR68217: In case of signed & sign-bit-CST should result in [-INF, 0] instead of [-INF, INF]. */ if (cmp == -2 || cmp == 1) { wide_int sign_bit = wi::set_bit_in_zero (TYPE_PRECISION (expr_type) - 1, TYPE_PRECISION (expr_type)); if (!TYPE_UNSIGNED (expr_type) && ((value_range_constant_singleton (&vr0) && !wi::cmps (vr0.min, sign_bit)) || (value_range_constant_singleton (&vr1) && !wi::cmps (vr1.min, sign_bit)))) { min = TYPE_MIN_VALUE (expr_type); max = build_int_cst (expr_type, 0); } } } else if (code == BIT_IOR_EXPR) { max = wide_int_to_tree (expr_type, may_be_nonzero0 | may_be_nonzero1); wide_int wmin = must_be_nonzero0 | must_be_nonzero1; /* If the input ranges contain only positive values we can truncate the minimum of the result range to the maximum of the input range minima. */ if (int_cst_range0 && int_cst_range1 && tree_int_cst_sgn (vr0.min) >= 0 && tree_int_cst_sgn (vr1.min) >= 0) { wmin = wi::max (wmin, vr0.min, TYPE_SIGN (expr_type)); wmin = wi::max (wmin, vr1.min, TYPE_SIGN (expr_type)); } /* If either input range contains only negative values we can truncate the minimum of the result range to the respective minimum range. */ if (int_cst_range0 && tree_int_cst_sgn (vr0.max) < 0) wmin = wi::max (wmin, vr0.min, TYPE_SIGN (expr_type)); if (int_cst_range1 && tree_int_cst_sgn (vr1.max) < 0) wmin = wi::max (wmin, vr1.min, TYPE_SIGN (expr_type)); min = wide_int_to_tree (expr_type, wmin); } else if (code == BIT_XOR_EXPR) { wide_int result_zero_bits = ((must_be_nonzero0 & must_be_nonzero1) | ~(may_be_nonzero0 | may_be_nonzero1)); wide_int result_one_bits = (must_be_nonzero0.and_not (may_be_nonzero1) | must_be_nonzero1.and_not (may_be_nonzero0)); max = wide_int_to_tree (expr_type, ~result_zero_bits); min = wide_int_to_tree (expr_type, result_one_bits); /* If the range has all positive or all negative values the result is better than VARYING. */ if (tree_int_cst_sgn (min) < 0 || tree_int_cst_sgn (max) >= 0) ; else max = min = NULL_TREE; } } else gcc_unreachable (); /* If either MIN or MAX overflowed, then set the resulting range to VARYING. But we do accept an overflow infinity representation. */ if (min == NULL_TREE || (TREE_OVERFLOW_P (min) && !is_overflow_infinity (min)) || max == NULL_TREE || (TREE_OVERFLOW_P (max) && !is_overflow_infinity (max))) { set_value_range_to_varying (vr); return; } /* We punt if: 1) [-INF, +INF] 2) [-INF, +-INF(OVF)] 3) [+-INF(OVF), +INF] 4) [+-INF(OVF), +-INF(OVF)] We learn nothing when we have INF and INF(OVF) on both sides. Note that we do accept [-INF, -INF] and [+INF, +INF] without overflow. */ if ((vrp_val_is_min (min) || is_overflow_infinity (min)) && (vrp_val_is_max (max) || is_overflow_infinity (max))) { set_value_range_to_varying (vr); return; } cmp = compare_values (min, max); if (cmp == -2 || cmp == 1) { /* If the new range has its limits swapped around (MIN > MAX), then the operation caused one of them to wrap around, mark the new range VARYING. */ set_value_range_to_varying (vr); } else set_value_range (vr, type, min, max, NULL); } /* Extract range information from a binary expression OP0 CODE OP1 based on the ranges of each of its operands with resulting type EXPR_TYPE. The resulting range is stored in *VR. */ static void extract_range_from_binary_expr (value_range *vr, enum tree_code code, tree expr_type, tree op0, tree op1) { value_range vr0 = VR_INITIALIZER; value_range vr1 = VR_INITIALIZER; /* Get value ranges for each operand. For constant operands, create a new value range with the operand to simplify processing. */ if (TREE_CODE (op0) == SSA_NAME) vr0 = *(get_value_range (op0)); else if (is_gimple_min_invariant (op0)) set_value_range_to_value (&vr0, op0, NULL); else set_value_range_to_varying (&vr0); if (TREE_CODE (op1) == SSA_NAME) vr1 = *(get_value_range (op1)); else if (is_gimple_min_invariant (op1)) set_value_range_to_value (&vr1, op1, NULL); else set_value_range_to_varying (&vr1); extract_range_from_binary_expr_1 (vr, code, expr_type, &vr0, &vr1); /* Try harder for PLUS and MINUS if the range of one operand is symbolic and based on the other operand, for example if it was deduced from a symbolic comparison. When a bound of the range of the first operand is invariant, we set the corresponding bound of the new range to INF in order to avoid recursing on the range of the second operand. */ if (vr->type == VR_VARYING && (code == PLUS_EXPR || code == MINUS_EXPR) && TREE_CODE (op1) == SSA_NAME && vr0.type == VR_RANGE && symbolic_range_based_on_p (&vr0, op1)) { const bool minus_p = (code == MINUS_EXPR); value_range n_vr1 = VR_INITIALIZER; /* Try with VR0 and [-INF, OP1]. */ if (is_gimple_min_invariant (minus_p ? vr0.max : vr0.min)) set_value_range (&n_vr1, VR_RANGE, vrp_val_min (expr_type), op1, NULL); /* Try with VR0 and [OP1, +INF]. */ else if (is_gimple_min_invariant (minus_p ? vr0.min : vr0.max)) set_value_range (&n_vr1, VR_RANGE, op1, vrp_val_max (expr_type), NULL); /* Try with VR0 and [OP1, OP1]. */ else set_value_range (&n_vr1, VR_RANGE, op1, op1, NULL); extract_range_from_binary_expr_1 (vr, code, expr_type, &vr0, &n_vr1); } if (vr->type == VR_VARYING && (code == PLUS_EXPR || code == MINUS_EXPR) && TREE_CODE (op0) == SSA_NAME && vr1.type == VR_RANGE && symbolic_range_based_on_p (&vr1, op0)) { const bool minus_p = (code == MINUS_EXPR); value_range n_vr0 = VR_INITIALIZER; /* Try with [-INF, OP0] and VR1. */ if (is_gimple_min_invariant (minus_p ? vr1.max : vr1.min)) set_value_range (&n_vr0, VR_RANGE, vrp_val_min (expr_type), op0, NULL); /* Try with [OP0, +INF] and VR1. */ else if (is_gimple_min_invariant (minus_p ? vr1.min : vr1.max)) set_value_range (&n_vr0, VR_RANGE, op0, vrp_val_max (expr_type), NULL); /* Try with [OP0, OP0] and VR1. */ else set_value_range (&n_vr0, VR_RANGE, op0, op0, NULL); extract_range_from_binary_expr_1 (vr, code, expr_type, &n_vr0, &vr1); } } /* Extract range information from a unary operation CODE based on the range of its operand *VR0 with type OP0_TYPE with resulting type TYPE. The resulting range is stored in *VR. */ void extract_range_from_unary_expr (value_range *vr, enum tree_code code, tree type, value_range *vr0_, tree op0_type) { value_range vr0 = *vr0_, vrtem0 = VR_INITIALIZER, vrtem1 = VR_INITIALIZER; /* VRP only operates on integral and pointer types. */ if (!(INTEGRAL_TYPE_P (op0_type) || POINTER_TYPE_P (op0_type)) || !(INTEGRAL_TYPE_P (type) || POINTER_TYPE_P (type))) { set_value_range_to_varying (vr); return; } /* If VR0 is UNDEFINED, so is the result. */ if (vr0.type == VR_UNDEFINED) { set_value_range_to_undefined (vr); return; } /* Handle operations that we express in terms of others. */ if (code == PAREN_EXPR || code == OBJ_TYPE_REF) { /* PAREN_EXPR and OBJ_TYPE_REF are simple copies. */ copy_value_range (vr, &vr0); return; } else if (code == NEGATE_EXPR) { /* -X is simply 0 - X, so re-use existing code that also handles anti-ranges fine. */ value_range zero = VR_INITIALIZER; set_value_range_to_value (&zero, build_int_cst (type, 0), NULL); extract_range_from_binary_expr_1 (vr, MINUS_EXPR, type, &zero, &vr0); return; } else if (code == BIT_NOT_EXPR) { /* ~X is simply -1 - X, so re-use existing code that also handles anti-ranges fine. */ value_range minusone = VR_INITIALIZER; set_value_range_to_value (&minusone, build_int_cst (type, -1), NULL); extract_range_from_binary_expr_1 (vr, MINUS_EXPR, type, &minusone, &vr0); return; } /* Now canonicalize anti-ranges to ranges when they are not symbolic and express op ~[] as (op []') U (op []''). */ if (vr0.type == VR_ANTI_RANGE && ranges_from_anti_range (&vr0, &vrtem0, &vrtem1)) { extract_range_from_unary_expr (vr, code, type, &vrtem0, op0_type); if (vrtem1.type != VR_UNDEFINED) { value_range vrres = VR_INITIALIZER; extract_range_from_unary_expr (&vrres, code, type, &vrtem1, op0_type); vrp_meet (vr, &vrres); } return; } if (CONVERT_EXPR_CODE_P (code)) { tree inner_type = op0_type; tree outer_type = type; /* If the expression evaluates to a pointer, we are only interested in determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */ if (POINTER_TYPE_P (type)) { if (range_is_nonnull (&vr0)) set_value_range_to_nonnull (vr, type); else if (range_is_null (&vr0)) set_value_range_to_null (vr, type); else set_value_range_to_varying (vr); return; } /* If VR0 is varying and we increase the type precision, assume a full range for the following transformation. */ if (vr0.type == VR_VARYING && INTEGRAL_TYPE_P (inner_type) && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type)) { vr0.type = VR_RANGE; vr0.min = TYPE_MIN_VALUE (inner_type); vr0.max = TYPE_MAX_VALUE (inner_type); } /* If VR0 is a constant range or anti-range and the conversion is not truncating we can convert the min and max values and canonicalize the resulting range. Otherwise we can do the conversion if the size of the range is less than what the precision of the target type can represent and the range is not an anti-range. */ if ((vr0.type == VR_RANGE || vr0.type == VR_ANTI_RANGE) && TREE_CODE (vr0.min) == INTEGER_CST && TREE_CODE (vr0.max) == INTEGER_CST && (!is_overflow_infinity (vr0.min) || (vr0.type == VR_RANGE && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type) && needs_overflow_infinity (outer_type) && supports_overflow_infinity (outer_type))) && (!is_overflow_infinity (vr0.max) || (vr0.type == VR_RANGE && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type) && needs_overflow_infinity (outer_type) && supports_overflow_infinity (outer_type))) && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type) || (vr0.type == VR_RANGE && integer_zerop (int_const_binop (RSHIFT_EXPR, int_const_binop (MINUS_EXPR, vr0.max, vr0.min), size_int (TYPE_PRECISION (outer_type))))))) { tree new_min, new_max; if (is_overflow_infinity (vr0.min)) new_min = negative_overflow_infinity (outer_type); else new_min = force_fit_type (outer_type, wi::to_widest (vr0.min), 0, false); if (is_overflow_infinity (vr0.max)) new_max = positive_overflow_infinity (outer_type); else new_max = force_fit_type (outer_type, wi::to_widest (vr0.max), 0, false); set_and_canonicalize_value_range (vr, vr0.type, new_min, new_max, NULL); return; } set_value_range_to_varying (vr); return; } else if (code == ABS_EXPR) { tree min, max; int cmp; /* Pass through vr0 in the easy cases. */ if (TYPE_UNSIGNED (type) || value_range_nonnegative_p (&vr0)) { copy_value_range (vr, &vr0); return; } /* For the remaining varying or symbolic ranges we can't do anything useful. */ if (vr0.type == VR_VARYING || symbolic_range_p (&vr0)) { set_value_range_to_varying (vr); return; } /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a useful range. */ if (!TYPE_OVERFLOW_UNDEFINED (type) && ((vr0.type == VR_RANGE && vrp_val_is_min (vr0.min)) || (vr0.type == VR_ANTI_RANGE && !vrp_val_is_min (vr0.min)))) { set_value_range_to_varying (vr); return; } /* ABS_EXPR may flip the range around, if the original range included negative values. */ if (is_overflow_infinity (vr0.min)) min = positive_overflow_infinity (type); else if (!vrp_val_is_min (vr0.min)) min = fold_unary_to_constant (code, type, vr0.min); else if (!needs_overflow_infinity (type)) min = TYPE_MAX_VALUE (type); else if (supports_overflow_infinity (type)) min = positive_overflow_infinity (type); else { set_value_range_to_varying (vr); return; } if (is_overflow_infinity (vr0.max)) max = positive_overflow_infinity (type); else if (!vrp_val_is_min (vr0.max)) max = fold_unary_to_constant (code, type, vr0.max); else if (!needs_overflow_infinity (type)) max = TYPE_MAX_VALUE (type); else if (supports_overflow_infinity (type) /* We shouldn't generate [+INF, +INF] as set_value_range doesn't like this and ICEs. */ && !is_positive_overflow_infinity (min)) max = positive_overflow_infinity (type); else { set_value_range_to_varying (vr); return; } cmp = compare_values (min, max); /* If a VR_ANTI_RANGEs contains zero, then we have ~[-INF, min(MIN, MAX)]. */ if (vr0.type == VR_ANTI_RANGE) { if (range_includes_zero_p (vr0.min, vr0.max) == 1) { /* Take the lower of the two values. */ if (cmp != 1) max = min; /* Create ~[-INF, min (abs(MIN), abs(MAX))] or ~[-INF + 1, min (abs(MIN), abs(MAX))] when flag_wrapv is set and the original anti-range doesn't include TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */ if (TYPE_OVERFLOW_WRAPS (type)) { tree type_min_value = TYPE_MIN_VALUE (type); min = (vr0.min != type_min_value ? int_const_binop (PLUS_EXPR, type_min_value, build_int_cst (TREE_TYPE (type_min_value), 1)) : type_min_value); } else { if (overflow_infinity_range_p (&vr0)) min = negative_overflow_infinity (type); else min = TYPE_MIN_VALUE (type); } } else { /* All else has failed, so create the range [0, INF], even for flag_wrapv since TYPE_MIN_VALUE is in the original anti-range. */ vr0.type = VR_RANGE; min = build_int_cst (type, 0); if (needs_overflow_infinity (type)) { if (supports_overflow_infinity (type)) max = positive_overflow_infinity (type); else { set_value_range_to_varying (vr); return; } } else max = TYPE_MAX_VALUE (type); } } /* If the range contains zero then we know that the minimum value in the range will be zero. */ else if (range_includes_zero_p (vr0.min, vr0.max) == 1) { if (cmp == 1) max = min; min = build_int_cst (type, 0); } else { /* If the range was reversed, swap MIN and MAX. */ if (cmp == 1) std::swap (min, max); } cmp = compare_values (min, max); if (cmp == -2 || cmp == 1) { /* If the new range has its limits swapped around (MIN > MAX), then the operation caused one of them to wrap around, mark the new range VARYING. */ set_value_range_to_varying (vr); } else set_value_range (vr, vr0.type, min, max, NULL); return; } /* For unhandled operations fall back to varying. */ set_value_range_to_varying (vr); return; } /* Extract range information from a unary expression CODE OP0 based on the range of its operand with resulting type TYPE. The resulting range is stored in *VR. */ static void extract_range_from_unary_expr (value_range *vr, enum tree_code code, tree type, tree op0) { value_range vr0 = VR_INITIALIZER; /* Get value ranges for the operand. For constant operands, create a new value range with the operand to simplify processing. */ if (TREE_CODE (op0) == SSA_NAME) vr0 = *(get_value_range (op0)); else if (is_gimple_min_invariant (op0)) set_value_range_to_value (&vr0, op0, NULL); else set_value_range_to_varying (&vr0); extract_range_from_unary_expr (vr, code, type, &vr0, TREE_TYPE (op0)); } /* Extract range information from a conditional expression STMT based on the ranges of each of its operands and the expression code. */ static void extract_range_from_cond_expr (value_range *vr, gassign *stmt) { tree op0, op1; value_range vr0 = VR_INITIALIZER; value_range vr1 = VR_INITIALIZER; /* Get value ranges for each operand. For constant operands, create a new value range with the operand to simplify processing. */ op0 = gimple_assign_rhs2 (stmt); if (TREE_CODE (op0) == SSA_NAME) vr0 = *(get_value_range (op0)); else if (is_gimple_min_invariant (op0)) set_value_range_to_value (&vr0, op0, NULL); else set_value_range_to_varying (&vr0); op1 = gimple_assign_rhs3 (stmt); if (TREE_CODE (op1) == SSA_NAME) vr1 = *(get_value_range (op1)); else if (is_gimple_min_invariant (op1)) set_value_range_to_value (&vr1, op1, NULL); else set_value_range_to_varying (&vr1); /* The resulting value range is the union of the operand ranges */ copy_value_range (vr, &vr0); vrp_meet (vr, &vr1); } /* Extract range information from a comparison expression EXPR based on the range of its operand and the expression code. */ static void extract_range_from_comparison (value_range *vr, enum tree_code code, tree type, tree op0, tree op1) { bool sop = false; tree val; val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop, NULL); /* A disadvantage of using a special infinity as an overflow representation is that we lose the ability to record overflow when we don't have an infinity. So we have to ignore a result which relies on overflow. */ if (val && !is_overflow_infinity (val) && !sop) { /* Since this expression was found on the RHS of an assignment, its type may be different from _Bool. Convert VAL to EXPR's type. */ val = fold_convert (type, val); if (is_gimple_min_invariant (val)) set_value_range_to_value (vr, val, vr->equiv); else set_value_range (vr, VR_RANGE, val, val, vr->equiv); } else /* The result of a comparison is always true or false. */ set_value_range_to_truthvalue (vr, type); } /* Helper function for simplify_internal_call_using_ranges and extract_range_basic. Return true if OP0 SUBCODE OP1 for SUBCODE {PLUS,MINUS,MULT}_EXPR is known to never overflow or always overflow. Set *OVF to true if it is known to always overflow. */ static bool check_for_binary_op_overflow (enum tree_code subcode, tree type, tree op0, tree op1, bool *ovf) { value_range vr0 = VR_INITIALIZER; value_range vr1 = VR_INITIALIZER; if (TREE_CODE (op0) == SSA_NAME) vr0 = *get_value_range (op0); else if (TREE_CODE (op0) == INTEGER_CST) set_value_range_to_value (&vr0, op0, NULL); else set_value_range_to_varying (&vr0); if (TREE_CODE (op1) == SSA_NAME) vr1 = *get_value_range (op1); else if (TREE_CODE (op1) == INTEGER_CST) set_value_range_to_value (&vr1, op1, NULL); else set_value_range_to_varying (&vr1); if (!range_int_cst_p (&vr0) || TREE_OVERFLOW (vr0.min) || TREE_OVERFLOW (vr0.max)) { vr0.min = vrp_val_min (TREE_TYPE (op0)); vr0.max = vrp_val_max (TREE_TYPE (op0)); } if (!range_int_cst_p (&vr1) || TREE_OVERFLOW (vr1.min) || TREE_OVERFLOW (vr1.max)) { vr1.min = vrp_val_min (TREE_TYPE (op1)); vr1.max = vrp_val_max (TREE_TYPE (op1)); } *ovf = arith_overflowed_p (subcode, type, vr0.min, subcode == MINUS_EXPR ? vr1.max : vr1.min); if (arith_overflowed_p (subcode, type, vr0.max, subcode == MINUS_EXPR ? vr1.min : vr1.max) != *ovf) return false; if (subcode == MULT_EXPR) { if (arith_overflowed_p (subcode, type, vr0.min, vr1.max) != *ovf || arith_overflowed_p (subcode, type, vr0.max, vr1.min) != *ovf) return false; } if (*ovf) { /* So far we found that there is an overflow on the boundaries. That doesn't prove that there is an overflow even for all values in between the boundaries. For that compute widest_int range of the result and see if it doesn't overlap the range of type. */ widest_int wmin, wmax; widest_int w[4]; int i; w[0] = wi::to_widest (vr0.min); w[1] = wi::to_widest (vr0.max); w[2] = wi::to_widest (vr1.min); w[3] = wi::to_widest (vr1.max); for (i = 0; i < 4; i++) { widest_int wt; switch (subcode) { case PLUS_EXPR: wt = wi::add (w[i & 1], w[2 + (i & 2) / 2]); break; case MINUS_EXPR: wt = wi::sub (w[i & 1], w[2 + (i & 2) / 2]); break; case MULT_EXPR: wt = wi::mul (w[i & 1], w[2 + (i & 2) / 2]); break; default: gcc_unreachable (); } if (i == 0) { wmin = wt; wmax = wt; } else { wmin = wi::smin (wmin, wt); wmax = wi::smax (wmax, wt); } } /* The result of op0 CODE op1 is known to be in range [wmin, wmax]. */ widest_int wtmin = wi::to_widest (vrp_val_min (type)); widest_int wtmax = wi::to_widest (vrp_val_max (type)); /* If all values in [wmin, wmax] are smaller than [wtmin, wtmax] or all are larger than [wtmin, wtmax], the arithmetic operation will always overflow. */ if (wmax < wtmin || wmin > wtmax) return true; return false; } return true; } /* Try to derive a nonnegative or nonzero range out of STMT relying primarily on generic routines in fold in conjunction with range data. Store the result in *VR */ static void extract_range_basic (value_range *vr, gimple *stmt) { bool sop = false; tree type = gimple_expr_type (stmt); if (is_gimple_call (stmt)) { tree arg; int mini, maxi, zerov = 0, prec; enum tree_code subcode = ERROR_MARK; combined_fn cfn = gimple_call_combined_fn (stmt); switch (cfn) { case CFN_BUILT_IN_CONSTANT_P: /* If the call is __builtin_constant_p and the argument is a function parameter resolve it to false. This avoids bogus array bound warnings. ??? We could do this as early as inlining is finished. */ arg = gimple_call_arg (stmt, 0); if (TREE_CODE (arg) == SSA_NAME && SSA_NAME_IS_DEFAULT_DEF (arg) && TREE_CODE (SSA_NAME_VAR (arg)) == PARM_DECL && cfun->after_inlining) { set_value_range_to_null (vr, type); return; } break; /* Both __builtin_ffs* and __builtin_popcount return [0, prec]. */ CASE_CFN_FFS: CASE_CFN_POPCOUNT: arg = gimple_call_arg (stmt, 0); prec = TYPE_PRECISION (TREE_TYPE (arg)); mini = 0; maxi = prec; if (TREE_CODE (arg) == SSA_NAME) { value_range *vr0 = get_value_range (arg); /* If arg is non-zero, then ffs or popcount are non-zero. */ if (((vr0->type == VR_RANGE && range_includes_zero_p (vr0->min, vr0->max) == 0) || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0->min, vr0->max) == 1)) && !is_overflow_infinity (vr0->min) && !is_overflow_infinity (vr0->max)) mini = 1; /* If some high bits are known to be zero, we can decrease the maximum. */ if (vr0->type == VR_RANGE && TREE_CODE (vr0->max) == INTEGER_CST && !operand_less_p (vr0->min, build_zero_cst (TREE_TYPE (vr0->min))) && !is_overflow_infinity (vr0->max)) maxi = tree_floor_log2 (vr0->max) + 1; } goto bitop_builtin; /* __builtin_parity* returns [0, 1]. */ CASE_CFN_PARITY: mini = 0; maxi = 1; goto bitop_builtin; /* __builtin_c[lt]z* return [0, prec-1], except for when the argument is 0, but that is undefined behavior. On many targets where the CLZ RTL or optab value is defined for 0 the value is prec, so include that in the range by default. */ CASE_CFN_CLZ: arg = gimple_call_arg (stmt, 0); prec = TYPE_PRECISION (TREE_TYPE (arg)); mini = 0; maxi = prec; if (optab_handler (clz_optab, TYPE_MODE (TREE_TYPE (arg))) != CODE_FOR_nothing && CLZ_DEFINED_VALUE_AT_ZERO (TYPE_MODE (TREE_TYPE (arg)), zerov) /* Handle only the single common value. */ && zerov != prec) /* Magic value to give up, unless vr0 proves arg is non-zero. */ mini = -2; if (TREE_CODE (arg) == SSA_NAME) { value_range *vr0 = get_value_range (arg); /* From clz of VR_RANGE minimum we can compute result maximum. */ if (vr0->type == VR_RANGE && TREE_CODE (vr0->min) == INTEGER_CST && !is_overflow_infinity (vr0->min)) { maxi = prec - 1 - tree_floor_log2 (vr0->min); if (maxi != prec) mini = 0; } else if (vr0->type == VR_ANTI_RANGE && integer_zerop (vr0->min) && !is_overflow_infinity (vr0->min)) { maxi = prec - 1; mini = 0; } if (mini == -2) break; /* From clz of VR_RANGE maximum we can compute result minimum. */ if (vr0->type == VR_RANGE && TREE_CODE (vr0->max) == INTEGER_CST && !is_overflow_infinity (vr0->max)) { mini = prec - 1 - tree_floor_log2 (vr0->max); if (mini == prec) break; } } if (mini == -2) break; goto bitop_builtin; /* __builtin_ctz* return [0, prec-1], except for when the argument is 0, but that is undefined behavior. If there is a ctz optab for this mode and CTZ_DEFINED_VALUE_AT_ZERO, include that in the range, otherwise just assume 0 won't be seen. */ CASE_CFN_CTZ: arg = gimple_call_arg (stmt, 0); prec = TYPE_PRECISION (TREE_TYPE (arg)); mini = 0; maxi = prec - 1; if (optab_handler (ctz_optab, TYPE_MODE (TREE_TYPE (arg))) != CODE_FOR_nothing && CTZ_DEFINED_VALUE_AT_ZERO (TYPE_MODE (TREE_TYPE (arg)), zerov)) { /* Handle only the two common values. */ if (zerov == -1) mini = -1; else if (zerov == prec) maxi = prec; else /* Magic value to give up, unless vr0 proves arg is non-zero. */ mini = -2; } if (TREE_CODE (arg) == SSA_NAME) { value_range *vr0 = get_value_range (arg); /* If arg is non-zero, then use [0, prec - 1]. */ if (((vr0->type == VR_RANGE && integer_nonzerop (vr0->min)) || (vr0->type == VR_ANTI_RANGE && integer_zerop (vr0->min))) && !is_overflow_infinity (vr0->min)) { mini = 0; maxi = prec - 1; } /* If some high bits are known to be zero, we can decrease the result maximum. */ if (vr0->type == VR_RANGE && TREE_CODE (vr0->max) == INTEGER_CST && !is_overflow_infinity (vr0->max)) { maxi = tree_floor_log2 (vr0->max); /* For vr0 [0, 0] give up. */ if (maxi == -1) break; } } if (mini == -2) break; goto bitop_builtin; /* __builtin_clrsb* returns [0, prec-1]. */ CASE_CFN_CLRSB: arg = gimple_call_arg (stmt, 0); prec = TYPE_PRECISION (TREE_TYPE (arg)); mini = 0; maxi = prec - 1; goto bitop_builtin; bitop_builtin: set_value_range (vr, VR_RANGE, build_int_cst (type, mini), build_int_cst (type, maxi), NULL); return; case CFN_UBSAN_CHECK_ADD: subcode = PLUS_EXPR; break; case CFN_UBSAN_CHECK_SUB: subcode = MINUS_EXPR; break; case CFN_UBSAN_CHECK_MUL: subcode = MULT_EXPR; break; case CFN_GOACC_DIM_SIZE: case CFN_GOACC_DIM_POS: /* Optimizing these two internal functions helps the loop optimizer eliminate outer comparisons. Size is [1,N] and pos is [0,N-1]. */ { bool is_pos = cfn == CFN_GOACC_DIM_POS; int axis = get_oacc_ifn_dim_arg (stmt); int size = get_oacc_fn_dim_size (current_function_decl, axis); if (!size) /* If it's dynamic, the backend might know a hardware limitation. */ size = targetm.goacc.dim_limit (axis); tree type = TREE_TYPE (gimple_call_lhs (stmt)); set_value_range (vr, VR_RANGE, build_int_cst (type, is_pos ? 0 : 1), size ? build_int_cst (type, size - is_pos) : vrp_val_max (type), NULL); } return; default: break; } if (subcode != ERROR_MARK) { bool saved_flag_wrapv = flag_wrapv; /* Pretend the arithmetics is wrapping. If there is any overflow, we'll complain, but will actually do wrapping operation. */ flag_wrapv = 1; extract_range_from_binary_expr (vr, subcode, type, gimple_call_arg (stmt, 0), gimple_call_arg (stmt, 1)); flag_wrapv = saved_flag_wrapv; /* If for both arguments vrp_valueize returned non-NULL, this should have been already folded and if not, it wasn't folded because of overflow. Avoid removing the UBSAN_CHECK_* calls in that case. */ if (vr->type == VR_RANGE && (vr->min == vr->max || operand_equal_p (vr->min, vr->max, 0))) set_value_range_to_varying (vr); return; } } /* Handle extraction of the two results (result of arithmetics and a flag whether arithmetics overflowed) from {ADD,SUB,MUL}_OVERFLOW internal function. */ else if (is_gimple_assign (stmt) && (gimple_assign_rhs_code (stmt) == REALPART_EXPR || gimple_assign_rhs_code (stmt) == IMAGPART_EXPR) && INTEGRAL_TYPE_P (type)) { enum tree_code code = gimple_assign_rhs_code (stmt); tree op = gimple_assign_rhs1 (stmt); if (TREE_CODE (op) == code && TREE_CODE (TREE_OPERAND (op, 0)) == SSA_NAME) { gimple *g = SSA_NAME_DEF_STMT (TREE_OPERAND (op, 0)); if (is_gimple_call (g) && gimple_call_internal_p (g)) { enum tree_code subcode = ERROR_MARK; switch (gimple_call_internal_fn (g)) { case IFN_ADD_OVERFLOW: subcode = PLUS_EXPR; break; case IFN_SUB_OVERFLOW: subcode = MINUS_EXPR; break; case IFN_MUL_OVERFLOW: subcode = MULT_EXPR; break; default: break; } if (subcode != ERROR_MARK) { tree op0 = gimple_call_arg (g, 0); tree op1 = gimple_call_arg (g, 1); if (code == IMAGPART_EXPR) { bool ovf = false; if (check_for_binary_op_overflow (subcode, type, op0, op1, &ovf)) set_value_range_to_value (vr, build_int_cst (type, ovf), NULL); else if (TYPE_PRECISION (type) == 1 && !TYPE_UNSIGNED (type)) set_value_range_to_varying (vr); else set_value_range (vr, VR_RANGE, build_int_cst (type, 0), build_int_cst (type, 1), NULL); } else if (types_compatible_p (type, TREE_TYPE (op0)) && types_compatible_p (type, TREE_TYPE (op1))) { bool saved_flag_wrapv = flag_wrapv; /* Pretend the arithmetics is wrapping. If there is any overflow, IMAGPART_EXPR will be set. */ flag_wrapv = 1; extract_range_from_binary_expr (vr, subcode, type, op0, op1); flag_wrapv = saved_flag_wrapv; } else { value_range vr0 = VR_INITIALIZER; value_range vr1 = VR_INITIALIZER; bool saved_flag_wrapv = flag_wrapv; /* Pretend the arithmetics is wrapping. If there is any overflow, IMAGPART_EXPR will be set. */ flag_wrapv = 1; extract_range_from_unary_expr (&vr0, NOP_EXPR, type, op0); extract_range_from_unary_expr (&vr1, NOP_EXPR, type, op1); extract_range_from_binary_expr_1 (vr, subcode, type, &vr0, &vr1); flag_wrapv = saved_flag_wrapv; } return; } } } } if (INTEGRAL_TYPE_P (type) && gimple_stmt_nonnegative_warnv_p (stmt, &sop)) set_value_range_to_nonnegative (vr, type, sop || stmt_overflow_infinity (stmt)); else if (vrp_stmt_computes_nonzero (stmt, &sop) && !sop) set_value_range_to_nonnull (vr, type); else set_value_range_to_varying (vr); } /* Try to compute a useful range out of assignment STMT and store it in *VR. */ static void extract_range_from_assignment (value_range *vr, gassign *stmt) { enum tree_code code = gimple_assign_rhs_code (stmt); if (code == ASSERT_EXPR) extract_range_from_assert (vr, gimple_assign_rhs1 (stmt)); else if (code == SSA_NAME) extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt)); else if (TREE_CODE_CLASS (code) == tcc_binary) extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt), gimple_expr_type (stmt), gimple_assign_rhs1 (stmt), gimple_assign_rhs2 (stmt)); else if (TREE_CODE_CLASS (code) == tcc_unary) extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt), gimple_expr_type (stmt), gimple_assign_rhs1 (stmt)); else if (code == COND_EXPR) extract_range_from_cond_expr (vr, stmt); else if (TREE_CODE_CLASS (code) == tcc_comparison) extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt), gimple_expr_type (stmt), gimple_assign_rhs1 (stmt), gimple_assign_rhs2 (stmt)); else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS && is_gimple_min_invariant (gimple_assign_rhs1 (stmt))) set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL); else set_value_range_to_varying (vr); if (vr->type == VR_VARYING) extract_range_basic (vr, stmt); } /* Given a range VR, a LOOP and a variable VAR, determine whether it would be profitable to adjust VR using scalar evolution information for VAR. If so, update VR with the new limits. */ static void adjust_range_with_scev (value_range *vr, struct loop *loop, gimple *stmt, tree var) { tree init, step, chrec, tmin, tmax, min, max, type, tem; enum ev_direction dir; /* TODO. Don't adjust anti-ranges. An anti-range may provide better opportunities than a regular range, but I'm not sure. */ if (vr->type == VR_ANTI_RANGE) return; chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var)); /* Like in PR19590, scev can return a constant function. */ if (is_gimple_min_invariant (chrec)) { set_value_range_to_value (vr, chrec, vr->equiv); return; } if (TREE_CODE (chrec) != POLYNOMIAL_CHREC) return; init = initial_condition_in_loop_num (chrec, loop->num); tem = op_with_constant_singleton_value_range (init); if (tem) init = tem; step = evolution_part_in_loop_num (chrec, loop->num); tem = op_with_constant_singleton_value_range (step); if (tem) step = tem; /* If STEP is symbolic, we can't know whether INIT will be the minimum or maximum value in the range. Also, unless INIT is a simple expression, compare_values and possibly other functions in tree-vrp won't be able to handle it. */ if (step == NULL_TREE || !is_gimple_min_invariant (step) || !valid_value_p (init)) return; dir = scev_direction (chrec); if (/* Do not adjust ranges if we do not know whether the iv increases or decreases, ... */ dir == EV_DIR_UNKNOWN /* ... or if it may wrap. */ || scev_probably_wraps_p (NULL_TREE, init, step, stmt, get_chrec_loop (chrec), true)) return; /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of negative_overflow_infinity and positive_overflow_infinity, because we have concluded that the loop probably does not wrap. */ type = TREE_TYPE (var); if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type)) tmin = lower_bound_in_type (type, type); else tmin = TYPE_MIN_VALUE (type); if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type)) tmax = upper_bound_in_type (type, type); else tmax = TYPE_MAX_VALUE (type); /* Try to use estimated number of iterations for the loop to constrain the final value in the evolution. */ if (TREE_CODE (step) == INTEGER_CST && is_gimple_val (init) && (TREE_CODE (init) != SSA_NAME || get_value_range (init)->type == VR_RANGE)) { widest_int nit; /* We are only entering here for loop header PHI nodes, so using the number of latch executions is the correct thing to use. */ if (max_loop_iterations (loop, &nit)) { value_range maxvr = VR_INITIALIZER; signop sgn = TYPE_SIGN (TREE_TYPE (step)); bool overflow; widest_int wtmp = wi::mul (wi::to_widest (step), nit, sgn, &overflow); /* If the multiplication overflowed we can't do a meaningful adjustment. Likewise if the result doesn't fit in the type of the induction variable. For a signed type we have to check whether the result has the expected signedness which is that of the step as number of iterations is unsigned. */ if (!overflow && wi::fits_to_tree_p (wtmp, TREE_TYPE (init)) && (sgn == UNSIGNED || wi::gts_p (wtmp, 0) == wi::gts_p (step, 0))) { tem = wide_int_to_tree (TREE_TYPE (init), wtmp); extract_range_from_binary_expr (&maxvr, PLUS_EXPR, TREE_TYPE (init), init, tem); /* Likewise if the addition did. */ if (maxvr.type == VR_RANGE) { value_range initvr = VR_INITIALIZER; if (TREE_CODE (init) == SSA_NAME) initvr = *(get_value_range (init)); else if (is_gimple_min_invariant (init)) set_value_range_to_value (&initvr, init, NULL); else return; /* Check if init + nit * step overflows. Though we checked scev {init, step}_loop doesn't wrap, it is not enough because the loop may exit immediately. Overflow could happen in the plus expression in this case. */ if ((dir == EV_DIR_DECREASES && (is_negative_overflow_infinity (maxvr.min) || compare_values (maxvr.min, initvr.min) != -1)) || (dir == EV_DIR_GROWS && (is_positive_overflow_infinity (maxvr.max) || compare_values (maxvr.max, initvr.max) != 1))) return; tmin = maxvr.min; tmax = maxvr.max; } } } } if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED) { min = tmin; max = tmax; /* For VARYING or UNDEFINED ranges, just about anything we get from scalar evolutions should be better. */ if (dir == EV_DIR_DECREASES) max = init; else min = init; } else if (vr->type == VR_RANGE) { min = vr->min; max = vr->max; if (dir == EV_DIR_DECREASES) { /* INIT is the maximum value. If INIT is lower than VR->MAX but no smaller than VR->MIN, set VR->MAX to INIT. */ if (compare_values (init, max) == -1) max = init; /* According to the loop information, the variable does not overflow. If we think it does, probably because of an overflow due to arithmetic on a different INF value, reset now. */ if (is_negative_overflow_infinity (min) || compare_values (min, tmin) == -1) min = tmin; } else { /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */ if (compare_values (init, min) == 1) min = init; if (is_positive_overflow_infinity (max) || compare_values (tmax, max) == -1) max = tmax; } } else return; /* If we just created an invalid range with the minimum greater than the maximum, we fail conservatively. This should happen only in unreachable parts of code, or for invalid programs. */ if (compare_values (min, max) == 1 || (is_negative_overflow_infinity (min) && is_positive_overflow_infinity (max))) return; /* Even for valid range info, sometimes overflow flag will leak in. As GIMPLE IL should have no constants with TREE_OVERFLOW set, we drop them except for +-overflow_infinity which still need special handling in vrp pass. */ if (TREE_OVERFLOW_P (min) && ! is_negative_overflow_infinity (min)) min = drop_tree_overflow (min); if (TREE_OVERFLOW_P (max) && ! is_positive_overflow_infinity (max)) max = drop_tree_overflow (max); set_value_range (vr, VR_RANGE, min, max, vr->equiv); } /* Given two numeric value ranges VR0, VR1 and a comparison code COMP: - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for all the values in the ranges. - Return BOOLEAN_FALSE_NODE if the comparison always returns false. - Return NULL_TREE if it is not always possible to determine the value of the comparison. Also set *STRICT_OVERFLOW_P to indicate whether a range with an overflow infinity was used in the test. */ static tree compare_ranges (enum tree_code comp, value_range *vr0, value_range *vr1, bool *strict_overflow_p) { /* VARYING or UNDEFINED ranges cannot be compared. */ if (vr0->type == VR_VARYING || vr0->type == VR_UNDEFINED || vr1->type == VR_VARYING || vr1->type == VR_UNDEFINED) return NULL_TREE; /* Anti-ranges need to be handled separately. */ if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE) { /* If both are anti-ranges, then we cannot compute any comparison. */ if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE) return NULL_TREE; /* These comparisons are never statically computable. */ if (comp == GT_EXPR || comp == GE_EXPR || comp == LT_EXPR || comp == LE_EXPR) return NULL_TREE; /* Equality can be computed only between a range and an anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */ if (vr0->type == VR_RANGE) { /* To simplify processing, make VR0 the anti-range. */ value_range *tmp = vr0; vr0 = vr1; vr1 = tmp; } gcc_assert (comp == NE_EXPR || comp == EQ_EXPR); if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0) return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node; return NULL_TREE; } if (!usable_range_p (vr0, strict_overflow_p) || !usable_range_p (vr1, strict_overflow_p)) return NULL_TREE; /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the operands around and change the comparison code. */ if (comp == GT_EXPR || comp == GE_EXPR) { comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR; std::swap (vr0, vr1); } if (comp == EQ_EXPR) { /* Equality may only be computed if both ranges represent exactly one value. */ if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0) { int cmp_min = compare_values_warnv (vr0->min, vr1->min, strict_overflow_p); int cmp_max = compare_values_warnv (vr0->max, vr1->max, strict_overflow_p); if (cmp_min == 0 && cmp_max == 0) return boolean_true_node; else if (cmp_min != -2 && cmp_max != -2) return boolean_false_node; } /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */ else if (compare_values_warnv (vr0->min, vr1->max, strict_overflow_p) == 1 || compare_values_warnv (vr1->min, vr0->max, strict_overflow_p) == 1) return boolean_false_node; return NULL_TREE; } else if (comp == NE_EXPR) { int cmp1, cmp2; /* If VR0 is completely to the left or completely to the right of VR1, they are always different. Notice that we need to make sure that both comparisons yield similar results to avoid comparing values that cannot be compared at compile-time. */ cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p); cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p); if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1)) return boolean_true_node; /* If VR0 and VR1 represent a single value and are identical, return false. */ else if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0 && compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0) return boolean_false_node; /* Otherwise, they may or may not be different. */ else return NULL_TREE; } else if (comp == LT_EXPR || comp == LE_EXPR) { int tst; /* If VR0 is to the left of VR1, return true. */ tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p); if ((comp == LT_EXPR && tst == -1) || (comp == LE_EXPR && (tst == -1 || tst == 0))) { if (overflow_infinity_range_p (vr0) || overflow_infinity_range_p (vr1)) *strict_overflow_p = true; return boolean_true_node; } /* If VR0 is to the right of VR1, return false. */ tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p); if ((comp == LT_EXPR && (tst == 0 || tst == 1)) || (comp == LE_EXPR && tst == 1)) { if (overflow_infinity_range_p (vr0) || overflow_infinity_range_p (vr1)) *strict_overflow_p = true; return boolean_false_node; } /* Otherwise, we don't know. */ return NULL_TREE; } gcc_unreachable (); } /* Given a value range VR, a value VAL and a comparison code COMP, return BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the values in VR. Return BOOLEAN_FALSE_NODE if the comparison always returns false. Return NULL_TREE if it is not always possible to determine the value of the comparison. Also set *STRICT_OVERFLOW_P to indicate whether a range with an overflow infinity was used in the test. */ static tree compare_range_with_value (enum tree_code comp, value_range *vr, tree val, bool *strict_overflow_p) { if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED) return NULL_TREE; /* Anti-ranges need to be handled separately. */ if (vr->type == VR_ANTI_RANGE) { /* For anti-ranges, the only predicates that we can compute at compile time are equality and inequality. */ if (comp == GT_EXPR || comp == GE_EXPR || comp == LT_EXPR || comp == LE_EXPR) return NULL_TREE; /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */ if (value_inside_range (val, vr->min, vr->max) == 1) return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node; return NULL_TREE; } if (!usable_range_p (vr, strict_overflow_p)) return NULL_TREE; if (comp == EQ_EXPR) { /* EQ_EXPR may only be computed if VR represents exactly one value. */ if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0) { int cmp = compare_values_warnv (vr->min, val, strict_overflow_p); if (cmp == 0) return boolean_true_node; else if (cmp == -1 || cmp == 1 || cmp == 2) return boolean_false_node; } else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1) return boolean_false_node; return NULL_TREE; } else if (comp == NE_EXPR) { /* If VAL is not inside VR, then they are always different. */ if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1) return boolean_true_node; /* If VR represents exactly one value equal to VAL, then return false. */ if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0) return boolean_false_node; /* Otherwise, they may or may not be different. */ return NULL_TREE; } else if (comp == LT_EXPR || comp == LE_EXPR) { int tst; /* If VR is to the left of VAL, return true. */ tst = compare_values_warnv (vr->max, val, strict_overflow_p); if ((comp == LT_EXPR && tst == -1) || (comp == LE_EXPR && (tst == -1 || tst == 0))) { if (overflow_infinity_range_p (vr)) *strict_overflow_p = true; return boolean_true_node; } /* If VR is to the right of VAL, return false. */ tst = compare_values_warnv (vr->min, val, strict_overflow_p); if ((comp == LT_EXPR && (tst == 0 || tst == 1)) || (comp == LE_EXPR && tst == 1)) { if (overflow_infinity_range_p (vr)) *strict_overflow_p = true; return boolean_false_node; } /* Otherwise, we don't know. */ return NULL_TREE; } else if (comp == GT_EXPR || comp == GE_EXPR) { int tst; /* If VR is to the right of VAL, return true. */ tst = compare_values_warnv (vr->min, val, strict_overflow_p); if ((comp == GT_EXPR && tst == 1) || (comp == GE_EXPR && (tst == 0 || tst == 1))) { if (overflow_infinity_range_p (vr)) *strict_overflow_p = true; return boolean_true_node; } /* If VR is to the left of VAL, return false. */ tst = compare_values_warnv (vr->max, val, strict_overflow_p); if ((comp == GT_EXPR && (tst == -1 || tst == 0)) || (comp == GE_EXPR && tst == -1)) { if (overflow_infinity_range_p (vr)) *strict_overflow_p = true; return boolean_false_node; } /* Otherwise, we don't know. */ return NULL_TREE; } gcc_unreachable (); } /* Debugging dumps. */ void dump_value_range (FILE *, const value_range *); void debug_value_range (value_range *); void dump_all_value_ranges (FILE *); void debug_all_value_ranges (void); void dump_vr_equiv (FILE *, bitmap); void debug_vr_equiv (bitmap); /* Dump value range VR to FILE. */ void dump_value_range (FILE *file, const value_range *vr) { if (vr == NULL) fprintf (file, "[]"); else if (vr->type == VR_UNDEFINED) fprintf (file, "UNDEFINED"); else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE) { tree type = TREE_TYPE (vr->min); fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : ""); if (is_negative_overflow_infinity (vr->min)) fprintf (file, "-INF(OVF)"); else if (INTEGRAL_TYPE_P (type) && !TYPE_UNSIGNED (type) && vrp_val_is_min (vr->min)) fprintf (file, "-INF"); else print_generic_expr (file, vr->min, 0); fprintf (file, ", "); if (is_positive_overflow_infinity (vr->max)) fprintf (file, "+INF(OVF)"); else if (INTEGRAL_TYPE_P (type) && vrp_val_is_max (vr->max)) fprintf (file, "+INF"); else print_generic_expr (file, vr->max, 0); fprintf (file, "]"); if (vr->equiv) { bitmap_iterator bi; unsigned i, c = 0; fprintf (file, " EQUIVALENCES: { "); EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi) { print_generic_expr (file, ssa_name (i), 0); fprintf (file, " "); c++; } fprintf (file, "} (%u elements)", c); } } else if (vr->type == VR_VARYING) fprintf (file, "VARYING"); else fprintf (file, "INVALID RANGE"); } /* Dump value range VR to stderr. */ DEBUG_FUNCTION void debug_value_range (value_range *vr) { dump_value_range (stderr, vr); fprintf (stderr, "\n"); } /* Dump value ranges of all SSA_NAMEs to FILE. */ void dump_all_value_ranges (FILE *file) { size_t i; for (i = 0; i < num_vr_values; i++) { if (vr_value[i]) { print_generic_expr (file, ssa_name (i), 0); fprintf (file, ": "); dump_value_range (file, vr_value[i]); fprintf (file, "\n"); } } fprintf (file, "\n"); } /* Dump all value ranges to stderr. */ DEBUG_FUNCTION void debug_all_value_ranges (void) { dump_all_value_ranges (stderr); } /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V, create a new SSA name N and return the assertion assignment 'N = ASSERT_EXPR <V, V OP W>'. */ static gimple * build_assert_expr_for (tree cond, tree v) { tree a; gassign *assertion; gcc_assert (TREE_CODE (v) == SSA_NAME && COMPARISON_CLASS_P (cond)); a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond); assertion = gimple_build_assign (NULL_TREE, a); /* The new ASSERT_EXPR, creates a new SSA name that replaces the operand of the ASSERT_EXPR. Create it so the new name and the old one are registered in the replacement table so that we can fix the SSA web after adding all the ASSERT_EXPRs. */ create_new_def_for (v, assertion, NULL); return assertion; } /* Return false if EXPR is a predicate expression involving floating point values. */ static inline bool fp_predicate (gimple *stmt) { GIMPLE_CHECK (stmt, GIMPLE_COND); return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt))); } /* If the range of values taken by OP can be inferred after STMT executes, return the comparison code (COMP_CODE_P) and value (VAL_P) that describes the inferred range. Return true if a range could be inferred. */ static bool infer_value_range (gimple *stmt, tree op, tree_code *comp_code_p, tree *val_p) { *val_p = NULL_TREE; *comp_code_p = ERROR_MARK; /* Do not attempt to infer anything in names that flow through abnormal edges. */ if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op)) return false; /* If STMT is the last statement of a basic block with no normal successors, there is no point inferring anything about any of its operands. We would not be able to find a proper insertion point for the assertion, anyway. */ if (stmt_ends_bb_p (stmt)) { edge_iterator ei; edge e; FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs) if (!(e->flags & (EDGE_ABNORMAL|EDGE_EH))) break; if (e == NULL) return false; } if (infer_nonnull_range (stmt, op)) { *val_p = build_int_cst (TREE_TYPE (op), 0); *comp_code_p = NE_EXPR; return true; } return false; } void dump_asserts_for (FILE *, tree); void debug_asserts_for (tree); void dump_all_asserts (FILE *); void debug_all_asserts (void); /* Dump all the registered assertions for NAME to FILE. */ void dump_asserts_for (FILE *file, tree name) { assert_locus *loc; fprintf (file, "Assertions to be inserted for "); print_generic_expr (file, name, 0); fprintf (file, "\n"); loc = asserts_for[SSA_NAME_VERSION (name)]; while (loc) { fprintf (file, "\t"); print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0); fprintf (file, "\n\tBB #%d", loc->bb->index); if (loc->e) { fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index, loc->e->dest->index); dump_edge_info (file, loc->e, dump_flags, 0); } fprintf (file, "\n\tPREDICATE: "); print_generic_expr (file, loc->expr, 0); fprintf (file, " %s ", get_tree_code_name (loc->comp_code)); print_generic_expr (file, loc->val, 0); fprintf (file, "\n\n"); loc = loc->next; } fprintf (file, "\n"); } /* Dump all the registered assertions for NAME to stderr. */ DEBUG_FUNCTION void debug_asserts_for (tree name) { dump_asserts_for (stderr, name); } /* Dump all the registered assertions for all the names to FILE. */ void dump_all_asserts (FILE *file) { unsigned i; bitmap_iterator bi; fprintf (file, "\nASSERT_EXPRs to be inserted\n\n"); EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi) dump_asserts_for (file, ssa_name (i)); fprintf (file, "\n"); } /* Dump all the registered assertions for all the names to stderr. */ DEBUG_FUNCTION void debug_all_asserts (void) { dump_all_asserts (stderr); } /* If NAME doesn't have an ASSERT_EXPR registered for asserting 'EXPR COMP_CODE VAL' at a location that dominates block BB or E->DEST, then register this location as a possible insertion point for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>. BB, E and SI provide the exact insertion point for the new ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E must not be NULL. */ static void register_new_assert_for (tree name, tree expr, enum tree_code comp_code, tree val, basic_block bb, edge e, gimple_stmt_iterator si) { assert_locus *n, *loc, *last_loc; basic_block dest_bb; gcc_checking_assert (bb == NULL || e == NULL); if (e == NULL) gcc_checking_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH); /* Never build an assert comparing against an integer constant with TREE_OVERFLOW set. This confuses our undefined overflow warning machinery. */ if (TREE_OVERFLOW_P (val)) val = drop_tree_overflow (val); /* The new assertion A will be inserted at BB or E. We need to determine if the new location is dominated by a previously registered location for A. If we are doing an edge insertion, assume that A will be inserted at E->DEST. Note that this is not necessarily true. If E is a critical edge, it will be split. But even if E is split, the new block will dominate the same set of blocks that E->DEST dominates. The reverse, however, is not true, blocks dominated by E->DEST will not be dominated by the new block created to split E. So, if the insertion location is on a critical edge, we will not use the new location to move another assertion previously registered at a block dominated by E->DEST. */ dest_bb = (bb) ? bb : e->dest; /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and VAL at a block dominating DEST_BB, then we don't need to insert a new one. Similarly, if the same assertion already exists at a block dominated by DEST_BB and the new location is not on a critical edge, then update the existing location for the assertion (i.e., move the assertion up in the dominance tree). Note, this is implemented as a simple linked list because there should not be more than a handful of assertions registered per name. If this becomes a performance problem, a table hashed by COMP_CODE and VAL could be implemented. */ loc = asserts_for[SSA_NAME_VERSION (name)]; last_loc = loc; while (loc) { if (loc->comp_code == comp_code && (loc->val == val || operand_equal_p (loc->val, val, 0)) && (loc->expr == expr || operand_equal_p (loc->expr, expr, 0))) { /* If E is not a critical edge and DEST_BB dominates the existing location for the assertion, move the assertion up in the dominance tree by updating its location information. */ if ((e == NULL || !EDGE_CRITICAL_P (e)) && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb)) { loc->bb = dest_bb; loc->e = e; loc->si = si; return; } } /* Update the last node of the list and move to the next one. */ last_loc = loc; loc = loc->next; } /* If we didn't find an assertion already registered for NAME COMP_CODE VAL, add a new one at the end of the list of assertions associated with NAME. */ n = XNEW (struct assert_locus); n->bb = dest_bb; n->e = e; n->si = si; n->comp_code = comp_code; n->val = val; n->expr = expr; n->next = NULL; if (last_loc) last_loc->next = n; else asserts_for[SSA_NAME_VERSION (name)] = n; bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name)); } /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME. Extract a suitable test code and value and store them into *CODE_P and *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P. If no extraction was possible, return FALSE, otherwise return TRUE. If INVERT is true, then we invert the result stored into *CODE_P. */ static bool extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code, tree cond_op0, tree cond_op1, bool invert, enum tree_code *code_p, tree *val_p) { enum tree_code comp_code; tree val; /* Otherwise, we have a comparison of the form NAME COMP VAL or VAL COMP NAME. */ if (name == cond_op1) { /* If the predicate is of the form VAL COMP NAME, flip COMP around because we need to register NAME as the first operand in the predicate. */ comp_code = swap_tree_comparison (cond_code); val = cond_op0; } else if (name == cond_op0) { /* The comparison is of the form NAME COMP VAL, so the comparison code remains unchanged. */ comp_code = cond_code; val = cond_op1; } else gcc_unreachable (); /* Invert the comparison code as necessary. */ if (invert) comp_code = invert_tree_comparison (comp_code, 0); /* VRP only handles integral and pointer types. */ if (! INTEGRAL_TYPE_P (TREE_TYPE (val)) && ! POINTER_TYPE_P (TREE_TYPE (val))) return false; /* Do not register always-false predicates. FIXME: this works around a limitation in fold() when dealing with enumerations. Given 'enum { N1, N2 } x;', fold will not fold 'if (x > N2)' to 'if (0)'. */ if ((comp_code == GT_EXPR || comp_code == LT_EXPR) && INTEGRAL_TYPE_P (TREE_TYPE (val))) { tree min = TYPE_MIN_VALUE (TREE_TYPE (val)); tree max = TYPE_MAX_VALUE (TREE_TYPE (val)); if (comp_code == GT_EXPR && (!max || compare_values (val, max) == 0)) return false; if (comp_code == LT_EXPR && (!min || compare_values (val, min) == 0)) return false; } *code_p = comp_code; *val_p = val; return true; } /* Find out smallest RES where RES > VAL && (RES & MASK) == RES, if any (otherwise return VAL). VAL and MASK must be zero-extended for precision PREC. If SGNBIT is non-zero, first xor VAL with SGNBIT (to transform signed values into unsigned) and at the end xor SGNBIT back. */ static wide_int masked_increment (const wide_int &val_in, const wide_int &mask, const wide_int &sgnbit, unsigned int prec) { wide_int bit = wi::one (prec), res; unsigned int i; wide_int val = val_in ^ sgnbit; for (i = 0; i < prec; i++, bit += bit) { res = mask; if ((res & bit) == 0) continue; res = bit - 1; res = (val + bit).and_not (res); res &= mask; if (wi::gtu_p (res, val)) return res ^ sgnbit; } return val ^ sgnbit; } /* Try to register an edge assertion for SSA name NAME on edge E for the condition COND contributing to the conditional jump pointed to by BSI. Invert the condition COND if INVERT is true. */ static void register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi, enum tree_code cond_code, tree cond_op0, tree cond_op1, bool invert) { tree val; enum tree_code comp_code; if (!extract_code_and_val_from_cond_with_ops (name, cond_code, cond_op0, cond_op1, invert, &comp_code, &val)) return; /* Only register an ASSERT_EXPR if NAME was found in the sub-graph reachable from E. */ if (live_on_edge (e, name)) register_new_assert_for (name, name, comp_code, val, NULL, e, bsi); /* In the case of NAME <= CST and NAME being defined as NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2 and NAME2 <= CST - CST2. We can do the same for NAME > CST. This catches range and anti-range tests. */ if ((comp_code == LE_EXPR || comp_code == GT_EXPR) && TREE_CODE (val) == INTEGER_CST && TYPE_UNSIGNED (TREE_TYPE (val))) { gimple *def_stmt = SSA_NAME_DEF_STMT (name); tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE; /* Extract CST2 from the (optional) addition. */ if (is_gimple_assign (def_stmt) && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR) { name2 = gimple_assign_rhs1 (def_stmt); cst2 = gimple_assign_rhs2 (def_stmt); if (TREE_CODE (name2) == SSA_NAME && TREE_CODE (cst2) == INTEGER_CST) def_stmt = SSA_NAME_DEF_STMT (name2); } /* Extract NAME2 from the (optional) sign-changing cast. */ if (gimple_assign_cast_p (def_stmt)) { if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)) && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt))) && (TYPE_PRECISION (gimple_expr_type (def_stmt)) == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))) name3 = gimple_assign_rhs1 (def_stmt); } /* If name3 is used later, create an ASSERT_EXPR for it. */ if (name3 != NULL_TREE && TREE_CODE (name3) == SSA_NAME && (cst2 == NULL_TREE || TREE_CODE (cst2) == INTEGER_CST) && INTEGRAL_TYPE_P (TREE_TYPE (name3)) && live_on_edge (e, name3)) { tree tmp; /* Build an expression for the range test. */ tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3); if (cst2 != NULL_TREE) tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2); if (dump_file) { fprintf (dump_file, "Adding assert for "); print_generic_expr (dump_file, name3, 0); fprintf (dump_file, " from "); print_generic_expr (dump_file, tmp, 0); fprintf (dump_file, "\n"); } register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi); } /* If name2 is used later, create an ASSERT_EXPR for it. */ if (name2 != NULL_TREE && TREE_CODE (name2) == SSA_NAME && TREE_CODE (cst2) == INTEGER_CST && INTEGRAL_TYPE_P (TREE_TYPE (name2)) && live_on_edge (e, name2)) { tree tmp; /* Build an expression for the range test. */ tmp = name2; if (TREE_TYPE (name) != TREE_TYPE (name2)) tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp); if (cst2 != NULL_TREE) tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2); if (dump_file) { fprintf (dump_file, "Adding assert for "); print_generic_expr (dump_file, name2, 0); fprintf (dump_file, " from "); print_generic_expr (dump_file, tmp, 0); fprintf (dump_file, "\n"); } register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi); } } /* In the case of post-in/decrement tests like if (i++) ... and uses of the in/decremented value on the edge the extra name we want to assert for is not on the def chain of the name compared. Instead it is in the set of use stmts. Similar cases happen for conversions that were simplified through fold_{sign_changed,widened}_comparison. */ if ((comp_code == NE_EXPR || comp_code == EQ_EXPR) && TREE_CODE (val) == INTEGER_CST) { imm_use_iterator ui; gimple *use_stmt; FOR_EACH_IMM_USE_STMT (use_stmt, ui, name) { if (!is_gimple_assign (use_stmt)) continue; /* Cut off to use-stmts that are dominating the predecessor. */ if (!dominated_by_p (CDI_DOMINATORS, e->src, gimple_bb (use_stmt))) continue; tree name2 = gimple_assign_lhs (use_stmt); if (TREE_CODE (name2) != SSA_NAME || !live_on_edge (e, name2)) continue; enum tree_code code = gimple_assign_rhs_code (use_stmt); tree cst; if (code == PLUS_EXPR || code == MINUS_EXPR) { cst = gimple_assign_rhs2 (use_stmt); if (TREE_CODE (cst) != INTEGER_CST) continue; cst = int_const_binop (code, val, cst); } else if (CONVERT_EXPR_CODE_P (code)) { /* For truncating conversions we cannot record an inequality. */ if (comp_code == NE_EXPR && (TYPE_PRECISION (TREE_TYPE (name2)) < TYPE_PRECISION (TREE_TYPE (name)))) continue; cst = fold_convert (TREE_TYPE (name2), val); } else continue; if (TREE_OVERFLOW_P (cst)) cst = drop_tree_overflow (cst); register_new_assert_for (name2, name2, comp_code, cst, NULL, e, bsi); } } if (TREE_CODE_CLASS (comp_code) == tcc_comparison && TREE_CODE (val) == INTEGER_CST) { gimple *def_stmt = SSA_NAME_DEF_STMT (name); tree name2 = NULL_TREE, names[2], cst2 = NULL_TREE; tree val2 = NULL_TREE; unsigned int prec = TYPE_PRECISION (TREE_TYPE (val)); wide_int mask = wi::zero (prec); unsigned int nprec = prec; enum tree_code rhs_code = ERROR_MARK; if (is_gimple_assign (def_stmt)) rhs_code = gimple_assign_rhs_code (def_stmt); /* In the case of NAME != CST1 where NAME = A +- CST2 we can assert that A != CST1 -+ CST2. */ if ((comp_code == EQ_EXPR || comp_code == NE_EXPR) && (rhs_code == PLUS_EXPR || rhs_code == MINUS_EXPR)) { tree op0 = gimple_assign_rhs1 (def_stmt); tree op1 = gimple_assign_rhs2 (def_stmt); if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == INTEGER_CST && live_on_edge (e, op0)) { enum tree_code reverse_op = (rhs_code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR); op1 = int_const_binop (reverse_op, val, op1); if (TREE_OVERFLOW (op1)) op1 = drop_tree_overflow (op1); register_new_assert_for (op0, op0, comp_code, op1, NULL, e, bsi); } } /* Add asserts for NAME cmp CST and NAME being defined as NAME = (int) NAME2. */ if (!TYPE_UNSIGNED (TREE_TYPE (val)) && (comp_code == LE_EXPR || comp_code == LT_EXPR || comp_code == GT_EXPR || comp_code == GE_EXPR) && gimple_assign_cast_p (def_stmt)) { name2 = gimple_assign_rhs1 (def_stmt); if (CONVERT_EXPR_CODE_P (rhs_code) && INTEGRAL_TYPE_P (TREE_TYPE (name2)) && TYPE_UNSIGNED (TREE_TYPE (name2)) && prec == TYPE_PRECISION (TREE_TYPE (name2)) && (comp_code == LE_EXPR || comp_code == GT_EXPR || !tree_int_cst_equal (val, TYPE_MIN_VALUE (TREE_TYPE (val)))) && live_on_edge (e, name2)) { tree tmp, cst; enum tree_code new_comp_code = comp_code; cst = fold_convert (TREE_TYPE (name2), TYPE_MIN_VALUE (TREE_TYPE (val))); /* Build an expression for the range test. */ tmp = build2 (PLUS_EXPR, TREE_TYPE (name2), name2, cst); cst = fold_build2 (PLUS_EXPR, TREE_TYPE (name2), cst, fold_convert (TREE_TYPE (name2), val)); if (comp_code == LT_EXPR || comp_code == GE_EXPR) { new_comp_code = comp_code == LT_EXPR ? LE_EXPR : GT_EXPR; cst = fold_build2 (MINUS_EXPR, TREE_TYPE (name2), cst, build_int_cst (TREE_TYPE (name2), 1)); } if (dump_file) { fprintf (dump_file, "Adding assert for "); print_generic_expr (dump_file, name2, 0); fprintf (dump_file, " from "); print_generic_expr (dump_file, tmp, 0); fprintf (dump_file, "\n"); } register_new_assert_for (name2, tmp, new_comp_code, cst, NULL, e, bsi); } } /* Add asserts for NAME cmp CST and NAME being defined as NAME = NAME2 >> CST2. Extract CST2 from the right shift. */ if (rhs_code == RSHIFT_EXPR) { name2 = gimple_assign_rhs1 (def_stmt); cst2 = gimple_assign_rhs2 (def_stmt); if (TREE_CODE (name2) == SSA_NAME && tree_fits_uhwi_p (cst2) && INTEGRAL_TYPE_P (TREE_TYPE (name2)) && IN_RANGE (tree_to_uhwi (cst2), 1, prec - 1) && prec == GET_MODE_PRECISION (TYPE_MODE (TREE_TYPE (val))) && live_on_edge (e, name2)) { mask = wi::mask (tree_to_uhwi (cst2), false, prec); val2 = fold_binary (LSHIFT_EXPR, TREE_TYPE (val), val, cst2); } } if (val2 != NULL_TREE && TREE_CODE (val2) == INTEGER_CST && simple_cst_equal (fold_build2 (RSHIFT_EXPR, TREE_TYPE (val), val2, cst2), val)) { enum tree_code new_comp_code = comp_code; tree tmp, new_val; tmp = name2; if (comp_code == EQ_EXPR || comp_code == NE_EXPR) { if (!TYPE_UNSIGNED (TREE_TYPE (val))) { tree type = build_nonstandard_integer_type (prec, 1); tmp = build1 (NOP_EXPR, type, name2); val2 = fold_convert (type, val2); } tmp = fold_build2 (MINUS_EXPR, TREE_TYPE (tmp), tmp, val2); new_val = wide_int_to_tree (TREE_TYPE (tmp), mask); new_comp_code = comp_code == EQ_EXPR ? LE_EXPR : GT_EXPR; } else if (comp_code == LT_EXPR || comp_code == GE_EXPR) { wide_int minval = wi::min_value (prec, TYPE_SIGN (TREE_TYPE (val))); new_val = val2; if (minval == new_val) new_val = NULL_TREE; } else { wide_int maxval = wi::max_value (prec, TYPE_SIGN (TREE_TYPE (val))); mask |= val2; if (mask == maxval) new_val = NULL_TREE; else new_val = wide_int_to_tree (TREE_TYPE (val2), mask); } if (new_val) { if (dump_file) { fprintf (dump_file, "Adding assert for "); print_generic_expr (dump_file, name2, 0); fprintf (dump_file, " from "); print_generic_expr (dump_file, tmp, 0); fprintf (dump_file, "\n"); } register_new_assert_for (name2, tmp, new_comp_code, new_val, NULL, e, bsi); } } /* Add asserts for NAME cmp CST and NAME being defined as NAME = NAME2 & CST2. Extract CST2 from the and. Also handle NAME = (unsigned) NAME2; casts where NAME's type is unsigned and has smaller precision than NAME2's type as if it was NAME = NAME2 & MASK. */ names[0] = NULL_TREE; names[1] = NULL_TREE; cst2 = NULL_TREE; if (rhs_code == BIT_AND_EXPR || (CONVERT_EXPR_CODE_P (rhs_code) && INTEGRAL_TYPE_P (TREE_TYPE (val)) && TYPE_UNSIGNED (TREE_TYPE (val)) && TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt))) > prec)) { name2 = gimple_assign_rhs1 (def_stmt); if (rhs_code == BIT_AND_EXPR) cst2 = gimple_assign_rhs2 (def_stmt); else { cst2 = TYPE_MAX_VALUE (TREE_TYPE (val)); nprec = TYPE_PRECISION (TREE_TYPE (name2)); } if (TREE_CODE (name2) == SSA_NAME && INTEGRAL_TYPE_P (TREE_TYPE (name2)) && TREE_CODE (cst2) == INTEGER_CST && !integer_zerop (cst2) && (nprec > 1 || TYPE_UNSIGNED (TREE_TYPE (val)))) { gimple *def_stmt2 = SSA_NAME_DEF_STMT (name2); if (gimple_assign_cast_p (def_stmt2)) { names[1] = gimple_assign_rhs1 (def_stmt2); if (!CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt2)) || !INTEGRAL_TYPE_P (TREE_TYPE (names[1])) || (TYPE_PRECISION (TREE_TYPE (name2)) != TYPE_PRECISION (TREE_TYPE (names[1]))) || !live_on_edge (e, names[1])) names[1] = NULL_TREE; } if (live_on_edge (e, name2)) names[0] = name2; } } if (names[0] || names[1]) { wide_int minv, maxv, valv, cst2v; wide_int tem, sgnbit; bool valid_p = false, valn, cst2n; enum tree_code ccode = comp_code; valv = wide_int::from (val, nprec, UNSIGNED); cst2v = wide_int::from (cst2, nprec, UNSIGNED); valn = wi::neg_p (valv, TYPE_SIGN (TREE_TYPE (val))); cst2n = wi::neg_p (cst2v, TYPE_SIGN (TREE_TYPE (val))); /* If CST2 doesn't have most significant bit set, but VAL is negative, we have comparison like if ((x & 0x123) > -4) (always true). Just give up. */ if (!cst2n && valn) ccode = ERROR_MARK; if (cst2n) sgnbit = wi::set_bit_in_zero (nprec - 1, nprec); else sgnbit = wi::zero (nprec); minv = valv & cst2v; switch (ccode) { case EQ_EXPR: /* Minimum unsigned value for equality is VAL & CST2 (should be equal to VAL, otherwise we probably should have folded the comparison into false) and maximum unsigned value is VAL | ~CST2. */ maxv = valv | ~cst2v; valid_p = true; break; case NE_EXPR: tem = valv | ~cst2v; /* If VAL is 0, handle (X & CST2) != 0 as (X & CST2) > 0U. */ if (valv == 0) { cst2n = false; sgnbit = wi::zero (nprec); goto gt_expr; } /* If (VAL | ~CST2) is all ones, handle it as (X & CST2) < VAL. */ if (tem == -1) { cst2n = false; valn = false; sgnbit = wi::zero (nprec); goto lt_expr; } if (!cst2n && wi::neg_p (cst2v)) sgnbit = wi::set_bit_in_zero (nprec - 1, nprec); if (sgnbit != 0) { if (valv == sgnbit) { cst2n = true; valn = true; goto gt_expr; } if (tem == wi::mask (nprec - 1, false, nprec)) { cst2n = true; goto lt_expr; } if (!cst2n) sgnbit = wi::zero (nprec); } break; case GE_EXPR: /* Minimum unsigned value for >= if (VAL & CST2) == VAL is VAL and maximum unsigned value is ~0. For signed comparison, if CST2 doesn't have most significant bit set, handle it similarly. If CST2 has MSB set, the minimum is the same, and maximum is ~0U/2. */ if (minv != valv) { /* If (VAL & CST2) != VAL, X & CST2 can't be equal to VAL. */ minv = masked_increment (valv, cst2v, sgnbit, nprec); if (minv == valv) break; } maxv = wi::mask (nprec - (cst2n ? 1 : 0), false, nprec); valid_p = true; break; case GT_EXPR: gt_expr: /* Find out smallest MINV where MINV > VAL && (MINV & CST2) == MINV, if any. If VAL is signed and CST2 has MSB set, compute it biased by 1 << (nprec - 1). */ minv = masked_increment (valv, cst2v, sgnbit, nprec); if (minv == valv) break; maxv = wi::mask (nprec - (cst2n ? 1 : 0), false, nprec); valid_p = true; break; case LE_EXPR: /* Minimum unsigned value for <= is 0 and maximum unsigned value is VAL | ~CST2 if (VAL & CST2) == VAL. Otherwise, find smallest VAL2 where VAL2 > VAL && (VAL2 & CST2) == VAL2 and use (VAL2 - 1) | ~CST2 as maximum. For signed comparison, if CST2 doesn't have most significant bit set, handle it similarly. If CST2 has MSB set, the maximum is the same and minimum is INT_MIN. */ if (minv == valv) maxv = valv; else { maxv = masked_increment (valv, cst2v, sgnbit, nprec); if (maxv == valv) break; maxv -= 1; } maxv |= ~cst2v; minv = sgnbit; valid_p = true; break; case LT_EXPR: lt_expr: /* Minimum unsigned value for < is 0 and maximum unsigned value is (VAL-1) | ~CST2 if (VAL & CST2) == VAL. Otherwise, find smallest VAL2 where VAL2 > VAL && (VAL2 & CST2) == VAL2 and use (VAL2 - 1) | ~CST2 as maximum. For signed comparison, if CST2 doesn't have most significant bit set, handle it similarly. If CST2 has MSB set, the maximum is the same and minimum is INT_MIN. */ if (minv == valv) { if (valv == sgnbit) break; maxv = valv; } else { maxv = masked_increment (valv, cst2v, sgnbit, nprec); if (maxv == valv) break; } maxv -= 1; maxv |= ~cst2v; minv = sgnbit; valid_p = true; break; default: break; } if (valid_p && (maxv - minv) != -1) { tree tmp, new_val, type; int i; for (i = 0; i < 2; i++) if (names[i]) { wide_int maxv2 = maxv; tmp = names[i]; type = TREE_TYPE (names[i]); if (!TYPE_UNSIGNED (type)) { type = build_nonstandard_integer_type (nprec, 1); tmp = build1 (NOP_EXPR, type, names[i]); } if (minv != 0) { tmp = build2 (PLUS_EXPR, type, tmp, wide_int_to_tree (type, -minv)); maxv2 = maxv - minv; } new_val = wide_int_to_tree (type, maxv2); if (dump_file) { fprintf (dump_file, "Adding assert for "); print_generic_expr (dump_file, names[i], 0); fprintf (dump_file, " from "); print_generic_expr (dump_file, tmp, 0); fprintf (dump_file, "\n"); } register_new_assert_for (names[i], tmp, LE_EXPR, new_val, NULL, e, bsi); } } } } } /* OP is an operand of a truth value expression which is known to have a particular value. Register any asserts for OP and for any operands in OP's defining statement. If CODE is EQ_EXPR, then we want to register OP is zero (false), if CODE is NE_EXPR, then we want to register OP is nonzero (true). */ static void register_edge_assert_for_1 (tree op, enum tree_code code, edge e, gimple_stmt_iterator bsi) { gimple *op_def; tree val; enum tree_code rhs_code; /* We only care about SSA_NAMEs. */ if (TREE_CODE (op) != SSA_NAME) return; /* We know that OP will have a zero or nonzero value. If OP is used more than once go ahead and register an assert for OP. */ if (live_on_edge (e, op)) { val = build_int_cst (TREE_TYPE (op), 0); register_new_assert_for (op, op, code, val, NULL, e, bsi); } /* Now look at how OP is set. If it's set from a comparison, a truth operation or some bit operations, then we may be able to register information about the operands of that assignment. */ op_def = SSA_NAME_DEF_STMT (op); if (gimple_code (op_def) != GIMPLE_ASSIGN) return; rhs_code = gimple_assign_rhs_code (op_def); if (TREE_CODE_CLASS (rhs_code) == tcc_comparison) { bool invert = (code == EQ_EXPR ? true : false); tree op0 = gimple_assign_rhs1 (op_def); tree op1 = gimple_assign_rhs2 (op_def); if (TREE_CODE (op0) == SSA_NAME) register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1, invert); if (TREE_CODE (op1) == SSA_NAME) register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1, invert); } else if ((code == NE_EXPR && gimple_assign_rhs_code (op_def) == BIT_AND_EXPR) || (code == EQ_EXPR && gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR)) { /* Recurse on each operand. */ tree op0 = gimple_assign_rhs1 (op_def); tree op1 = gimple_assign_rhs2 (op_def); if (TREE_CODE (op0) == SSA_NAME && has_single_use (op0)) register_edge_assert_for_1 (op0, code, e, bsi); if (TREE_CODE (op1) == SSA_NAME && has_single_use (op1)) register_edge_assert_for_1 (op1, code, e, bsi); } else if (gimple_assign_rhs_code (op_def) == BIT_NOT_EXPR && TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (op_def))) == 1) { /* Recurse, flipping CODE. */ code = invert_tree_comparison (code, false); register_edge_assert_for_1 (gimple_assign_rhs1 (op_def), code, e, bsi); } else if (gimple_assign_rhs_code (op_def) == SSA_NAME) { /* Recurse through the copy. */ register_edge_assert_for_1 (gimple_assign_rhs1 (op_def), code, e, bsi); } else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def))) { /* Recurse through the type conversion, unless it is a narrowing conversion or conversion from non-integral type. */ tree rhs = gimple_assign_rhs1 (op_def); if (INTEGRAL_TYPE_P (TREE_TYPE (rhs)) && (TYPE_PRECISION (TREE_TYPE (rhs)) <= TYPE_PRECISION (TREE_TYPE (op)))) register_edge_assert_for_1 (rhs, code, e, bsi); } } /* Try to register an edge assertion for SSA name NAME on edge E for the condition COND contributing to the conditional jump pointed to by SI. */ static void register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si, enum tree_code cond_code, tree cond_op0, tree cond_op1) { tree val; enum tree_code comp_code; bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0; /* Do not attempt to infer anything in names that flow through abnormal edges. */ if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name)) return; if (!extract_code_and_val_from_cond_with_ops (name, cond_code, cond_op0, cond_op1, is_else_edge, &comp_code, &val)) return; /* Register ASSERT_EXPRs for name. */ register_edge_assert_for_2 (name, e, si, cond_code, cond_op0, cond_op1, is_else_edge); /* If COND is effectively an equality test of an SSA_NAME against the value zero or one, then we may be able to assert values for SSA_NAMEs which flow into COND. */ /* In the case of NAME == 1 or NAME != 0, for BIT_AND_EXPR defining statement of NAME we can assert both operands of the BIT_AND_EXPR have nonzero value. */ if (((comp_code == EQ_EXPR && integer_onep (val)) || (comp_code == NE_EXPR && integer_zerop (val)))) { gimple *def_stmt = SSA_NAME_DEF_STMT (name); if (is_gimple_assign (def_stmt) && gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR) { tree op0 = gimple_assign_rhs1 (def_stmt); tree op1 = gimple_assign_rhs2 (def_stmt); register_edge_assert_for_1 (op0, NE_EXPR, e, si); register_edge_assert_for_1 (op1, NE_EXPR, e, si); } } /* In the case of NAME == 0 or NAME != 1, for BIT_IOR_EXPR defining statement of NAME we can assert both operands of the BIT_IOR_EXPR have zero value. */ if (((comp_code == EQ_EXPR && integer_zerop (val)) || (comp_code == NE_EXPR && integer_onep (val)))) { gimple *def_stmt = SSA_NAME_DEF_STMT (name); /* For BIT_IOR_EXPR only if NAME == 0 both operands have necessarily zero value, or if type-precision is one. */ if (is_gimple_assign (def_stmt) && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR && (TYPE_PRECISION (TREE_TYPE (name)) == 1 || comp_code == EQ_EXPR))) { tree op0 = gimple_assign_rhs1 (def_stmt); tree op1 = gimple_assign_rhs2 (def_stmt); register_edge_assert_for_1 (op0, EQ_EXPR, e, si); register_edge_assert_for_1 (op1, EQ_EXPR, e, si); } } } /* Determine whether the outgoing edges of BB should receive an ASSERT_EXPR for each of the operands of BB's LAST statement. The last statement of BB must be a COND_EXPR. If any of the sub-graphs rooted at BB have an interesting use of the predicate operands, an assert location node is added to the list of assertions for the corresponding operands. */ static void find_conditional_asserts (basic_block bb, gcond *last) { gimple_stmt_iterator bsi; tree op; edge_iterator ei; edge e; ssa_op_iter iter; bsi = gsi_for_stmt (last); /* Look for uses of the operands in each of the sub-graphs rooted at BB. We need to check each of the outgoing edges separately, so that we know what kind of ASSERT_EXPR to insert. */ FOR_EACH_EDGE (e, ei, bb->succs) { if (e->dest == bb) continue; /* Register the necessary assertions for each operand in the conditional predicate. */ FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE) register_edge_assert_for (op, e, bsi, gimple_cond_code (last), gimple_cond_lhs (last), gimple_cond_rhs (last)); } } struct case_info { tree expr; basic_block bb; }; /* Compare two case labels sorting first by the destination bb index and then by the case value. */ static int compare_case_labels (const void *p1, const void *p2) { const struct case_info *ci1 = (const struct case_info *) p1; const struct case_info *ci2 = (const struct case_info *) p2; int idx1 = ci1->bb->index; int idx2 = ci2->bb->index; if (idx1 < idx2) return -1; else if (idx1 == idx2) { /* Make sure the default label is first in a group. */ if (!CASE_LOW (ci1->expr)) return -1; else if (!CASE_LOW (ci2->expr)) return 1; else return tree_int_cst_compare (CASE_LOW (ci1->expr), CASE_LOW (ci2->expr)); } else return 1; } /* Determine whether the outgoing edges of BB should receive an ASSERT_EXPR for each of the operands of BB's LAST statement. The last statement of BB must be a SWITCH_EXPR. If any of the sub-graphs rooted at BB have an interesting use of the predicate operands, an assert location node is added to the list of assertions for the corresponding operands. */ static void find_switch_asserts (basic_block bb, gswitch *last) { gimple_stmt_iterator bsi; tree op; edge e; struct case_info *ci; size_t n = gimple_switch_num_labels (last); #if GCC_VERSION >= 4000 unsigned int idx; #else /* Work around GCC 3.4 bug (PR 37086). */ volatile unsigned int idx; #endif bsi = gsi_for_stmt (last); op = gimple_switch_index (last); if (TREE_CODE (op) != SSA_NAME) return; /* Build a vector of case labels sorted by destination label. */ ci = XNEWVEC (struct case_info, n); for (idx = 0; idx < n; ++idx) { ci[idx].expr = gimple_switch_label (last, idx); ci[idx].bb = label_to_block (CASE_LABEL (ci[idx].expr)); } edge default_edge = find_edge (bb, ci[0].bb); qsort (ci, n, sizeof (struct case_info), compare_case_labels); for (idx = 0; idx < n; ++idx) { tree min, max; tree cl = ci[idx].expr; basic_block cbb = ci[idx].bb; min = CASE_LOW (cl); max = CASE_HIGH (cl); /* If there are multiple case labels with the same destination we need to combine them to a single value range for the edge. */ if (idx + 1 < n && cbb == ci[idx + 1].bb) { /* Skip labels until the last of the group. */ do { ++idx; } while (idx < n && cbb == ci[idx].bb); --idx; /* Pick up the maximum of the case label range. */ if (CASE_HIGH (ci[idx].expr)) max = CASE_HIGH (ci[idx].expr); else max = CASE_LOW (ci[idx].expr); } /* Can't extract a useful assertion out of a range that includes the default label. */ if (min == NULL_TREE) continue; /* Find the edge to register the assert expr on. */ e = find_edge (bb, cbb); /* Register the necessary assertions for the operand in the SWITCH_EXPR. */ register_edge_assert_for (op, e, bsi, max ? GE_EXPR : EQ_EXPR, op, fold_convert (TREE_TYPE (op), min)); if (max) register_edge_assert_for (op, e, bsi, LE_EXPR, op, fold_convert (TREE_TYPE (op), max)); } XDELETEVEC (ci); if (!live_on_edge (default_edge, op)) return; /* Now register along the default label assertions that correspond to the anti-range of each label. */ int insertion_limit = PARAM_VALUE (PARAM_MAX_VRP_SWITCH_ASSERTIONS); for (idx = 1; idx < n; idx++) { tree min, max; tree cl = gimple_switch_label (last, idx); min = CASE_LOW (cl); max = CASE_HIGH (cl); /* Combine contiguous case ranges to reduce the number of assertions to insert. */ for (idx = idx + 1; idx < n; idx++) { tree next_min, next_max; tree next_cl = gimple_switch_label (last, idx); next_min = CASE_LOW (next_cl); next_max = CASE_HIGH (next_cl); wide_int difference = wi::sub (next_min, max ? max : min); if (wi::eq_p (difference, 1)) max = next_max ? next_max : next_min; else break; } idx--; if (max == NULL_TREE) { /* Register the assertion OP != MIN. */ min = fold_convert (TREE_TYPE (op), min); register_edge_assert_for (op, default_edge, bsi, NE_EXPR, op, min); } else { /* Register the assertion (unsigned)OP - MIN > (MAX - MIN), which will give OP the anti-range ~[MIN,MAX]. */ tree uop = fold_convert (unsigned_type_for (TREE_TYPE (op)), op); min = fold_convert (TREE_TYPE (uop), min); max = fold_convert (TREE_TYPE (uop), max); tree lhs = fold_build2 (MINUS_EXPR, TREE_TYPE (uop), uop, min); tree rhs = int_const_binop (MINUS_EXPR, max, min); register_new_assert_for (op, lhs, GT_EXPR, rhs, NULL, default_edge, bsi); } if (--insertion_limit == 0) break; } } /* Traverse all the statements in block BB looking for statements that may generate useful assertions for the SSA names in their operand. If a statement produces a useful assertion A for name N_i, then the list of assertions already generated for N_i is scanned to determine if A is actually needed. If N_i already had the assertion A at a location dominating the current location, then nothing needs to be done. Otherwise, the new location for A is recorded instead. 1- For every statement S in BB, all the variables used by S are added to bitmap FOUND_IN_SUBGRAPH. 2- If statement S uses an operand N in a way that exposes a known value range for N, then if N was not already generated by an ASSERT_EXPR, create a new assert location for N. For instance, if N is a pointer and the statement dereferences it, we can assume that N is not NULL. 3- COND_EXPRs are a special case of #2. We can derive range information from the predicate but need to insert different ASSERT_EXPRs for each of the sub-graphs rooted at the conditional block. If the last statement of BB is a conditional expression of the form 'X op Y', then a) Remove X and Y from the set FOUND_IN_SUBGRAPH. b) If the conditional is the only entry point to the sub-graph corresponding to the THEN_CLAUSE, recurse into it. On return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then an ASSERT_EXPR is added for the corresponding variable. c) Repeat step (b) on the ELSE_CLAUSE. d) Mark X and Y in FOUND_IN_SUBGRAPH. For instance, if (a == 9) b = a; else b = c + 1; In this case, an assertion on the THEN clause is useful to determine that 'a' is always 9 on that edge. However, an assertion on the ELSE clause would be unnecessary. 4- If BB does not end in a conditional expression, then we recurse into BB's dominator children. At the end of the recursive traversal, every SSA name will have a list of locations where ASSERT_EXPRs should be added. When a new location for name N is found, it is registered by calling register_new_assert_for. That function keeps track of all the registered assertions to prevent adding unnecessary assertions. For instance, if a pointer P_4 is dereferenced more than once in a dominator tree, only the location dominating all the dereference of P_4 will receive an ASSERT_EXPR. */ static void find_assert_locations_1 (basic_block bb, sbitmap live) { gimple *last; last = last_stmt (bb); /* If BB's last statement is a conditional statement involving integer operands, determine if we need to add ASSERT_EXPRs. */ if (last && gimple_code (last) == GIMPLE_COND && !fp_predicate (last) && !ZERO_SSA_OPERANDS (last, SSA_OP_USE)) find_conditional_asserts (bb, as_a <gcond *> (last)); /* If BB's last statement is a switch statement involving integer operands, determine if we need to add ASSERT_EXPRs. */ if (last && gimple_code (last) == GIMPLE_SWITCH && !ZERO_SSA_OPERANDS (last, SSA_OP_USE)) find_switch_asserts (bb, as_a <gswitch *> (last)); /* Traverse all the statements in BB marking used names and looking for statements that may infer assertions for their used operands. */ for (gimple_stmt_iterator si = gsi_last_bb (bb); !gsi_end_p (si); gsi_prev (&si)) { gimple *stmt; tree op; ssa_op_iter i; stmt = gsi_stmt (si); if (is_gimple_debug (stmt)) continue; /* See if we can derive an assertion for any of STMT's operands. */ FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE) { tree value; enum tree_code comp_code; /* If op is not live beyond this stmt, do not bother to insert asserts for it. */ if (!bitmap_bit_p (live, SSA_NAME_VERSION (op))) continue; /* If OP is used in such a way that we can infer a value range for it, and we don't find a previous assertion for it, create a new assertion location node for OP. */ if (infer_value_range (stmt, op, &comp_code, &value)) { /* If we are able to infer a nonzero value range for OP, then walk backwards through the use-def chain to see if OP was set via a typecast. If so, then we can also infer a nonzero value range for the operand of the NOP_EXPR. */ if (comp_code == NE_EXPR && integer_zerop (value)) { tree t = op; gimple *def_stmt = SSA_NAME_DEF_STMT (t); while (is_gimple_assign (def_stmt) && CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)) && TREE_CODE (gimple_assign_rhs1 (def_stmt)) == SSA_NAME && POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))) { t = gimple_assign_rhs1 (def_stmt); def_stmt = SSA_NAME_DEF_STMT (t); /* Note we want to register the assert for the operand of the NOP_EXPR after SI, not after the conversion. */ if (bitmap_bit_p (live, SSA_NAME_VERSION (t))) register_new_assert_for (t, t, comp_code, value, bb, NULL, si); } } register_new_assert_for (op, op, comp_code, value, bb, NULL, si); } } /* Update live. */ FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE) bitmap_set_bit (live, SSA_NAME_VERSION (op)); FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_DEF) bitmap_clear_bit (live, SSA_NAME_VERSION (op)); } /* Traverse all PHI nodes in BB, updating live. */ for (gphi_iterator si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si)) { use_operand_p arg_p; ssa_op_iter i; gphi *phi = si.phi (); tree res = gimple_phi_result (phi); if (virtual_operand_p (res)) continue; FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE) { tree arg = USE_FROM_PTR (arg_p); if (TREE_CODE (arg) == SSA_NAME) bitmap_set_bit (live, SSA_NAME_VERSION (arg)); } bitmap_clear_bit (live, SSA_NAME_VERSION (res)); } } /* Do an RPO walk over the function computing SSA name liveness on-the-fly and deciding on assert expressions to insert. */ static void find_assert_locations (void) { int *rpo = XNEWVEC (int, last_basic_block_for_fn (cfun)); int *bb_rpo = XNEWVEC (int, last_basic_block_for_fn (cfun)); int *last_rpo = XCNEWVEC (int, last_basic_block_for_fn (cfun)); int rpo_cnt, i; live = XCNEWVEC (sbitmap, last_basic_block_for_fn (cfun)); rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false); for (i = 0; i < rpo_cnt; ++i) bb_rpo[rpo[i]] = i; /* Pre-seed loop latch liveness from loop header PHI nodes. Due to the order we compute liveness and insert asserts we otherwise fail to insert asserts into the loop latch. */ loop_p loop; FOR_EACH_LOOP (loop, 0) { i = loop->latch->index; unsigned int j = single_succ_edge (loop->latch)->dest_idx; for (gphi_iterator gsi = gsi_start_phis (loop->header); !gsi_end_p (gsi); gsi_next (&gsi)) { gphi *phi = gsi.phi (); if (virtual_operand_p (gimple_phi_result (phi))) continue; tree arg = gimple_phi_arg_def (phi, j); if (TREE_CODE (arg) == SSA_NAME) { if (live[i] == NULL) { live[i] = sbitmap_alloc (num_ssa_names); bitmap_clear (live[i]); } bitmap_set_bit (live[i], SSA_NAME_VERSION (arg)); } } } for (i = rpo_cnt - 1; i >= 0; --i) { basic_block bb = BASIC_BLOCK_FOR_FN (cfun, rpo[i]); edge e; edge_iterator ei; if (!live[rpo[i]]) { live[rpo[i]] = sbitmap_alloc (num_ssa_names); bitmap_clear (live[rpo[i]]); } /* Process BB and update the live information with uses in this block. */ find_assert_locations_1 (bb, live[rpo[i]]); /* Merge liveness into the predecessor blocks and free it. */ if (!bitmap_empty_p (live[rpo[i]])) { int pred_rpo = i; FOR_EACH_EDGE (e, ei, bb->preds) { int pred = e->src->index; if ((e->flags & EDGE_DFS_BACK) || pred == ENTRY_BLOCK) continue; if (!live[pred]) { live[pred] = sbitmap_alloc (num_ssa_names); bitmap_clear (live[pred]); } bitmap_ior (live[pred], live[pred], live[rpo[i]]); if (bb_rpo[pred] < pred_rpo) pred_rpo = bb_rpo[pred]; } /* Record the RPO number of the last visited block that needs live information from this block. */ last_rpo[rpo[i]] = pred_rpo; } else { sbitmap_free (live[rpo[i]]); live[rpo[i]] = NULL; } /* We can free all successors live bitmaps if all their predecessors have been visited already. */ FOR_EACH_EDGE (e, ei, bb->succs) if (last_rpo[e->dest->index] == i && live[e->dest->index]) { sbitmap_free (live[e->dest->index]); live[e->dest->index] = NULL; } } XDELETEVEC (rpo); XDELETEVEC (bb_rpo); XDELETEVEC (last_rpo); for (i = 0; i < last_basic_block_for_fn (cfun); ++i) if (live[i]) sbitmap_free (live[i]); XDELETEVEC (live); } /* Create an ASSERT_EXPR for NAME and insert it in the location indicated by LOC. Return true if we made any edge insertions. */ static bool process_assert_insertions_for (tree name, assert_locus *loc) { /* Build the comparison expression NAME_i COMP_CODE VAL. */ gimple *stmt; tree cond; gimple *assert_stmt; edge_iterator ei; edge e; /* If we have X <=> X do not insert an assert expr for that. */ if (loc->expr == loc->val) return false; cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val); assert_stmt = build_assert_expr_for (cond, name); if (loc->e) { /* We have been asked to insert the assertion on an edge. This is used only by COND_EXPR and SWITCH_EXPR assertions. */ gcc_checking_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND || (gimple_code (gsi_stmt (loc->si)) == GIMPLE_SWITCH)); gsi_insert_on_edge (loc->e, assert_stmt); return true; } /* Otherwise, we can insert right after LOC->SI iff the statement must not be the last statement in the block. */ stmt = gsi_stmt (loc->si); if (!stmt_ends_bb_p (stmt)) { gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT); return false; } /* If STMT must be the last statement in BB, we can only insert new assertions on the non-abnormal edge out of BB. Note that since STMT is not control flow, there may only be one non-abnormal/eh edge out of BB. */ FOR_EACH_EDGE (e, ei, loc->bb->succs) if (!(e->flags & (EDGE_ABNORMAL|EDGE_EH))) { gsi_insert_on_edge (e, assert_stmt); return true; } gcc_unreachable (); } /* Process all the insertions registered for every name N_i registered in NEED_ASSERT_FOR. The list of assertions to be inserted are found in ASSERTS_FOR[i]. */ static void process_assert_insertions (void) { unsigned i; bitmap_iterator bi; bool update_edges_p = false; int num_asserts = 0; if (dump_file && (dump_flags & TDF_DETAILS)) dump_all_asserts (dump_file); EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi) { assert_locus *loc = asserts_for[i]; gcc_assert (loc); while (loc) { assert_locus *next = loc->next; update_edges_p |= process_assert_insertions_for (ssa_name (i), loc); free (loc); loc = next; num_asserts++; } } if (update_edges_p) gsi_commit_edge_inserts (); statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted", num_asserts); } /* Traverse the flowgraph looking for conditional jumps to insert range expressions. These range expressions are meant to provide information to optimizations that need to reason in terms of value ranges. They will not be expanded into RTL. For instance, given: x = ... y = ... if (x < y) y = x - 2; else x = y + 3; this pass will transform the code into: x = ... y = ... if (x < y) { x = ASSERT_EXPR <x, x < y> y = x - 2 } else { y = ASSERT_EXPR <y, x >= y> x = y + 3 } The idea is that once copy and constant propagation have run, other optimizations will be able to determine what ranges of values can 'x' take in different paths of the code, simply by checking the reaching definition of 'x'. */ static void insert_range_assertions (void) { need_assert_for = BITMAP_ALLOC (NULL); asserts_for = XCNEWVEC (assert_locus *, num_ssa_names); calculate_dominance_info (CDI_DOMINATORS); find_assert_locations (); if (!bitmap_empty_p (need_assert_for)) { process_assert_insertions (); update_ssa (TODO_update_ssa_no_phi); } if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n"); dump_function_to_file (current_function_decl, dump_file, dump_flags); } free (asserts_for); BITMAP_FREE (need_assert_for); } /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays and "struct" hacks. If VRP can determine that the array subscript is a constant, check if it is outside valid range. If the array subscript is a RANGE, warn if it is non-overlapping with valid range. IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */ static void check_array_ref (location_t location, tree ref, bool ignore_off_by_one) { value_range *vr = NULL; tree low_sub, up_sub; tree low_bound, up_bound, up_bound_p1; if (TREE_NO_WARNING (ref)) return; low_sub = up_sub = TREE_OPERAND (ref, 1); up_bound = array_ref_up_bound (ref); /* Can not check flexible arrays. */ if (!up_bound || TREE_CODE (up_bound) != INTEGER_CST) return; /* Accesses to trailing arrays via pointers may access storage beyond the types array bounds. */ if (warn_array_bounds < 2 && array_at_struct_end_p (ref)) return; low_bound = array_ref_low_bound (ref); up_bound_p1 = int_const_binop (PLUS_EXPR, up_bound, build_int_cst (TREE_TYPE (up_bound), 1)); /* Empty array. */ if (tree_int_cst_equal (low_bound, up_bound_p1)) { warning_at (location, OPT_Warray_bounds, "array subscript is above array bounds"); TREE_NO_WARNING (ref) = 1; } if (TREE_CODE (low_sub) == SSA_NAME) { vr = get_value_range (low_sub); if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE) { low_sub = vr->type == VR_RANGE ? vr->max : vr->min; up_sub = vr->type == VR_RANGE ? vr->min : vr->max; } } if (vr && vr->type == VR_ANTI_RANGE) { if (TREE_CODE (up_sub) == INTEGER_CST && (ignore_off_by_one ? tree_int_cst_lt (up_bound, up_sub) : tree_int_cst_le (up_bound, up_sub)) && TREE_CODE (low_sub) == INTEGER_CST && tree_int_cst_le (low_sub, low_bound)) { warning_at (location, OPT_Warray_bounds, "array subscript is outside array bounds"); TREE_NO_WARNING (ref) = 1; } } else if (TREE_CODE (up_sub) == INTEGER_CST && (ignore_off_by_one ? !tree_int_cst_le (up_sub, up_bound_p1) : !tree_int_cst_le (up_sub, up_bound))) { if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "Array bound warning for "); dump_generic_expr (MSG_NOTE, TDF_SLIM, ref); fprintf (dump_file, "\n"); } warning_at (location, OPT_Warray_bounds, "array subscript is above array bounds"); TREE_NO_WARNING (ref) = 1; } else if (TREE_CODE (low_sub) == INTEGER_CST && tree_int_cst_lt (low_sub, low_bound)) { if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "Array bound warning for "); dump_generic_expr (MSG_NOTE, TDF_SLIM, ref); fprintf (dump_file, "\n"); } warning_at (location, OPT_Warray_bounds, "array subscript is below array bounds"); TREE_NO_WARNING (ref) = 1; } } /* Searches if the expr T, located at LOCATION computes address of an ARRAY_REF, and call check_array_ref on it. */ static void search_for_addr_array (tree t, location_t location) { /* Check each ARRAY_REFs in the reference chain. */ do { if (TREE_CODE (t) == ARRAY_REF) check_array_ref (location, t, true /*ignore_off_by_one*/); t = TREE_OPERAND (t, 0); } while (handled_component_p (t)); if (TREE_CODE (t) == MEM_REF && TREE_CODE (TREE_OPERAND (t, 0)) == ADDR_EXPR && !TREE_NO_WARNING (t)) { tree tem = TREE_OPERAND (TREE_OPERAND (t, 0), 0); tree low_bound, up_bound, el_sz; offset_int idx; if (TREE_CODE (TREE_TYPE (tem)) != ARRAY_TYPE || TREE_CODE (TREE_TYPE (TREE_TYPE (tem))) == ARRAY_TYPE || !TYPE_DOMAIN (TREE_TYPE (tem))) return; low_bound = TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem))); up_bound = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem))); el_sz = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem))); if (!low_bound || TREE_CODE (low_bound) != INTEGER_CST || !up_bound || TREE_CODE (up_bound) != INTEGER_CST || !el_sz || TREE_CODE (el_sz) != INTEGER_CST) return; idx = mem_ref_offset (t); idx = wi::sdiv_trunc (idx, wi::to_offset (el_sz)); if (idx < 0) { if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "Array bound warning for "); dump_generic_expr (MSG_NOTE, TDF_SLIM, t); fprintf (dump_file, "\n"); } warning_at (location, OPT_Warray_bounds, "array subscript is below array bounds"); TREE_NO_WARNING (t) = 1; } else if (idx > (wi::to_offset (up_bound) - wi::to_offset (low_bound) + 1)) { if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "Array bound warning for "); dump_generic_expr (MSG_NOTE, TDF_SLIM, t); fprintf (dump_file, "\n"); } warning_at (location, OPT_Warray_bounds, "array subscript is above array bounds"); TREE_NO_WARNING (t) = 1; } } } /* walk_tree() callback that checks if *TP is an ARRAY_REF inside an ADDR_EXPR (in which an array subscript one outside the valid range is allowed). Call check_array_ref for each ARRAY_REF found. The location is passed in DATA. */ static tree check_array_bounds (tree *tp, int *walk_subtree, void *data) { tree t = *tp; struct walk_stmt_info *wi = (struct walk_stmt_info *) data; location_t location; if (EXPR_HAS_LOCATION (t)) location = EXPR_LOCATION (t); else { location_t *locp = (location_t *) wi->info; location = *locp; } *walk_subtree = TRUE; if (TREE_CODE (t) == ARRAY_REF) check_array_ref (location, t, false /*ignore_off_by_one*/); else if (TREE_CODE (t) == ADDR_EXPR) { search_for_addr_array (t, location); *walk_subtree = FALSE; } return NULL_TREE; } /* Walk over all statements of all reachable BBs and call check_array_bounds on them. */ static void check_all_array_refs (void) { basic_block bb; gimple_stmt_iterator si; FOR_EACH_BB_FN (bb, cfun) { edge_iterator ei; edge e; bool executable = false; /* Skip blocks that were found to be unreachable. */ FOR_EACH_EDGE (e, ei, bb->preds) executable |= !!(e->flags & EDGE_EXECUTABLE); if (!executable) continue; for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si)) { gimple *stmt = gsi_stmt (si); struct walk_stmt_info wi; if (!gimple_has_location (stmt) || is_gimple_debug (stmt)) continue; memset (&wi, 0, sizeof (wi)); location_t loc = gimple_location (stmt); wi.info = &loc; walk_gimple_op (gsi_stmt (si), check_array_bounds, &wi); } } } /* Return true if all imm uses of VAR are either in STMT, or feed (optionally through a chain of single imm uses) GIMPLE_COND in basic block COND_BB. */ static bool all_imm_uses_in_stmt_or_feed_cond (tree var, gimple *stmt, basic_block cond_bb) { use_operand_p use_p, use2_p; imm_use_iterator iter; FOR_EACH_IMM_USE_FAST (use_p, iter, var) if (USE_STMT (use_p) != stmt) { gimple *use_stmt = USE_STMT (use_p), *use_stmt2; if (is_gimple_debug (use_stmt)) continue; while (is_gimple_assign (use_stmt) && TREE_CODE (gimple_assign_lhs (use_stmt)) == SSA_NAME && single_imm_use (gimple_assign_lhs (use_stmt), &use2_p, &use_stmt2)) use_stmt = use_stmt2; if (gimple_code (use_stmt) != GIMPLE_COND || gimple_bb (use_stmt) != cond_bb) return false; } return true; } /* Handle _4 = x_3 & 31; if (_4 != 0) goto <bb 6>; else goto <bb 7>; <bb 6>: __builtin_unreachable (); <bb 7>: x_5 = ASSERT_EXPR <x_3, ...>; If x_3 has no other immediate uses (checked by caller), var is the x_3 var from ASSERT_EXPR, we can clear low 5 bits from the non-zero bitmask. */ static void maybe_set_nonzero_bits (basic_block bb, tree var) { edge e = single_pred_edge (bb); basic_block cond_bb = e->src; gimple *stmt = last_stmt (cond_bb); tree cst; if (stmt == NULL || gimple_code (stmt) != GIMPLE_COND || gimple_cond_code (stmt) != ((e->flags & EDGE_TRUE_VALUE) ? EQ_EXPR : NE_EXPR) || TREE_CODE (gimple_cond_lhs (stmt)) != SSA_NAME || !integer_zerop (gimple_cond_rhs (stmt))) return; stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (stmt)); if (!is_gimple_assign (stmt) || gimple_assign_rhs_code (stmt) != BIT_AND_EXPR || TREE_CODE (gimple_assign_rhs2 (stmt)) != INTEGER_CST) return; if (gimple_assign_rhs1 (stmt) != var) { gimple *stmt2; if (TREE_CODE (gimple_assign_rhs1 (stmt)) != SSA_NAME) return; stmt2 = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt)); if (!gimple_assign_cast_p (stmt2) || gimple_assign_rhs1 (stmt2) != var || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt2)) || (TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (stmt))) != TYPE_PRECISION (TREE_TYPE (var)))) return; } cst = gimple_assign_rhs2 (stmt); set_nonzero_bits (var, wi::bit_and_not (get_nonzero_bits (var), cst)); } /* Convert range assertion expressions into the implied copies and copy propagate away the copies. Doing the trivial copy propagation here avoids the need to run the full copy propagation pass after VRP. FIXME, this will eventually lead to copy propagation removing the names that had useful range information attached to them. For instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>, then N_i will have the range [3, +INF]. However, by converting the assertion into the implied copy operation N_i = N_j, we will then copy-propagate N_j into the uses of N_i and lose the range information. We may want to hold on to ASSERT_EXPRs a little while longer as the ranges could be used in things like jump threading. The problem with keeping ASSERT_EXPRs around is that passes after VRP need to handle them appropriately. Another approach would be to make the range information a first class property of the SSA_NAME so that it can be queried from any pass. This is made somewhat more complex by the need for multiple ranges to be associated with one SSA_NAME. */ static void remove_range_assertions (void) { basic_block bb; gimple_stmt_iterator si; /* 1 if looking at ASSERT_EXPRs immediately at the beginning of a basic block preceeded by GIMPLE_COND branching to it and __builtin_trap, -1 if not yet checked, 0 otherwise. */ int is_unreachable; /* Note that the BSI iterator bump happens at the bottom of the loop and no bump is necessary if we're removing the statement referenced by the current BSI. */ FOR_EACH_BB_FN (bb, cfun) for (si = gsi_after_labels (bb), is_unreachable = -1; !gsi_end_p (si);) { gimple *stmt = gsi_stmt (si); if (is_gimple_assign (stmt) && gimple_assign_rhs_code (stmt) == ASSERT_EXPR) { tree lhs = gimple_assign_lhs (stmt); tree rhs = gimple_assign_rhs1 (stmt); tree var; var = ASSERT_EXPR_VAR (rhs); if (TREE_CODE (var) == SSA_NAME && !POINTER_TYPE_P (TREE_TYPE (lhs)) && SSA_NAME_RANGE_INFO (lhs)) { if (is_unreachable == -1) { is_unreachable = 0; if (single_pred_p (bb) && assert_unreachable_fallthru_edge_p (single_pred_edge (bb))) is_unreachable = 1; } /* Handle if (x_7 >= 10 && x_7 < 20) __builtin_unreachable (); x_8 = ASSERT_EXPR <x_7, ...>; if the only uses of x_7 are in the ASSERT_EXPR and in the condition. In that case, we can copy the range info from x_8 computed in this pass also for x_7. */ if (is_unreachable && all_imm_uses_in_stmt_or_feed_cond (var, stmt, single_pred (bb))) { set_range_info (var, SSA_NAME_RANGE_TYPE (lhs), SSA_NAME_RANGE_INFO (lhs)->get_min (), SSA_NAME_RANGE_INFO (lhs)->get_max ()); maybe_set_nonzero_bits (bb, var); } } /* Propagate the RHS into every use of the LHS. */ replace_uses_by (lhs, var); /* And finally, remove the copy, it is not needed. */ gsi_remove (&si, true); release_defs (stmt); } else { if (!is_gimple_debug (gsi_stmt (si))) is_unreachable = 0; gsi_next (&si); } } } /* Return true if STMT is interesting for VRP. */ static bool stmt_interesting_for_vrp (gimple *stmt) { if (gimple_code (stmt) == GIMPLE_PHI) { tree res = gimple_phi_result (stmt); return (!virtual_operand_p (res) && (INTEGRAL_TYPE_P (TREE_TYPE (res)) || POINTER_TYPE_P (TREE_TYPE (res)))); } else if (is_gimple_assign (stmt) || is_gimple_call (stmt)) { tree lhs = gimple_get_lhs (stmt); /* In general, assignments with virtual operands are not useful for deriving ranges, with the obvious exception of calls to builtin functions. */ if (lhs && TREE_CODE (lhs) == SSA_NAME && (INTEGRAL_TYPE_P (TREE_TYPE (lhs)) || POINTER_TYPE_P (TREE_TYPE (lhs))) && (is_gimple_call (stmt) || !gimple_vuse (stmt))) return true; else if (is_gimple_call (stmt) && gimple_call_internal_p (stmt)) switch (gimple_call_internal_fn (stmt)) { case IFN_ADD_OVERFLOW: case IFN_SUB_OVERFLOW: case IFN_MUL_OVERFLOW: /* These internal calls return _Complex integer type, but are interesting to VRP nevertheless. */ if (lhs && TREE_CODE (lhs) == SSA_NAME) return true; break; default: break; } } else if (gimple_code (stmt) == GIMPLE_COND || gimple_code (stmt) == GIMPLE_SWITCH) return true; return false; } /* Initialize VRP lattice. */ static void vrp_initialize_lattice () { values_propagated = false; num_vr_values = num_ssa_names; vr_value = XCNEWVEC (value_range *, num_vr_values); vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names); bitmap_obstack_initialize (&vrp_equiv_obstack); } /* Initialization required by ssa_propagate engine. */ static void vrp_initialize () { basic_block bb; FOR_EACH_BB_FN (bb, cfun) { for (gphi_iterator si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si)) { gphi *phi = si.phi (); if (!stmt_interesting_for_vrp (phi)) { tree lhs = PHI_RESULT (phi); set_value_range_to_varying (get_value_range (lhs)); prop_set_simulate_again (phi, false); } else prop_set_simulate_again (phi, true); } for (gimple_stmt_iterator si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si)) { gimple *stmt = gsi_stmt (si); /* If the statement is a control insn, then we do not want to avoid simulating the statement once. Failure to do so means that those edges will never get added. */ if (stmt_ends_bb_p (stmt)) prop_set_simulate_again (stmt, true); else if (!stmt_interesting_for_vrp (stmt)) { set_defs_to_varying (stmt); prop_set_simulate_again (stmt, false); } else prop_set_simulate_again (stmt, true); } } } /* Return the singleton value-range for NAME or NAME. */ static inline tree vrp_valueize (tree name) { if (TREE_CODE (name) == SSA_NAME) { value_range *vr = get_value_range (name); if (vr->type == VR_RANGE && (TREE_CODE (vr->min) == SSA_NAME || is_gimple_min_invariant (vr->min)) && vrp_operand_equal_p (vr->min, vr->max)) return vr->min; } return name; } /* Return the singleton value-range for NAME if that is a constant but signal to not follow SSA edges. */ static inline tree vrp_valueize_1 (tree name) { if (TREE_CODE (name) == SSA_NAME) { /* If the definition may be simulated again we cannot follow this SSA edge as the SSA propagator does not necessarily re-visit the use. */ gimple *def_stmt = SSA_NAME_DEF_STMT (name); if (!gimple_nop_p (def_stmt) && prop_simulate_again_p (def_stmt)) return NULL_TREE; value_range *vr = get_value_range (name); if (range_int_cst_singleton_p (vr)) return vr->min; } return name; } /* Visit assignment STMT. If it produces an interesting range, record the range in VR and set LHS to OUTPUT_P. */ static void vrp_visit_assignment_or_call (gimple *stmt, tree *output_p, value_range *vr) { tree lhs; enum gimple_code code = gimple_code (stmt); lhs = gimple_get_lhs (stmt); *output_p = NULL_TREE; /* We only keep track of ranges in integral and pointer types. */ if (TREE_CODE (lhs) == SSA_NAME && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs)) /* It is valid to have NULL MIN/MAX values on a type. See build_range_type. */ && TYPE_MIN_VALUE (TREE_TYPE (lhs)) && TYPE_MAX_VALUE (TREE_TYPE (lhs))) || POINTER_TYPE_P (TREE_TYPE (lhs)))) { /* Try folding the statement to a constant first. */ tree tem = gimple_fold_stmt_to_constant_1 (stmt, vrp_valueize, vrp_valueize_1); if (tem && is_gimple_min_invariant (tem)) set_value_range_to_value (vr, tem, NULL); /* Then dispatch to value-range extracting functions. */ else if (code == GIMPLE_CALL) extract_range_basic (vr, stmt); else extract_range_from_assignment (vr, as_a <gassign *> (stmt)); *output_p = lhs; } } /* Helper that gets the value range of the SSA_NAME with version I or a symbolic range containing the SSA_NAME only if the value range is varying or undefined. */ static inline value_range get_vr_for_comparison (int i) { value_range vr = *get_value_range (ssa_name (i)); /* If name N_i does not have a valid range, use N_i as its own range. This allows us to compare against names that may have N_i in their ranges. */ if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED) { vr.type = VR_RANGE; vr.min = ssa_name (i); vr.max = ssa_name (i); } return vr; } /* Compare all the value ranges for names equivalent to VAR with VAL using comparison code COMP. Return the same value returned by compare_range_with_value, including the setting of *STRICT_OVERFLOW_P. */ static tree compare_name_with_value (enum tree_code comp, tree var, tree val, bool *strict_overflow_p, bool use_equiv_p) { bitmap_iterator bi; unsigned i; bitmap e; tree retval, t; int used_strict_overflow; bool sop; value_range equiv_vr; /* Get the set of equivalences for VAR. */ e = get_value_range (var)->equiv; /* Start at -1. Set it to 0 if we do a comparison without relying on overflow, or 1 if all comparisons rely on overflow. */ used_strict_overflow = -1; /* Compare vars' value range with val. */ equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var)); sop = false; retval = compare_range_with_value (comp, &equiv_vr, val, &sop); if (retval) used_strict_overflow = sop ? 1 : 0; /* If the equiv set is empty we have done all work we need to do. */ if (e == NULL) { if (retval && used_strict_overflow > 0) *strict_overflow_p = true; return retval; } EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi) { tree name = ssa_name (i); if (! name) continue; if (! use_equiv_p && ! SSA_NAME_IS_DEFAULT_DEF (name) && prop_simulate_again_p (SSA_NAME_DEF_STMT (name))) continue; equiv_vr = get_vr_for_comparison (i); sop = false; t = compare_range_with_value (comp, &equiv_vr, val, &sop); if (t) { /* If we get different answers from different members of the equivalence set this check must be in a dead code region. Folding it to a trap representation would be correct here. For now just return don't-know. */ if (retval != NULL && t != retval) { retval = NULL_TREE; break; } retval = t; if (!sop) used_strict_overflow = 0; else if (used_strict_overflow < 0) used_strict_overflow = 1; } } if (retval && used_strict_overflow > 0) *strict_overflow_p = true; return retval; } /* Given a comparison code COMP and names N1 and N2, compare all the ranges equivalent to N1 against all the ranges equivalent to N2 to determine the value of N1 COMP N2. Return the same value returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate whether we relied on an overflow infinity in the comparison. */ static tree compare_names (enum tree_code comp, tree n1, tree n2, bool *strict_overflow_p) { tree t, retval; bitmap e1, e2; bitmap_iterator bi1, bi2; unsigned i1, i2; int used_strict_overflow; static bitmap_obstack *s_obstack = NULL; static bitmap s_e1 = NULL, s_e2 = NULL; /* Compare the ranges of every name equivalent to N1 against the ranges of every name equivalent to N2. */ e1 = get_value_range (n1)->equiv; e2 = get_value_range (n2)->equiv; /* Use the fake bitmaps if e1 or e2 are not available. */ if (s_obstack == NULL) { s_obstack = XNEW (bitmap_obstack); bitmap_obstack_initialize (s_obstack); s_e1 = BITMAP_ALLOC (s_obstack); s_e2 = BITMAP_ALLOC (s_obstack); } if (e1 == NULL) e1 = s_e1; if (e2 == NULL) e2 = s_e2; /* Add N1 and N2 to their own set of equivalences to avoid duplicating the body of the loop just to check N1 and N2 ranges. */ bitmap_set_bit (e1, SSA_NAME_VERSION (n1)); bitmap_set_bit (e2, SSA_NAME_VERSION (n2)); /* If the equivalence sets have a common intersection, then the two names can be compared without checking their ranges. */ if (bitmap_intersect_p (e1, e2)) { bitmap_clear_bit (e1, SSA_NAME_VERSION (n1)); bitmap_clear_bit (e2, SSA_NAME_VERSION (n2)); return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR) ? boolean_true_node : boolean_false_node; } /* Start at -1. Set it to 0 if we do a comparison without relying on overflow, or 1 if all comparisons rely on overflow. */ used_strict_overflow = -1; /* Otherwise, compare all the equivalent ranges. First, add N1 and N2 to their own set of equivalences to avoid duplicating the body of the loop just to check N1 and N2 ranges. */ EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1) { if (! ssa_name (i1)) continue; value_range vr1 = get_vr_for_comparison (i1); t = retval = NULL_TREE; EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2) { if (! ssa_name (i2)) continue; bool sop = false; value_range vr2 = get_vr_for_comparison (i2); t = compare_ranges (comp, &vr1, &vr2, &sop); if (t) { /* If we get different answers from different members of the equivalence set this check must be in a dead code region. Folding it to a trap representation would be correct here. For now just return don't-know. */ if (retval != NULL && t != retval) { bitmap_clear_bit (e1, SSA_NAME_VERSION (n1)); bitmap_clear_bit (e2, SSA_NAME_VERSION (n2)); return NULL_TREE; } retval = t; if (!sop) used_strict_overflow = 0; else if (used_strict_overflow < 0) used_strict_overflow = 1; } } if (retval) { bitmap_clear_bit (e1, SSA_NAME_VERSION (n1)); bitmap_clear_bit (e2, SSA_NAME_VERSION (n2)); if (used_strict_overflow > 0) *strict_overflow_p = true; return retval; } } /* None of the equivalent ranges are useful in computing this comparison. */ bitmap_clear_bit (e1, SSA_NAME_VERSION (n1)); bitmap_clear_bit (e2, SSA_NAME_VERSION (n2)); return NULL_TREE; } /* Helper function for vrp_evaluate_conditional_warnv & other optimizers. */ static tree vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code, tree op0, tree op1, bool * strict_overflow_p) { value_range *vr0, *vr1; vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL; vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL; tree res = NULL_TREE; if (vr0 && vr1) res = compare_ranges (code, vr0, vr1, strict_overflow_p); if (!res && vr0) res = compare_range_with_value (code, vr0, op1, strict_overflow_p); if (!res && vr1) res = (compare_range_with_value (swap_tree_comparison (code), vr1, op0, strict_overflow_p)); return res; } /* Helper function for vrp_evaluate_conditional_warnv. */ static tree vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0, tree op1, bool use_equiv_p, bool *strict_overflow_p, bool *only_ranges) { tree ret; if (only_ranges) *only_ranges = true; /* We only deal with integral and pointer types. */ if (!INTEGRAL_TYPE_P (TREE_TYPE (op0)) && !POINTER_TYPE_P (TREE_TYPE (op0))) return NULL_TREE; if ((ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1, strict_overflow_p))) return ret; if (only_ranges) *only_ranges = false; /* Do not use compare_names during propagation, it's quadratic. */ if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME && use_equiv_p) return compare_names (code, op0, op1, strict_overflow_p); else if (TREE_CODE (op0) == SSA_NAME) return compare_name_with_value (code, op0, op1, strict_overflow_p, use_equiv_p); else if (TREE_CODE (op1) == SSA_NAME) return compare_name_with_value (swap_tree_comparison (code), op1, op0, strict_overflow_p, use_equiv_p); return NULL_TREE; } /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range information. Return NULL if the conditional can not be evaluated. The ranges of all the names equivalent with the operands in COND will be used when trying to compute the value. If the result is based on undefined signed overflow, issue a warning if appropriate. */ static tree vrp_evaluate_conditional (tree_code code, tree op0, tree op1, gimple *stmt) { bool sop; tree ret; bool only_ranges; /* Some passes and foldings leak constants with overflow flag set into the IL. Avoid doing wrong things with these and bail out. */ if ((TREE_CODE (op0) == INTEGER_CST && TREE_OVERFLOW (op0)) || (TREE_CODE (op1) == INTEGER_CST && TREE_OVERFLOW (op1))) return NULL_TREE; sop = false; ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop, &only_ranges); if (ret && sop) { enum warn_strict_overflow_code wc; const char* warnmsg; if (is_gimple_min_invariant (ret)) { wc = WARN_STRICT_OVERFLOW_CONDITIONAL; warnmsg = G_("assuming signed overflow does not occur when " "simplifying conditional to constant"); } else { wc = WARN_STRICT_OVERFLOW_COMPARISON; warnmsg = G_("assuming signed overflow does not occur when " "simplifying conditional"); } if (issue_strict_overflow_warning (wc)) { location_t location; if (!gimple_has_location (stmt)) location = input_location; else location = gimple_location (stmt); warning_at (location, OPT_Wstrict_overflow, "%s", warnmsg); } } if (warn_type_limits && ret && only_ranges && TREE_CODE_CLASS (code) == tcc_comparison && TREE_CODE (op0) == SSA_NAME) { /* If the comparison is being folded and the operand on the LHS is being compared against a constant value that is outside of the natural range of OP0's type, then the predicate will always fold regardless of the value of OP0. If -Wtype-limits was specified, emit a warning. */ tree type = TREE_TYPE (op0); value_range *vr0 = get_value_range (op0); if (vr0->type == VR_RANGE && INTEGRAL_TYPE_P (type) && vrp_val_is_min (vr0->min) && vrp_val_is_max (vr0->max) && is_gimple_min_invariant (op1)) { location_t location; if (!gimple_has_location (stmt)) location = input_location; else location = gimple_location (stmt); warning_at (location, OPT_Wtype_limits, integer_zerop (ret) ? G_("comparison always false " "due to limited range of data type") : G_("comparison always true " "due to limited range of data type")); } } return ret; } /* Visit conditional statement STMT. If we can determine which edge will be taken out of STMT's basic block, record it in *TAKEN_EDGE_P. Otherwise, set *TAKEN_EDGE_P to NULL. */ static void vrp_visit_cond_stmt (gcond *stmt, edge *taken_edge_p) { tree val; bool sop; *taken_edge_p = NULL; if (dump_file && (dump_flags & TDF_DETAILS)) { tree use; ssa_op_iter i; fprintf (dump_file, "\nVisiting conditional with predicate: "); print_gimple_stmt (dump_file, stmt, 0, 0); fprintf (dump_file, "\nWith known ranges\n"); FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE) { fprintf (dump_file, "\t"); print_generic_expr (dump_file, use, 0); fprintf (dump_file, ": "); dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]); } fprintf (dump_file, "\n"); } /* Compute the value of the predicate COND by checking the known ranges of each of its operands. Note that we cannot evaluate all the equivalent ranges here because those ranges may not yet be final and with the current propagation strategy, we cannot determine when the value ranges of the names in the equivalence set have changed. For instance, given the following code fragment i_5 = PHI <8, i_13> ... i_14 = ASSERT_EXPR <i_5, i_5 != 0> if (i_14 == 1) ... Assume that on the first visit to i_14, i_5 has the temporary range [8, 8] because the second argument to the PHI function is not yet executable. We derive the range ~[0, 0] for i_14 and the equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for the first time, since i_14 is equivalent to the range [8, 8], we determine that the predicate is always false. On the next round of propagation, i_13 is determined to be VARYING, which causes i_5 to drop down to VARYING. So, another visit to i_14 is scheduled. In this second visit, we compute the exact same range and equivalence set for i_14, namely ~[0, 0] and { i_5 }. But we did not have the previous range for i_5 registered, so vrp_visit_assignment thinks that the range for i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)' is not visited again, which stops propagation from visiting statements in the THEN clause of that if(). To properly fix this we would need to keep the previous range value for the names in the equivalence set. This way we would've discovered that from one visit to the other i_5 changed from range [8, 8] to VR_VARYING. However, fixing this apparent limitation may not be worth the additional checking. Testing on several code bases (GCC, DLV, MICO, TRAMP3D and SPEC2000) showed that doing this results in 4 more predicates folded in SPEC. */ sop = false; val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt), gimple_cond_lhs (stmt), gimple_cond_rhs (stmt), false, &sop, NULL); if (val) { if (!sop) *taken_edge_p = find_taken_edge (gimple_bb (stmt), val); else { if (dump_file && (dump_flags & TDF_DETAILS)) fprintf (dump_file, "\nIgnoring predicate evaluation because " "it assumes that signed overflow is undefined"); val = NULL_TREE; } } if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "\nPredicate evaluates to: "); if (val == NULL_TREE) fprintf (dump_file, "DON'T KNOW\n"); else print_generic_stmt (dump_file, val, 0); } } /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL that includes the value VAL. The search is restricted to the range [START_IDX, n - 1] where n is the size of VEC. If there is a CASE_LABEL for VAL, its index is placed in IDX and true is returned. If there is no CASE_LABEL for VAL and there is one that is larger than VAL, it is placed in IDX and false is returned. If VAL is larger than any CASE_LABEL, n is placed on IDX and false is returned. */ static bool find_case_label_index (gswitch *stmt, size_t start_idx, tree val, size_t *idx) { size_t n = gimple_switch_num_labels (stmt); size_t low, high; /* Find case label for minimum of the value range or the next one. At each iteration we are searching in [low, high - 1]. */ for (low = start_idx, high = n; high != low; ) { tree t; int cmp; /* Note that i != high, so we never ask for n. */ size_t i = (high + low) / 2; t = gimple_switch_label (stmt, i); /* Cache the result of comparing CASE_LOW and val. */ cmp = tree_int_cst_compare (CASE_LOW (t), val); if (cmp == 0) { /* Ranges cannot be empty. */ *idx = i; return true; } else if (cmp > 0) high = i; else { low = i + 1; if (CASE_HIGH (t) != NULL && tree_int_cst_compare (CASE_HIGH (t), val) >= 0) { *idx = i; return true; } } } *idx = high; return false; } /* Searches the case label vector VEC for the range of CASE_LABELs that is used for values between MIN and MAX. The first index is placed in MIN_IDX. The last index is placed in MAX_IDX. If the range of CASE_LABELs is empty then MAX_IDX < MIN_IDX. Returns true if the default label is not needed. */ static bool find_case_label_range (gswitch *stmt, tree min, tree max, size_t *min_idx, size_t *max_idx) { size_t i, j; bool min_take_default = !find_case_label_index (stmt, 1, min, &i); bool max_take_default = !find_case_label_index (stmt, i, max, &j); if (i == j && min_take_default && max_take_default) { /* Only the default case label reached. Return an empty range. */ *min_idx = 1; *max_idx = 0; return false; } else { bool take_default = min_take_default || max_take_default; tree low, high; size_t k; if (max_take_default) j--; /* If the case label range is continuous, we do not need the default case label. Verify that. */ high = CASE_LOW (gimple_switch_label (stmt, i)); if (CASE_HIGH (gimple_switch_label (stmt, i))) high = CASE_HIGH (gimple_switch_label (stmt, i)); for (k = i + 1; k <= j; ++k) { low = CASE_LOW (gimple_switch_label (stmt, k)); if (!integer_onep (int_const_binop (MINUS_EXPR, low, high))) { take_default = true; break; } high = low; if (CASE_HIGH (gimple_switch_label (stmt, k))) high = CASE_HIGH (gimple_switch_label (stmt, k)); } *min_idx = i; *max_idx = j; return !take_default; } } /* Searches the case label vector VEC for the ranges of CASE_LABELs that are used in range VR. The indices are placed in MIN_IDX1, MAX_IDX, MIN_IDX2 and MAX_IDX2. If the ranges of CASE_LABELs are empty then MAX_IDX1 < MIN_IDX1. Returns true if the default label is not needed. */ static bool find_case_label_ranges (gswitch *stmt, value_range *vr, size_t *min_idx1, size_t *max_idx1, size_t *min_idx2, size_t *max_idx2) { size_t i, j, k, l; unsigned int n = gimple_switch_num_labels (stmt); bool take_default; tree case_low, case_high; tree min = vr->min, max = vr->max; gcc_checking_assert (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE); take_default = !find_case_label_range (stmt, min, max, &i, &j); /* Set second range to emtpy. */ *min_idx2 = 1; *max_idx2 = 0; if (vr->type == VR_RANGE) { *min_idx1 = i; *max_idx1 = j; return !take_default; } /* Set first range to all case labels. */ *min_idx1 = 1; *max_idx1 = n - 1; if (i > j) return false; /* Make sure all the values of case labels [i , j] are contained in range [MIN, MAX]. */ case_low = CASE_LOW (gimple_switch_label (stmt, i)); case_high = CASE_HIGH (gimple_switch_label (stmt, j)); if (tree_int_cst_compare (case_low, min) < 0) i += 1; if (case_high != NULL_TREE && tree_int_cst_compare (max, case_high) < 0) j -= 1; if (i > j) return false; /* If the range spans case labels [i, j], the corresponding anti-range spans the labels [1, i - 1] and [j + 1, n - 1]. */ k = j + 1; l = n - 1; if (k > l) { k = 1; l = 0; } j = i - 1; i = 1; if (i > j) { i = k; j = l; k = 1; l = 0; } *min_idx1 = i; *max_idx1 = j; *min_idx2 = k; *max_idx2 = l; return false; } /* Visit switch statement STMT. If we can determine which edge will be taken out of STMT's basic block, record it in *TAKEN_EDGE_P. Otherwise, *TAKEN_EDGE_P set to NULL. */ static void vrp_visit_switch_stmt (gswitch *stmt, edge *taken_edge_p) { tree op, val; value_range *vr; size_t i = 0, j = 0, k, l; bool take_default; *taken_edge_p = NULL; op = gimple_switch_index (stmt); if (TREE_CODE (op) != SSA_NAME) return; vr = get_value_range (op); if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "\nVisiting switch expression with operand "); print_generic_expr (dump_file, op, 0); fprintf (dump_file, " with known range "); dump_value_range (dump_file, vr); fprintf (dump_file, "\n"); } if ((vr->type != VR_RANGE && vr->type != VR_ANTI_RANGE) || symbolic_range_p (vr)) return; /* Find the single edge that is taken from the switch expression. */ take_default = !find_case_label_ranges (stmt, vr, &i, &j, &k, &l); /* Check if the range spans no CASE_LABEL. If so, we only reach the default label */ if (j < i) { gcc_assert (take_default); val = gimple_switch_default_label (stmt); } else { /* Check if labels with index i to j and maybe the default label are all reaching the same label. */ val = gimple_switch_label (stmt, i); if (take_default && CASE_LABEL (gimple_switch_default_label (stmt)) != CASE_LABEL (val)) { if (dump_file && (dump_flags & TDF_DETAILS)) fprintf (dump_file, " not a single destination for this " "range\n"); return; } for (++i; i <= j; ++i) { if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val)) { if (dump_file && (dump_flags & TDF_DETAILS)) fprintf (dump_file, " not a single destination for this " "range\n"); return; } } for (; k <= l; ++k) { if (CASE_LABEL (gimple_switch_label (stmt, k)) != CASE_LABEL (val)) { if (dump_file && (dump_flags & TDF_DETAILS)) fprintf (dump_file, " not a single destination for this " "range\n"); return; } } } *taken_edge_p = find_edge (gimple_bb (stmt), label_to_block (CASE_LABEL (val))); if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, " will take edge to "); print_generic_stmt (dump_file, CASE_LABEL (val), 0); } } /* Evaluate statement STMT. If the statement produces a useful range, set VR and corepsponding OUTPUT_P. If STMT is a conditional branch and we can determine its truth value, the taken edge is recorded in *TAKEN_EDGE_P. */ static void extract_range_from_stmt (gimple *stmt, edge *taken_edge_p, tree *output_p, value_range *vr) { if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "\nVisiting statement:\n"); print_gimple_stmt (dump_file, stmt, 0, dump_flags); } if (!stmt_interesting_for_vrp (stmt)) gcc_assert (stmt_ends_bb_p (stmt)); else if (is_gimple_assign (stmt) || is_gimple_call (stmt)) vrp_visit_assignment_or_call (stmt, output_p, vr); else if (gimple_code (stmt) == GIMPLE_COND) vrp_visit_cond_stmt (as_a <gcond *> (stmt), taken_edge_p); else if (gimple_code (stmt) == GIMPLE_SWITCH) vrp_visit_switch_stmt (as_a <gswitch *> (stmt), taken_edge_p); } /* Evaluate statement STMT. If the statement produces a useful range, return SSA_PROP_INTERESTING and record the SSA name with the interesting range into *OUTPUT_P. If STMT is a conditional branch and we can determine its truth value, the taken edge is recorded in *TAKEN_EDGE_P. If STMT produces a varying value, return SSA_PROP_VARYING. */ static enum ssa_prop_result vrp_visit_stmt (gimple *stmt, edge *taken_edge_p, tree *output_p) { value_range vr = VR_INITIALIZER; tree lhs = gimple_get_lhs (stmt); extract_range_from_stmt (stmt, taken_edge_p, output_p, &vr); if (*output_p) { if (update_value_range (*output_p, &vr)) { if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "Found new range for "); print_generic_expr (dump_file, *output_p, 0); fprintf (dump_file, ": "); dump_value_range (dump_file, &vr); fprintf (dump_file, "\n"); } if (vr.type == VR_VARYING) return SSA_PROP_VARYING; return SSA_PROP_INTERESTING; } return SSA_PROP_NOT_INTERESTING; } if (is_gimple_call (stmt) && gimple_call_internal_p (stmt)) switch (gimple_call_internal_fn (stmt)) { case IFN_ADD_OVERFLOW: case IFN_SUB_OVERFLOW: case IFN_MUL_OVERFLOW: /* These internal calls return _Complex integer type, which VRP does not track, but the immediate uses thereof might be interesting. */ if (lhs && TREE_CODE (lhs) == SSA_NAME) { imm_use_iterator iter; use_operand_p use_p; enum ssa_prop_result res = SSA_PROP_VARYING; set_value_range_to_varying (get_value_range (lhs)); FOR_EACH_IMM_USE_FAST (use_p, iter, lhs) { gimple *use_stmt = USE_STMT (use_p); if (!is_gimple_assign (use_stmt)) continue; enum tree_code rhs_code = gimple_assign_rhs_code (use_stmt); if (rhs_code != REALPART_EXPR && rhs_code != IMAGPART_EXPR) continue; tree rhs1 = gimple_assign_rhs1 (use_stmt); tree use_lhs = gimple_assign_lhs (use_stmt); if (TREE_CODE (rhs1) != rhs_code || TREE_OPERAND (rhs1, 0) != lhs || TREE_CODE (use_lhs) != SSA_NAME || !stmt_interesting_for_vrp (use_stmt) || (!INTEGRAL_TYPE_P (TREE_TYPE (use_lhs)) || !TYPE_MIN_VALUE (TREE_TYPE (use_lhs)) || !TYPE_MAX_VALUE (TREE_TYPE (use_lhs)))) continue; /* If there is a change in the value range for any of the REALPART_EXPR/IMAGPART_EXPR immediate uses, return SSA_PROP_INTERESTING. If there are any REALPART_EXPR or IMAGPART_EXPR immediate uses, but none of them have a change in their value ranges, return SSA_PROP_NOT_INTERESTING. If there are no {REAL,IMAG}PART_EXPR uses at all, return SSA_PROP_VARYING. */ value_range new_vr = VR_INITIALIZER; extract_range_basic (&new_vr, use_stmt); value_range *old_vr = get_value_range (use_lhs); if (old_vr->type != new_vr.type || !vrp_operand_equal_p (old_vr->min, new_vr.min) || !vrp_operand_equal_p (old_vr->max, new_vr.max) || !vrp_bitmap_equal_p (old_vr->equiv, new_vr.equiv)) res = SSA_PROP_INTERESTING; else res = SSA_PROP_NOT_INTERESTING; BITMAP_FREE (new_vr.equiv); if (res == SSA_PROP_INTERESTING) { *output_p = lhs; return res; } } return res; } break; default: break; } /* All other statements produce nothing of interest for VRP, so mark their outputs varying and prevent further simulation. */ set_defs_to_varying (stmt); return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING; } /* Union the two value-ranges { *VR0TYPE, *VR0MIN, *VR0MAX } and { VR1TYPE, VR0MIN, VR0MAX } and store the result in { *VR0TYPE, *VR0MIN, *VR0MAX }. This may not be the smallest possible such range. The resulting range is not canonicalized. */ static void union_ranges (enum value_range_type *vr0type, tree *vr0min, tree *vr0max, enum value_range_type vr1type, tree vr1min, tree vr1max) { bool mineq = vrp_operand_equal_p (*vr0min, vr1min); bool maxeq = vrp_operand_equal_p (*vr0max, vr1max); /* [] is vr0, () is vr1 in the following classification comments. */ if (mineq && maxeq) { /* [( )] */ if (*vr0type == vr1type) /* Nothing to do for equal ranges. */ ; else if ((*vr0type == VR_RANGE && vr1type == VR_ANTI_RANGE) || (*vr0type == VR_ANTI_RANGE && vr1type == VR_RANGE)) { /* For anti-range with range union the result is varying. */ goto give_up; } else gcc_unreachable (); } else if (operand_less_p (*vr0max, vr1min) == 1 || operand_less_p (vr1max, *vr0min) == 1) { /* [ ] ( ) or ( ) [ ] If the ranges have an empty intersection, result of the union operation is the anti-range or if both are anti-ranges it covers all. */ if (*vr0type == VR_ANTI_RANGE && vr1type == VR_ANTI_RANGE) goto give_up; else if (*vr0type == VR_ANTI_RANGE && vr1type == VR_RANGE) ; else if (*vr0type == VR_RANGE && vr1type == VR_ANTI_RANGE) { *vr0type = vr1type; *vr0min = vr1min; *vr0max = vr1max; } else if (*vr0type == VR_RANGE && vr1type == VR_RANGE) { /* The result is the convex hull of both ranges. */ if (operand_less_p (*vr0max, vr1min) == 1) { /* If the result can be an anti-range, create one. */ if (TREE_CODE (*vr0max) == INTEGER_CST && TREE_CODE (vr1min) == INTEGER_CST && vrp_val_is_min (*vr0min) && vrp_val_is_max (vr1max)) { tree min = int_const_binop (PLUS_EXPR, *vr0max, build_int_cst (TREE_TYPE (*vr0max), 1)); tree max = int_const_binop (MINUS_EXPR, vr1min, build_int_cst (TREE_TYPE (vr1min), 1)); if (!operand_less_p (max, min)) { *vr0type = VR_ANTI_RANGE; *vr0min = min; *vr0max = max; } else *vr0max = vr1max; } else *vr0max = vr1max; } else { /* If the result can be an anti-range, create one. */ if (TREE_CODE (vr1max) == INTEGER_CST && TREE_CODE (*vr0min) == INTEGER_CST && vrp_val_is_min (vr1min) && vrp_val_is_max (*vr0max)) { tree min = int_const_binop (PLUS_EXPR, vr1max, build_int_cst (TREE_TYPE (vr1max), 1)); tree max = int_const_binop (MINUS_EXPR, *vr0min, build_int_cst (TREE_TYPE (*vr0min), 1)); if (!operand_less_p (max, min)) { *vr0type = VR_ANTI_RANGE; *vr0min = min; *vr0max = max; } else *vr0min = vr1min; } else *vr0min = vr1min; } } else gcc_unreachable (); } else if ((maxeq || operand_less_p (vr1max, *vr0max) == 1) && (mineq || operand_less_p (*vr0min, vr1min) == 1)) { /* [ ( ) ] or [( ) ] or [ ( )] */ if (*vr0type == VR_RANGE && vr1type == VR_RANGE) ; else if (*vr0type == VR_ANTI_RANGE && vr1type == VR_ANTI_RANGE) { *vr0type = vr1type; *vr0min = vr1min; *vr0max = vr1max; } else if (*vr0type == VR_ANTI_RANGE && vr1type == VR_RANGE) { /* Arbitrarily choose the right or left gap. */ if (!mineq && TREE_CODE (vr1min) == INTEGER_CST) *vr0max = int_const_binop (MINUS_EXPR, vr1min, build_int_cst (TREE_TYPE (vr1min), 1)); else if (!maxeq && TREE_CODE (vr1max) == INTEGER_CST) *vr0min = int_const_binop (PLUS_EXPR, vr1max, build_int_cst (TREE_TYPE (vr1max), 1)); else goto give_up; } else if (*vr0type == VR_RANGE && vr1type == VR_ANTI_RANGE) /* The result covers everything. */ goto give_up; else gcc_unreachable (); } else if ((maxeq || operand_less_p (*vr0max, vr1max) == 1) && (mineq || operand_less_p (vr1min, *vr0min) == 1)) { /* ( [ ] ) or ([ ] ) or ( [ ]) */ if (*vr0type == VR_RANGE && vr1type == VR_RANGE) { *vr0type = vr1type; *vr0min = vr1min; *vr0max = vr1max; } else if (*vr0type == VR_ANTI_RANGE && vr1type == VR_ANTI_RANGE) ; else if (*vr0type == VR_RANGE && vr1type == VR_ANTI_RANGE) { *vr0type = VR_ANTI_RANGE; if (!mineq && TREE_CODE (*vr0min) == INTEGER_CST) { *vr0max = int_const_binop (MINUS_EXPR, *vr0min, build_int_cst (TREE_TYPE (*vr0min), 1)); *vr0min = vr1min; } else if (!maxeq && TREE_CODE (*vr0max) == INTEGER_CST) { *vr0min = int_const_binop (PLUS_EXPR, *vr0max, build_int_cst (TREE_TYPE (*vr0max), 1)); *vr0max = vr1max; } else goto give_up; } else if (*vr0type == VR_ANTI_RANGE && vr1type == VR_RANGE) /* The result covers everything. */ goto give_up; else gcc_unreachable (); } else if ((operand_less_p (vr1min, *vr0max) == 1 || operand_equal_p (vr1min, *vr0max, 0)) && operand_less_p (*vr0min, vr1min) == 1 && operand_less_p (*vr0max, vr1max) == 1) { /* [ ( ] ) or [ ]( ) */ if (*vr0type == VR_RANGE && vr1type == VR_RANGE) *vr0max = vr1max; else if (*vr0type == VR_ANTI_RANGE && vr1type == VR_ANTI_RANGE) *vr0min = vr1min; else if (*vr0type == VR_ANTI_RANGE && vr1type == VR_RANGE) { if (TREE_CODE (vr1min) == INTEGER_CST) *vr0max = int_const_binop (MINUS_EXPR, vr1min, build_int_cst (TREE_TYPE (vr1min), 1)); else goto give_up; } else if (*vr0type == VR_RANGE && vr1type == VR_ANTI_RANGE) { if (TREE_CODE (*vr0max) == INTEGER_CST) { *vr0type = vr1type; *vr0min = int_const_binop (PLUS_EXPR, *vr0max, build_int_cst (TREE_TYPE (*vr0max), 1)); *vr0max = vr1max; } else goto give_up; } else gcc_unreachable (); } else if ((operand_less_p (*vr0min, vr1max) == 1 || operand_equal_p (*vr0min, vr1max, 0)) && operand_less_p (vr1min, *vr0min) == 1 && operand_less_p (vr1max, *vr0max) == 1) { /* ( [ ) ] or ( )[ ] */ if (*vr0type == VR_RANGE && vr1type == VR_RANGE) *vr0min = vr1min; else if (*vr0type == VR_ANTI_RANGE && vr1type == VR_ANTI_RANGE) *vr0max = vr1max; else if (*vr0type == VR_ANTI_RANGE && vr1type == VR_RANGE) { if (TREE_CODE (vr1max) == INTEGER_CST) *vr0min = int_const_binop (PLUS_EXPR, vr1max, build_int_cst (TREE_TYPE (vr1max), 1)); else goto give_up; } else if (*vr0type == VR_RANGE && vr1type == VR_ANTI_RANGE) { if (TREE_CODE (*vr0min) == INTEGER_CST) { *vr0type = vr1type; *vr0min = vr1min; *vr0max = int_const_binop (MINUS_EXPR, *vr0min, build_int_cst (TREE_TYPE (*vr0min), 1)); } else goto give_up; } else gcc_unreachable (); } else goto give_up; return; give_up: *vr0type = VR_VARYING; *vr0min = NULL_TREE; *vr0max = NULL_TREE; } /* Intersect the two value-ranges { *VR0TYPE, *VR0MIN, *VR0MAX } and { VR1TYPE, VR0MIN, VR0MAX } and store the result in { *VR0TYPE, *VR0MIN, *VR0MAX }. This may not be the smallest possible such range. The resulting range is not canonicalized. */ static void intersect_ranges (enum value_range_type *vr0type, tree *vr0min, tree *vr0max, enum value_range_type vr1type, tree vr1min, tree vr1max) { bool mineq = vrp_operand_equal_p (*vr0min, vr1min); bool maxeq = vrp_operand_equal_p (*vr0max, vr1max); /* [] is vr0, () is vr1 in the following classification comments. */ if (mineq && maxeq) { /* [( )] */ if (*vr0type == vr1type) /* Nothing to do for equal ranges. */ ; else if ((*vr0type == VR_RANGE && vr1type == VR_ANTI_RANGE) || (*vr0type == VR_ANTI_RANGE && vr1type == VR_RANGE)) { /* For anti-range with range intersection the result is empty. */ *vr0type = VR_UNDEFINED; *vr0min = NULL_TREE; *vr0max = NULL_TREE; } else gcc_unreachable (); } else if (operand_less_p (*vr0max, vr1min) == 1 || operand_less_p (vr1max, *vr0min) == 1) { /* [ ] ( ) or ( ) [ ] If the ranges have an empty intersection, the result of the intersect operation is the range for intersecting an anti-range with a range or empty when intersecting two ranges. */ if (*vr0type == VR_RANGE && vr1type == VR_ANTI_RANGE) ; else if (*vr0type == VR_ANTI_RANGE && vr1type == VR_RANGE) { *vr0type = vr1type; *vr0min = vr1min; *vr0max = vr1max; } else if (*vr0type == VR_RANGE && vr1type == VR_RANGE) { *vr0type = VR_UNDEFINED; *vr0min = NULL_TREE; *vr0max = NULL_TREE; } else if (*vr0type == VR_ANTI_RANGE && vr1type == VR_ANTI_RANGE) { /* If the anti-ranges are adjacent to each other merge them. */ if (TREE_CODE (*vr0max) == INTEGER_CST && TREE_CODE (vr1min) == INTEGER_CST && operand_less_p (*vr0max, vr1min) == 1 && integer_onep (int_const_binop (MINUS_EXPR, vr1min, *vr0max))) *vr0max = vr1max; else if (TREE_CODE (vr1max) == INTEGER_CST && TREE_CODE (*vr0min) == INTEGER_CST && operand_less_p (vr1max, *vr0min) == 1 && integer_onep (int_const_binop (MINUS_EXPR, *vr0min, vr1max))) *vr0min = vr1min; /* Else arbitrarily take VR0. */ } } else if ((maxeq || operand_less_p (vr1max, *vr0max) == 1) && (mineq || operand_less_p (*vr0min, vr1min) == 1)) { /* [ ( ) ] or [( ) ] or [ ( )] */ if (*vr0type == VR_RANGE && vr1type == VR_RANGE) { /* If both are ranges the result is the inner one. */ *vr0type = vr1type; *vr0min = vr1min; *vr0max = vr1max; } else if (*vr0type == VR_RANGE && vr1type == VR_ANTI_RANGE) { /* Choose the right gap if the left one is empty. */ if (mineq) { if (TREE_CODE (vr1max) == INTEGER_CST) *vr0min = int_const_binop (PLUS_EXPR, vr1max, build_int_cst (TREE_TYPE (vr1max), 1)); else *vr0min = vr1max; } /* Choose the left gap if the right one is empty. */ else if (maxeq) { if (TREE_CODE (vr1min) == INTEGER_CST) *vr0max = int_const_binop (MINUS_EXPR, vr1min, build_int_cst (TREE_TYPE (vr1min), 1)); else *vr0max = vr1min; } /* Choose the anti-range if the range is effectively varying. */ else if (vrp_val_is_min (*vr0min) && vrp_val_is_max (*vr0max)) { *vr0type = vr1type; *vr0min = vr1min; *vr0max = vr1max; } /* Else choose the range. */ } else if (*vr0type == VR_ANTI_RANGE && vr1type == VR_ANTI_RANGE) /* If both are anti-ranges the result is the outer one. */ ; else if (*vr0type == VR_ANTI_RANGE && vr1type == VR_RANGE) { /* The intersection is empty. */ *vr0type = VR_UNDEFINED; *vr0min = NULL_TREE; *vr0max = NULL_TREE; } else gcc_unreachable (); } else if ((maxeq || operand_less_p (*vr0max, vr1max) == 1) && (mineq || operand_less_p (vr1min, *vr0min) == 1)) { /* ( [ ] ) or ([ ] ) or ( [ ]) */ if (*vr0type == VR_RANGE && vr1type == VR_RANGE) /* Choose the inner range. */ ; else if (*vr0type == VR_ANTI_RANGE && vr1type == VR_RANGE) { /* Choose the right gap if the left is empty. */ if (mineq) { *vr0type = VR_RANGE; if (TREE_CODE (*vr0max) == INTEGER_CST) *vr0min = int_const_binop (PLUS_EXPR, *vr0max, build_int_cst (TREE_TYPE (*vr0max), 1)); else *vr0min = *vr0max; *vr0max = vr1max; } /* Choose the left gap if the right is empty. */ else if (maxeq) { *vr0type = VR_RANGE; if (TREE_CODE (*vr0min) == INTEGER_CST) *vr0max = int_const_binop (MINUS_EXPR, *vr0min, build_int_cst (TREE_TYPE (*vr0min), 1)); else *vr0max = *vr0min; *vr0min = vr1min; } /* Choose the anti-range if the range is effectively varying. */ else if (vrp_val_is_min (vr1min) && vrp_val_is_max (vr1max)) ; /* Else choose the range. */ else { *vr0type = vr1type; *vr0min = vr1min; *vr0max = vr1max; } } else if (*vr0type == VR_ANTI_RANGE && vr1type == VR_ANTI_RANGE) { /* If both are anti-ranges the result is the outer one. */ *vr0type = vr1type; *vr0min = vr1min; *vr0max = vr1max; } else if (vr1type == VR_ANTI_RANGE && *vr0type == VR_RANGE) { /* The intersection is empty. */ *vr0type = VR_UNDEFINED; *vr0min = NULL_TREE; *vr0max = NULL_TREE; } else gcc_unreachable (); } else if ((operand_less_p (vr1min, *vr0max) == 1 || operand_equal_p (vr1min, *vr0max, 0)) && operand_less_p (*vr0min, vr1min) == 1) { /* [ ( ] ) or [ ]( ) */ if (*vr0type == VR_ANTI_RANGE && vr1type == VR_ANTI_RANGE) *vr0max = vr1max; else if (*vr0type == VR_RANGE && vr1type == VR_RANGE) *vr0min = vr1min; else if (*vr0type == VR_RANGE && vr1type == VR_ANTI_RANGE) { if (TREE_CODE (vr1min) == INTEGER_CST) *vr0max = int_const_binop (MINUS_EXPR, vr1min, build_int_cst (TREE_TYPE (vr1min), 1)); else *vr0max = vr1min; } else if (*vr0type == VR_ANTI_RANGE && vr1type == VR_RANGE) { *vr0type = VR_RANGE; if (TREE_CODE (*vr0max) == INTEGER_CST) *vr0min = int_const_binop (PLUS_EXPR, *vr0max, build_int_cst (TREE_TYPE (*vr0max), 1)); else *vr0min = *vr0max; *vr0max = vr1max; } else gcc_unreachable (); } else if ((operand_less_p (*vr0min, vr1max) == 1 || operand_equal_p (*vr0min, vr1max, 0)) && operand_less_p (vr1min, *vr0min) == 1) { /* ( [ ) ] or ( )[ ] */ if (*vr0type == VR_ANTI_RANGE && vr1type == VR_ANTI_RANGE) *vr0min = vr1min; else if (*vr0type == VR_RANGE && vr1type == VR_RANGE) *vr0max = vr1max; else if (*vr0type == VR_RANGE && vr1type == VR_ANTI_RANGE) { if (TREE_CODE (vr1max) == INTEGER_CST) *vr0min = int_const_binop (PLUS_EXPR, vr1max, build_int_cst (TREE_TYPE (vr1max), 1)); else *vr0min = vr1max; } else if (*vr0type == VR_ANTI_RANGE && vr1type == VR_RANGE) { *vr0type = VR_RANGE; if (TREE_CODE (*vr0min) == INTEGER_CST) *vr0max = int_const_binop (MINUS_EXPR, *vr0min, build_int_cst (TREE_TYPE (*vr0min), 1)); else *vr0max = *vr0min; *vr0min = vr1min; } else gcc_unreachable (); } /* As a fallback simply use { *VRTYPE, *VR0MIN, *VR0MAX } as result for the intersection. That's always a conservative correct estimate unless VR1 is a constant singleton range in which case we choose that. */ if (vr1type == VR_RANGE && is_gimple_min_invariant (vr1min) && vrp_operand_equal_p (vr1min, vr1max)) { *vr0type = vr1type; *vr0min = vr1min; *vr0max = vr1max; } return; } /* Intersect the two value-ranges *VR0 and *VR1 and store the result in *VR0. This may not be the smallest possible such range. */ static void vrp_intersect_ranges_1 (value_range *vr0, value_range *vr1) { value_range saved; /* If either range is VR_VARYING the other one wins. */ if (vr1->type == VR_VARYING) return; if (vr0->type == VR_VARYING) { copy_value_range (vr0, vr1); return; } /* When either range is VR_UNDEFINED the resulting range is VR_UNDEFINED, too. */ if (vr0->type == VR_UNDEFINED) return; if (vr1->type == VR_UNDEFINED) { set_value_range_to_undefined (vr0); return; } /* Save the original vr0 so we can return it as conservative intersection result when our worker turns things to varying. */ saved = *vr0; intersect_ranges (&vr0->type, &vr0->min, &vr0->max, vr1->type, vr1->min, vr1->max); /* Make sure to canonicalize the result though as the inversion of a VR_RANGE can still be a VR_RANGE. */ set_and_canonicalize_value_range (vr0, vr0->type, vr0->min, vr0->max, vr0->equiv); /* If that failed, use the saved original VR0. */ if (vr0->type == VR_VARYING) { *vr0 = saved; return; } /* If the result is VR_UNDEFINED there is no need to mess with the equivalencies. */ if (vr0->type == VR_UNDEFINED) return; /* The resulting set of equivalences for range intersection is the union of the two sets. */ if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv) bitmap_ior_into (vr0->equiv, vr1->equiv); else if (vr1->equiv && !vr0->equiv) { vr0->equiv = BITMAP_ALLOC (&vrp_equiv_obstack); bitmap_copy (vr0->equiv, vr1->equiv); } } void vrp_intersect_ranges (value_range *vr0, value_range *vr1) { if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "Intersecting\n "); dump_value_range (dump_file, vr0); fprintf (dump_file, "\nand\n "); dump_value_range (dump_file, vr1); fprintf (dump_file, "\n"); } vrp_intersect_ranges_1 (vr0, vr1); if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "to\n "); dump_value_range (dump_file, vr0); fprintf (dump_file, "\n"); } } /* Meet operation for value ranges. Given two value ranges VR0 and VR1, store in VR0 a range that contains both VR0 and VR1. This may not be the smallest possible such range. */ static void vrp_meet_1 (value_range *vr0, const value_range *vr1) { value_range saved; if (vr0->type == VR_UNDEFINED) { set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr1->equiv); return; } if (vr1->type == VR_UNDEFINED) { /* VR0 already has the resulting range. */ return; } if (vr0->type == VR_VARYING) { /* Nothing to do. VR0 already has the resulting range. */ return; } if (vr1->type == VR_VARYING) { set_value_range_to_varying (vr0); return; } saved = *vr0; union_ranges (&vr0->type, &vr0->min, &vr0->max, vr1->type, vr1->min, vr1->max); if (vr0->type == VR_VARYING) { /* Failed to find an efficient meet. Before giving up and setting the result to VARYING, see if we can at least derive a useful anti-range. FIXME, all this nonsense about distinguishing anti-ranges from ranges is necessary because of the odd semantics of range_includes_zero_p and friends. */ if (((saved.type == VR_RANGE && range_includes_zero_p (saved.min, saved.max) == 0) || (saved.type == VR_ANTI_RANGE && range_includes_zero_p (saved.min, saved.max) == 1)) && ((vr1->type == VR_RANGE && range_includes_zero_p (vr1->min, vr1->max) == 0) || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1->min, vr1->max) == 1))) { set_value_range_to_nonnull (vr0, TREE_TYPE (saved.min)); /* Since this meet operation did not result from the meeting of two equivalent names, VR0 cannot have any equivalences. */ if (vr0->equiv) bitmap_clear (vr0->equiv); return; } set_value_range_to_varying (vr0); return; } set_and_canonicalize_value_range (vr0, vr0->type, vr0->min, vr0->max, vr0->equiv); if (vr0->type == VR_VARYING) return; /* The resulting set of equivalences is always the intersection of the two sets. */ if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv) bitmap_and_into (vr0->equiv, vr1->equiv); else if (vr0->equiv && !vr1->equiv) bitmap_clear (vr0->equiv); } void vrp_meet (value_range *vr0, const value_range *vr1) { if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "Meeting\n "); dump_value_range (dump_file, vr0); fprintf (dump_file, "\nand\n "); dump_value_range (dump_file, vr1); fprintf (dump_file, "\n"); } vrp_meet_1 (vr0, vr1); if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "to\n "); dump_value_range (dump_file, vr0); fprintf (dump_file, "\n"); } } /* Visit all arguments for PHI node PHI that flow through executable edges. If a valid value range can be derived from all the incoming value ranges, set a new range in VR_RESULT. */ static void extract_range_from_phi_node (gphi *phi, value_range *vr_result) { size_t i; tree lhs = PHI_RESULT (phi); value_range *lhs_vr = get_value_range (lhs); bool first = true; int edges, old_edges; struct loop *l; if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "\nVisiting PHI node: "); print_gimple_stmt (dump_file, phi, 0, dump_flags); } bool may_simulate_backedge_again = false; edges = 0; for (i = 0; i < gimple_phi_num_args (phi); i++) { edge e = gimple_phi_arg_edge (phi, i); if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, " Argument #%d (%d -> %d %sexecutable)\n", (int) i, e->src->index, e->dest->index, (e->flags & EDGE_EXECUTABLE) ? "" : "not "); } if (e->flags & EDGE_EXECUTABLE) { tree arg = PHI_ARG_DEF (phi, i); value_range vr_arg; ++edges; if (TREE_CODE (arg) == SSA_NAME) { /* See if we are eventually going to change one of the args. */ gimple *def_stmt = SSA_NAME_DEF_STMT (arg); if (! gimple_nop_p (def_stmt) && prop_simulate_again_p (def_stmt) && e->flags & EDGE_DFS_BACK) may_simulate_backedge_again = true; vr_arg = *(get_value_range (arg)); /* Do not allow equivalences or symbolic ranges to leak in from backedges. That creates invalid equivalencies. See PR53465 and PR54767. */ if (e->flags & EDGE_DFS_BACK) { if (vr_arg.type == VR_RANGE || vr_arg.type == VR_ANTI_RANGE) { vr_arg.equiv = NULL; if (symbolic_range_p (&vr_arg)) { vr_arg.type = VR_VARYING; vr_arg.min = NULL_TREE; vr_arg.max = NULL_TREE; } } } else { /* If the non-backedge arguments range is VR_VARYING then we can still try recording a simple equivalence. */ if (vr_arg.type == VR_VARYING) { vr_arg.type = VR_RANGE; vr_arg.min = arg; vr_arg.max = arg; vr_arg.equiv = NULL; } } } else { if (TREE_OVERFLOW_P (arg)) arg = drop_tree_overflow (arg); vr_arg.type = VR_RANGE; vr_arg.min = arg; vr_arg.max = arg; vr_arg.equiv = NULL; } if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "\t"); print_generic_expr (dump_file, arg, dump_flags); fprintf (dump_file, ": "); dump_value_range (dump_file, &vr_arg); fprintf (dump_file, "\n"); } if (first) copy_value_range (vr_result, &vr_arg); else vrp_meet (vr_result, &vr_arg); first = false; if (vr_result->type == VR_VARYING) break; } } if (vr_result->type == VR_VARYING) goto varying; else if (vr_result->type == VR_UNDEFINED) goto update_range; old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)]; vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges; /* To prevent infinite iterations in the algorithm, derive ranges when the new value is slightly bigger or smaller than the previous one. We don't do this if we have seen a new executable edge; this helps us avoid an overflow infinity for conditionals which are not in a loop. If the old value-range was VR_UNDEFINED use the updated range and iterate one more time. If we will not simulate this PHI again via the backedge allow us to iterate. */ if (edges > 0 && gimple_phi_num_args (phi) > 1 && edges == old_edges && lhs_vr->type != VR_UNDEFINED && may_simulate_backedge_again) { /* Compare old and new ranges, fall back to varying if the values are not comparable. */ int cmp_min = compare_values (lhs_vr->min, vr_result->min); if (cmp_min == -2) goto varying; int cmp_max = compare_values (lhs_vr->max, vr_result->max); if (cmp_max == -2) goto varying; /* For non VR_RANGE or for pointers fall back to varying if the range changed. */ if ((lhs_vr->type != VR_RANGE || vr_result->type != VR_RANGE || POINTER_TYPE_P (TREE_TYPE (lhs))) && (cmp_min != 0 || cmp_max != 0)) goto varying; /* If the new minimum is larger than the previous one retain the old value. If the new minimum value is smaller than the previous one and not -INF go all the way to -INF + 1. In the first case, to avoid infinite bouncing between different minimums, and in the other case to avoid iterating millions of times to reach -INF. Going to -INF + 1 also lets the following iteration compute whether there will be any overflow, at the expense of one additional iteration. */ if (cmp_min < 0) vr_result->min = lhs_vr->min; else if (cmp_min > 0 && !vrp_val_is_min (vr_result->min)) vr_result->min = int_const_binop (PLUS_EXPR, vrp_val_min (TREE_TYPE (vr_result->min)), build_int_cst (TREE_TYPE (vr_result->min), 1)); /* Similarly for the maximum value. */ if (cmp_max > 0) vr_result->max = lhs_vr->max; else if (cmp_max < 0 && !vrp_val_is_max (vr_result->max)) vr_result->max = int_const_binop (MINUS_EXPR, vrp_val_max (TREE_TYPE (vr_result->min)), build_int_cst (TREE_TYPE (vr_result->min), 1)); /* If we dropped either bound to +-INF then if this is a loop PHI node SCEV may known more about its value-range. */ if (cmp_min > 0 || cmp_min < 0 || cmp_max < 0 || cmp_max > 0) goto scev_check; goto infinite_check; } goto update_range; varying: set_value_range_to_varying (vr_result); scev_check: /* If this is a loop PHI node SCEV may known more about its value-range. scev_check can be reached from two paths, one is a fall through from above "varying" label, the other is direct goto from code block which tries to avoid infinite simulation. */ if ((l = loop_containing_stmt (phi)) && l->header == gimple_bb (phi)) adjust_range_with_scev (vr_result, l, phi, lhs); infinite_check: /* If we will end up with a (-INF, +INF) range, set it to VARYING. Same if the previous max value was invalid for the type and we end up with vr_result.min > vr_result.max. */ if ((vr_result->type == VR_RANGE || vr_result->type == VR_ANTI_RANGE) && !((vrp_val_is_max (vr_result->max) && vrp_val_is_min (vr_result->min)) || compare_values (vr_result->min, vr_result->max) > 0)) ; else set_value_range_to_varying (vr_result); /* If the new range is different than the previous value, keep iterating. */ update_range: return; } /* Visit all arguments for PHI node PHI that flow through executable edges. If a valid value range can be derived from all the incoming value ranges, set a new range for the LHS of PHI. */ static enum ssa_prop_result vrp_visit_phi_node (gphi *phi) { tree lhs = PHI_RESULT (phi); value_range vr_result = VR_INITIALIZER; extract_range_from_phi_node (phi, &vr_result); if (update_value_range (lhs, &vr_result)) { if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "Found new range for "); print_generic_expr (dump_file, lhs, 0); fprintf (dump_file, ": "); dump_value_range (dump_file, &vr_result); fprintf (dump_file, "\n"); } if (vr_result.type == VR_VARYING) return SSA_PROP_VARYING; return SSA_PROP_INTERESTING; } /* Nothing changed, don't add outgoing edges. */ return SSA_PROP_NOT_INTERESTING; } /* Simplify boolean operations if the source is known to be already a boolean. */ static bool simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple *stmt) { enum tree_code rhs_code = gimple_assign_rhs_code (stmt); tree lhs, op0, op1; bool need_conversion; /* We handle only !=/== case here. */ gcc_assert (rhs_code == EQ_EXPR || rhs_code == NE_EXPR); op0 = gimple_assign_rhs1 (stmt); if (!op_with_boolean_value_range_p (op0)) return false; op1 = gimple_assign_rhs2 (stmt); if (!op_with_boolean_value_range_p (op1)) return false; /* Reduce number of cases to handle to NE_EXPR. As there is no BIT_XNOR_EXPR we cannot replace A == B with a single statement. */ if (rhs_code == EQ_EXPR) { if (TREE_CODE (op1) == INTEGER_CST) op1 = int_const_binop (BIT_XOR_EXPR, op1, build_int_cst (TREE_TYPE (op1), 1)); else return false; } lhs = gimple_assign_lhs (stmt); need_conversion = !useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (op0)); /* Make sure to not sign-extend a 1-bit 1 when converting the result. */ if (need_conversion && !TYPE_UNSIGNED (TREE_TYPE (op0)) && TYPE_PRECISION (TREE_TYPE (op0)) == 1 && TYPE_PRECISION (TREE_TYPE (lhs)) > 1) return false; /* For A != 0 we can substitute A itself. */ if (integer_zerop (op1)) gimple_assign_set_rhs_with_ops (gsi, need_conversion ? NOP_EXPR : TREE_CODE (op0), op0); /* For A != B we substitute A ^ B. Either with conversion. */ else if (need_conversion) { tree tem = make_ssa_name (TREE_TYPE (op0)); gassign *newop = gimple_build_assign (tem, BIT_XOR_EXPR, op0, op1); gsi_insert_before (gsi, newop, GSI_SAME_STMT); if (INTEGRAL_TYPE_P (TREE_TYPE (tem)) && TYPE_PRECISION (TREE_TYPE (tem)) > 1) set_range_info (tem, VR_RANGE, wi::zero (TYPE_PRECISION (TREE_TYPE (tem))), wi::one (TYPE_PRECISION (TREE_TYPE (tem)))); gimple_assign_set_rhs_with_ops (gsi, NOP_EXPR, tem); } /* Or without. */ else gimple_assign_set_rhs_with_ops (gsi, BIT_XOR_EXPR, op0, op1); update_stmt (gsi_stmt (*gsi)); fold_stmt (gsi, follow_single_use_edges); return true; } /* Simplify a division or modulo operator to a right shift or bitwise and if the first operand is unsigned or is greater than zero and the second operand is an exact power of two. For TRUNC_MOD_EXPR op0 % op1 with constant op1, optimize it into just op0 if op0's range is known to be a subset of [-op1 + 1, op1 - 1] for signed and [0, op1 - 1] for unsigned modulo. */ static bool simplify_div_or_mod_using_ranges (gimple_stmt_iterator *gsi, gimple *stmt) { enum tree_code rhs_code = gimple_assign_rhs_code (stmt); tree val = NULL; tree op0 = gimple_assign_rhs1 (stmt); tree op1 = gimple_assign_rhs2 (stmt); value_range *vr = get_value_range (op0); if (rhs_code == TRUNC_MOD_EXPR && TREE_CODE (op1) == INTEGER_CST && tree_int_cst_sgn (op1) == 1 && range_int_cst_p (vr) && tree_int_cst_lt (vr->max, op1)) { if (TYPE_UNSIGNED (TREE_TYPE (op0)) || tree_int_cst_sgn (vr->min) >= 0 || tree_int_cst_lt (fold_unary (NEGATE_EXPR, TREE_TYPE (op1), op1), vr->min)) { /* If op0 already has the range op0 % op1 has, then TRUNC_MOD_EXPR won't change anything. */ gimple_assign_set_rhs_from_tree (gsi, op0); return true; } } if (!integer_pow2p (op1)) { /* X % -Y can be only optimized into X % Y either if X is not INT_MIN, or Y is not -1. Fold it now, as after remove_range_assertions the range info might be not available anymore. */ if (rhs_code == TRUNC_MOD_EXPR && fold_stmt (gsi, follow_single_use_edges)) return true; return false; } if (TYPE_UNSIGNED (TREE_TYPE (op0))) val = integer_one_node; else { bool sop = false; val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop); if (val && sop && integer_onep (val) && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC)) { location_t location; if (!gimple_has_location (stmt)) location = input_location; else location = gimple_location (stmt); warning_at (location, OPT_Wstrict_overflow, "assuming signed overflow does not occur when " "simplifying %</%> or %<%%%> to %<>>%> or %<&%>"); } } if (val && integer_onep (val)) { tree t; if (rhs_code == TRUNC_DIV_EXPR) { t = build_int_cst (integer_type_node, tree_log2 (op1)); gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR); gimple_assign_set_rhs1 (stmt, op0); gimple_assign_set_rhs2 (stmt, t); } else { t = build_int_cst (TREE_TYPE (op1), 1); t = int_const_binop (MINUS_EXPR, op1, t); t = fold_convert (TREE_TYPE (op0), t); gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR); gimple_assign_set_rhs1 (stmt, op0); gimple_assign_set_rhs2 (stmt, t); } update_stmt (stmt); fold_stmt (gsi, follow_single_use_edges); return true; } return false; } /* Simplify a min or max if the ranges of the two operands are disjoint. Return true if we do simplify. */ static bool simplify_min_or_max_using_ranges (gimple_stmt_iterator *gsi, gimple *stmt) { tree op0 = gimple_assign_rhs1 (stmt); tree op1 = gimple_assign_rhs2 (stmt); bool sop = false; tree val; val = (vrp_evaluate_conditional_warnv_with_ops_using_ranges (LE_EXPR, op0, op1, &sop)); if (!val) { sop = false; val = (vrp_evaluate_conditional_warnv_with_ops_using_ranges (LT_EXPR, op0, op1, &sop)); } if (val) { if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC)) { location_t location; if (!gimple_has_location (stmt)) location = input_location; else location = gimple_location (stmt); warning_at (location, OPT_Wstrict_overflow, "assuming signed overflow does not occur when " "simplifying %<min/max (X,Y)%> to %<X%> or %<Y%>"); } /* VAL == TRUE -> OP0 < or <= op1 VAL == FALSE -> OP0 > or >= op1. */ tree res = ((gimple_assign_rhs_code (stmt) == MAX_EXPR) == integer_zerop (val)) ? op0 : op1; gimple_assign_set_rhs_from_tree (gsi, res); return true; } return false; } /* If the operand to an ABS_EXPR is >= 0, then eliminate the ABS_EXPR. If the operand is <= 0, then simplify the ABS_EXPR into a NEGATE_EXPR. */ static bool simplify_abs_using_ranges (gimple_stmt_iterator *gsi, gimple *stmt) { tree op = gimple_assign_rhs1 (stmt); value_range *vr = get_value_range (op); if (vr) { tree val = NULL; bool sop = false; val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop); if (!val) { /* The range is neither <= 0 nor > 0. Now see if it is either < 0 or >= 0. */ sop = false; val = compare_range_with_value (LT_EXPR, vr, integer_zero_node, &sop); } if (val) { if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC)) { location_t location; if (!gimple_has_location (stmt)) location = input_location; else location = gimple_location (stmt); warning_at (location, OPT_Wstrict_overflow, "assuming signed overflow does not occur when " "simplifying %<abs (X)%> to %<X%> or %<-X%>"); } gimple_assign_set_rhs1 (stmt, op); if (integer_zerop (val)) gimple_assign_set_rhs_code (stmt, SSA_NAME); else gimple_assign_set_rhs_code (stmt, NEGATE_EXPR); update_stmt (stmt); fold_stmt (gsi, follow_single_use_edges); return true; } } return false; } /* Optimize away redundant BIT_AND_EXPR and BIT_IOR_EXPR. If all the bits that are being cleared by & are already known to be zero from VR, or all the bits that are being set by | are already known to be one from VR, the bit operation is redundant. */ static bool simplify_bit_ops_using_ranges (gimple_stmt_iterator *gsi, gimple *stmt) { tree op0 = gimple_assign_rhs1 (stmt); tree op1 = gimple_assign_rhs2 (stmt); tree op = NULL_TREE; value_range vr0 = VR_INITIALIZER; value_range vr1 = VR_INITIALIZER; wide_int may_be_nonzero0, may_be_nonzero1; wide_int must_be_nonzero0, must_be_nonzero1; wide_int mask; if (TREE_CODE (op0) == SSA_NAME) vr0 = *(get_value_range (op0)); else if (is_gimple_min_invariant (op0)) set_value_range_to_value (&vr0, op0, NULL); else return false; if (TREE_CODE (op1) == SSA_NAME) vr1 = *(get_value_range (op1)); else if (is_gimple_min_invariant (op1)) set_value_range_to_value (&vr1, op1, NULL); else return false; if (!zero_nonzero_bits_from_vr (TREE_TYPE (op0), &vr0, &may_be_nonzero0, &must_be_nonzero0)) return false; if (!zero_nonzero_bits_from_vr (TREE_TYPE (op1), &vr1, &may_be_nonzero1, &must_be_nonzero1)) return false; switch (gimple_assign_rhs_code (stmt)) { case BIT_AND_EXPR: mask = may_be_nonzero0.and_not (must_be_nonzero1); if (mask == 0) { op = op0; break; } mask = may_be_nonzero1.and_not (must_be_nonzero0); if (mask == 0) { op = op1; break; } break; case BIT_IOR_EXPR: mask = may_be_nonzero0.and_not (must_be_nonzero1); if (mask == 0) { op = op1; break; } mask = may_be_nonzero1.and_not (must_be_nonzero0); if (mask == 0) { op = op0; break; } break; default: gcc_unreachable (); } if (op == NULL_TREE) return false; gimple_assign_set_rhs_with_ops (gsi, TREE_CODE (op), op); update_stmt (gsi_stmt (*gsi)); return true; } /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has a known value range VR. If there is one and only one value which will satisfy the conditional, then return that value. Else return NULL. If signed overflow must be undefined for the value to satisfy the conditional, then set *STRICT_OVERFLOW_P to true. */ static tree test_for_singularity (enum tree_code cond_code, tree op0, tree op1, value_range *vr, bool *strict_overflow_p) { tree min = NULL; tree max = NULL; /* Extract minimum/maximum values which satisfy the conditional as it was written. */ if (cond_code == LE_EXPR || cond_code == LT_EXPR) { /* This should not be negative infinity; there is no overflow here. */ min = TYPE_MIN_VALUE (TREE_TYPE (op0)); max = op1; if (cond_code == LT_EXPR && !is_overflow_infinity (max)) { tree one = build_int_cst (TREE_TYPE (op0), 1); max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one); if (EXPR_P (max)) TREE_NO_WARNING (max) = 1; } } else if (cond_code == GE_EXPR || cond_code == GT_EXPR) { /* This should not be positive infinity; there is no overflow here. */ max = TYPE_MAX_VALUE (TREE_TYPE (op0)); min = op1; if (cond_code == GT_EXPR && !is_overflow_infinity (min)) { tree one = build_int_cst (TREE_TYPE (op0), 1); min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one); if (EXPR_P (min)) TREE_NO_WARNING (min) = 1; } } /* Now refine the minimum and maximum values using any value range information we have for op0. */ if (min && max) { if (compare_values (vr->min, min) == 1) min = vr->min; if (compare_values (vr->max, max) == -1) max = vr->max; /* If the new min/max values have converged to a single value, then there is only one value which can satisfy the condition, return that value. */ if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min)) { if ((cond_code == LE_EXPR || cond_code == LT_EXPR) && is_overflow_infinity (vr->max)) *strict_overflow_p = true; if ((cond_code == GE_EXPR || cond_code == GT_EXPR) && is_overflow_infinity (vr->min)) *strict_overflow_p = true; return min; } } return NULL; } /* Return whether the value range *VR fits in an integer type specified by PRECISION and UNSIGNED_P. */ static bool range_fits_type_p (value_range *vr, unsigned dest_precision, signop dest_sgn) { tree src_type; unsigned src_precision; widest_int tem; signop src_sgn; /* We can only handle integral and pointer types. */ src_type = TREE_TYPE (vr->min); if (!INTEGRAL_TYPE_P (src_type) && !POINTER_TYPE_P (src_type)) return false; /* An extension is fine unless VR is SIGNED and dest_sgn is UNSIGNED, and so is an identity transform. */ src_precision = TYPE_PRECISION (TREE_TYPE (vr->min)); src_sgn = TYPE_SIGN (src_type); if ((src_precision < dest_precision && !(dest_sgn == UNSIGNED && src_sgn == SIGNED)) || (src_precision == dest_precision && src_sgn == dest_sgn)) return true; /* Now we can only handle ranges with constant bounds. */ if (vr->type != VR_RANGE || TREE_CODE (vr->min) != INTEGER_CST || TREE_CODE (vr->max) != INTEGER_CST) return false; /* For sign changes, the MSB of the wide_int has to be clear. An unsigned value with its MSB set cannot be represented by a signed wide_int, while a negative value cannot be represented by an unsigned wide_int. */ if (src_sgn != dest_sgn && (wi::lts_p (vr->min, 0) || wi::lts_p (vr->max, 0))) return false; /* Then we can perform the conversion on both ends and compare the result for equality. */ tem = wi::ext (wi::to_widest (vr->min), dest_precision, dest_sgn); if (tem != wi::to_widest (vr->min)) return false; tem = wi::ext (wi::to_widest (vr->max), dest_precision, dest_sgn); if (tem != wi::to_widest (vr->max)) return false; return true; } /* Simplify a conditional using a relational operator to an equality test if the range information indicates only one value can satisfy the original conditional. */ static bool simplify_cond_using_ranges (gcond *stmt) { tree op0 = gimple_cond_lhs (stmt); tree op1 = gimple_cond_rhs (stmt); enum tree_code cond_code = gimple_cond_code (stmt); if (cond_code != NE_EXPR && cond_code != EQ_EXPR && TREE_CODE (op0) == SSA_NAME && INTEGRAL_TYPE_P (TREE_TYPE (op0)) && is_gimple_min_invariant (op1)) { value_range *vr = get_value_range (op0); /* If we have range information for OP0, then we might be able to simplify this conditional. */ if (vr->type == VR_RANGE) { enum warn_strict_overflow_code wc = WARN_STRICT_OVERFLOW_COMPARISON; bool sop = false; tree new_tree = test_for_singularity (cond_code, op0, op1, vr, &sop); if (new_tree && (!sop || TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0)))) { if (dump_file) { fprintf (dump_file, "Simplified relational "); print_gimple_stmt (dump_file, stmt, 0, 0); fprintf (dump_file, " into "); } gimple_cond_set_code (stmt, EQ_EXPR); gimple_cond_set_lhs (stmt, op0); gimple_cond_set_rhs (stmt, new_tree); update_stmt (stmt); if (dump_file) { print_gimple_stmt (dump_file, stmt, 0, 0); fprintf (dump_file, "\n"); } if (sop && issue_strict_overflow_warning (wc)) { location_t location = input_location; if (gimple_has_location (stmt)) location = gimple_location (stmt); warning_at (location, OPT_Wstrict_overflow, "assuming signed overflow does not occur when " "simplifying conditional"); } return true; } /* Try again after inverting the condition. We only deal with integral types here, so no need to worry about issues with inverting FP comparisons. */ sop = false; new_tree = test_for_singularity (invert_tree_comparison (cond_code, false), op0, op1, vr, &sop); if (new_tree && (!sop || TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0)))) { if (dump_file) { fprintf (dump_file, "Simplified relational "); print_gimple_stmt (dump_file, stmt, 0, 0); fprintf (dump_file, " into "); } gimple_cond_set_code (stmt, NE_EXPR); gimple_cond_set_lhs (stmt, op0); gimple_cond_set_rhs (stmt, new_tree); update_stmt (stmt); if (dump_file) { print_gimple_stmt (dump_file, stmt, 0, 0); fprintf (dump_file, "\n"); } if (sop && issue_strict_overflow_warning (wc)) { location_t location = input_location; if (gimple_has_location (stmt)) location = gimple_location (stmt); warning_at (location, OPT_Wstrict_overflow, "assuming signed overflow does not occur when " "simplifying conditional"); } return true; } } } /* If we have a comparison of an SSA_NAME (OP0) against a constant, see if OP0 was set by a type conversion where the source of the conversion is another SSA_NAME with a range that fits into the range of OP0's type. If so, the conversion is redundant as the earlier SSA_NAME can be used for the comparison directly if we just massage the constant in the comparison. */ if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == INTEGER_CST) { gimple *def_stmt = SSA_NAME_DEF_STMT (op0); tree innerop; if (!is_gimple_assign (def_stmt) || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))) return false; innerop = gimple_assign_rhs1 (def_stmt); if (TREE_CODE (innerop) == SSA_NAME && !POINTER_TYPE_P (TREE_TYPE (innerop)) && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (innerop) && desired_pro_or_demotion_p (TREE_TYPE (innerop), TREE_TYPE (op0))) { value_range *vr = get_value_range (innerop); if (range_int_cst_p (vr) && range_fits_type_p (vr, TYPE_PRECISION (TREE_TYPE (op0)), TYPE_SIGN (TREE_TYPE (op0))) && int_fits_type_p (op1, TREE_TYPE (innerop)) /* The range must not have overflowed, or if it did overflow we must not be wrapping/trapping overflow and optimizing with strict overflow semantics. */ && ((!is_negative_overflow_infinity (vr->min) && !is_positive_overflow_infinity (vr->max)) || TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (innerop)))) { /* If the range overflowed and the user has asked for warnings when strict overflow semantics were used to optimize code, issue an appropriate warning. */ if (cond_code != EQ_EXPR && cond_code != NE_EXPR && (is_negative_overflow_infinity (vr->min) || is_positive_overflow_infinity (vr->max)) && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_CONDITIONAL)) { location_t location; if (!gimple_has_location (stmt)) location = input_location; else location = gimple_location (stmt); warning_at (location, OPT_Wstrict_overflow, "assuming signed overflow does not occur when " "simplifying conditional"); } tree newconst = fold_convert (TREE_TYPE (innerop), op1); gimple_cond_set_lhs (stmt, innerop); gimple_cond_set_rhs (stmt, newconst); return true; } } } return false; } /* Simplify a switch statement using the value range of the switch argument. */ static bool simplify_switch_using_ranges (gswitch *stmt) { tree op = gimple_switch_index (stmt); value_range *vr = NULL; bool take_default; edge e; edge_iterator ei; size_t i = 0, j = 0, n, n2; tree vec2; switch_update su; size_t k = 1, l = 0; if (TREE_CODE (op) == SSA_NAME) { vr = get_value_range (op); /* We can only handle integer ranges. */ if ((vr->type != VR_RANGE && vr->type != VR_ANTI_RANGE) || symbolic_range_p (vr)) return false; /* Find case label for min/max of the value range. */ take_default = !find_case_label_ranges (stmt, vr, &i, &j, &k, &l); } else if (TREE_CODE (op) == INTEGER_CST) { take_default = !find_case_label_index (stmt, 1, op, &i); if (take_default) { i = 1; j = 0; } else { j = i; } } else return false; n = gimple_switch_num_labels (stmt); /* We can truncate the case label ranges that partially overlap with OP's value range. */ size_t min_idx = 1, max_idx = 0; if (vr != NULL) find_case_label_range (stmt, vr->min, vr->max, &min_idx, &max_idx); if (min_idx <= max_idx) { tree min_label = gimple_switch_label (stmt, min_idx); tree max_label = gimple_switch_label (stmt, max_idx); /* Avoid changing the type of the case labels when truncating. */ tree case_label_type = TREE_TYPE (CASE_LOW (min_label)); tree vr_min = fold_convert (case_label_type, vr->min); tree vr_max = fold_convert (case_label_type, vr->max); if (vr->type == VR_RANGE) { /* If OP's value range is [2,8] and the low label range is 0 ... 3, truncate the label's range to 2 .. 3. */ if (tree_int_cst_compare (CASE_LOW (min_label), vr_min) < 0 && CASE_HIGH (min_label) != NULL_TREE && tree_int_cst_compare (CASE_HIGH (min_label), vr_min) >= 0) CASE_LOW (min_label) = vr_min; /* If OP's value range is [2,8] and the high label range is 7 ... 10, truncate the label's range to 7 .. 8. */ if (tree_int_cst_compare (CASE_LOW (max_label), vr_max) <= 0 && CASE_HIGH (max_label) != NULL_TREE && tree_int_cst_compare (CASE_HIGH (max_label), vr_max) > 0) CASE_HIGH (max_label) = vr_max; } else if (vr->type == VR_ANTI_RANGE) { tree one_cst = build_one_cst (case_label_type); if (min_label == max_label) { /* If OP's value range is ~[7,8] and the label's range is 7 ... 10, truncate the label's range to 9 ... 10. */ if (tree_int_cst_compare (CASE_LOW (min_label), vr_min) == 0 && CASE_HIGH (min_label) != NULL_TREE && tree_int_cst_compare (CASE_HIGH (min_label), vr_max) > 0) CASE_LOW (min_label) = int_const_binop (PLUS_EXPR, vr_max, one_cst); /* If OP's value range is ~[7,8] and the label's range is 5 ... 8, truncate the label's range to 5 ... 6. */ if (tree_int_cst_compare (CASE_LOW (min_label), vr_min) < 0 && CASE_HIGH (min_label) != NULL_TREE && tree_int_cst_compare (CASE_HIGH (min_label), vr_max) == 0) CASE_HIGH (min_label) = int_const_binop (MINUS_EXPR, vr_min, one_cst); } else { /* If OP's value range is ~[2,8] and the low label range is 0 ... 3, truncate the label's range to 0 ... 1. */ if (tree_int_cst_compare (CASE_LOW (min_label), vr_min) < 0 && CASE_HIGH (min_label) != NULL_TREE && tree_int_cst_compare (CASE_HIGH (min_label), vr_min) >= 0) CASE_HIGH (min_label) = int_const_binop (MINUS_EXPR, vr_min, one_cst); /* If OP's value range is ~[2,8] and the high label range is 7 ... 10, truncate the label's range to 9 ... 10. */ if (tree_int_cst_compare (CASE_LOW (max_label), vr_max) <= 0 && CASE_HIGH (max_label) != NULL_TREE && tree_int_cst_compare (CASE_HIGH (max_label), vr_max) > 0) CASE_LOW (max_label) = int_const_binop (PLUS_EXPR, vr_max, one_cst); } } /* Canonicalize singleton case ranges. */ if (tree_int_cst_equal (CASE_LOW (min_label), CASE_HIGH (min_label))) CASE_HIGH (min_label) = NULL_TREE; if (tree_int_cst_equal (CASE_LOW (max_label), CASE_HIGH (max_label))) CASE_HIGH (max_label) = NULL_TREE; } /* We can also eliminate case labels that lie completely outside OP's value range. */ /* Bail out if this is just all edges taken. */ if (i == 1 && j == n - 1 && take_default) return false; /* Build a new vector of taken case labels. */ vec2 = make_tree_vec (j - i + 1 + l - k + 1 + (int)take_default); n2 = 0; /* Add the default edge, if necessary. */ if (take_default) TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt); for (; i <= j; ++i, ++n2) TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i); for (; k <= l; ++k, ++n2) TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, k); /* Mark needed edges. */ for (i = 0; i < n2; ++i) { e = find_edge (gimple_bb (stmt), label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i)))); e->aux = (void *)-1; } /* Queue not needed edges for later removal. */ FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs) { if (e->aux == (void *)-1) { e->aux = NULL; continue; } if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "removing unreachable case label\n"); } to_remove_edges.safe_push (e); e->flags &= ~EDGE_EXECUTABLE; } /* And queue an update for the stmt. */ su.stmt = stmt; su.vec = vec2; to_update_switch_stmts.safe_push (su); return false; } /* Simplify an integral conversion from an SSA name in STMT. */ static bool simplify_conversion_using_ranges (gimple_stmt_iterator *gsi, gimple *stmt) { tree innerop, middleop, finaltype; gimple *def_stmt; signop inner_sgn, middle_sgn, final_sgn; unsigned inner_prec, middle_prec, final_prec; widest_int innermin, innermed, innermax, middlemin, middlemed, middlemax; finaltype = TREE_TYPE (gimple_assign_lhs (stmt)); if (!INTEGRAL_TYPE_P (finaltype)) return false; middleop = gimple_assign_rhs1 (stmt); def_stmt = SSA_NAME_DEF_STMT (middleop); if (!is_gimple_assign (def_stmt) || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))) return false; innerop = gimple_assign_rhs1 (def_stmt); if (TREE_CODE (innerop) != SSA_NAME || SSA_NAME_OCCURS_IN_ABNORMAL_PHI (innerop)) return false; /* Get the value-range of the inner operand. Use get_range_info in case innerop was created during substitute-and-fold. */ wide_int imin, imax; if (!INTEGRAL_TYPE_P (TREE_TYPE (innerop)) || get_range_info (innerop, &imin, &imax) != VR_RANGE) return false; innermin = widest_int::from (imin, TYPE_SIGN (TREE_TYPE (innerop))); innermax = widest_int::from (imax, TYPE_SIGN (TREE_TYPE (innerop))); /* Simulate the conversion chain to check if the result is equal if the middle conversion is removed. */ inner_prec = TYPE_PRECISION (TREE_TYPE (innerop)); middle_prec = TYPE_PRECISION (TREE_TYPE (middleop)); final_prec = TYPE_PRECISION (finaltype); /* If the first conversion is not injective, the second must not be widening. */ if (wi::gtu_p (innermax - innermin, wi::mask <widest_int> (middle_prec, false)) && middle_prec < final_prec) return false; /* We also want a medium value so that we can track the effect that narrowing conversions with sign change have. */ inner_sgn = TYPE_SIGN (TREE_TYPE (innerop)); if (inner_sgn == UNSIGNED) innermed = wi::shifted_mask <widest_int> (1, inner_prec - 1, false); else innermed = 0; if (wi::cmp (innermin, innermed, inner_sgn) >= 0 || wi::cmp (innermed, innermax, inner_sgn) >= 0) innermed = innermin; middle_sgn = TYPE_SIGN (TREE_TYPE (middleop)); middlemin = wi::ext (innermin, middle_prec, middle_sgn); middlemed = wi::ext (innermed, middle_prec, middle_sgn); middlemax = wi::ext (innermax, middle_prec, middle_sgn); /* Require that the final conversion applied to both the original and the intermediate range produces the same result. */ final_sgn = TYPE_SIGN (finaltype); if (wi::ext (middlemin, final_prec, final_sgn) != wi::ext (innermin, final_prec, final_sgn) || wi::ext (middlemed, final_prec, final_sgn) != wi::ext (innermed, final_prec, final_sgn) || wi::ext (middlemax, final_prec, final_sgn) != wi::ext (innermax, final_prec, final_sgn)) return false; gimple_assign_set_rhs1 (stmt, innerop); fold_stmt (gsi, follow_single_use_edges); return true; } /* Simplify a conversion from integral SSA name to float in STMT. */ static bool simplify_float_conversion_using_ranges (gimple_stmt_iterator *gsi, gimple *stmt) { tree rhs1 = gimple_assign_rhs1 (stmt); value_range *vr = get_value_range (rhs1); machine_mode fltmode = TYPE_MODE (TREE_TYPE (gimple_assign_lhs (stmt))); machine_mode mode; tree tem; gassign *conv; /* We can only handle constant ranges. */ if (vr->type != VR_RANGE || TREE_CODE (vr->min) != INTEGER_CST || TREE_CODE (vr->max) != INTEGER_CST) return false; /* First check if we can use a signed type in place of an unsigned. */ if (TYPE_UNSIGNED (TREE_TYPE (rhs1)) && (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)), 0) != CODE_FOR_nothing) && range_fits_type_p (vr, TYPE_PRECISION (TREE_TYPE (rhs1)), SIGNED)) mode = TYPE_MODE (TREE_TYPE (rhs1)); /* If we can do the conversion in the current input mode do nothing. */ else if (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)), TYPE_UNSIGNED (TREE_TYPE (rhs1))) != CODE_FOR_nothing) return false; /* Otherwise search for a mode we can use, starting from the narrowest integer mode available. */ else { mode = GET_CLASS_NARROWEST_MODE (MODE_INT); do { /* If we cannot do a signed conversion to float from mode or if the value-range does not fit in the signed type try with a wider mode. */ if (can_float_p (fltmode, mode, 0) != CODE_FOR_nothing && range_fits_type_p (vr, GET_MODE_PRECISION (mode), SIGNED)) break; mode = GET_MODE_WIDER_MODE (mode); /* But do not widen the input. Instead leave that to the optabs expansion code. */ if (GET_MODE_PRECISION (mode) > TYPE_PRECISION (TREE_TYPE (rhs1))) return false; } while (mode != VOIDmode); if (mode == VOIDmode) return false; } /* It works, insert a truncation or sign-change before the float conversion. */ tem = make_ssa_name (build_nonstandard_integer_type (GET_MODE_PRECISION (mode), 0)); conv = gimple_build_assign (tem, NOP_EXPR, rhs1); gsi_insert_before (gsi, conv, GSI_SAME_STMT); gimple_assign_set_rhs1 (stmt, tem); fold_stmt (gsi, follow_single_use_edges); return true; } /* Simplify an internal fn call using ranges if possible. */ static bool simplify_internal_call_using_ranges (gimple_stmt_iterator *gsi, gimple *stmt) { enum tree_code subcode; bool is_ubsan = false; bool ovf = false; switch (gimple_call_internal_fn (stmt)) { case IFN_UBSAN_CHECK_ADD: subcode = PLUS_EXPR; is_ubsan = true; break; case IFN_UBSAN_CHECK_SUB: subcode = MINUS_EXPR; is_ubsan = true; break; case IFN_UBSAN_CHECK_MUL: subcode = MULT_EXPR; is_ubsan = true; break; case IFN_ADD_OVERFLOW: subcode = PLUS_EXPR; break; case IFN_SUB_OVERFLOW: subcode = MINUS_EXPR; break; case IFN_MUL_OVERFLOW: subcode = MULT_EXPR; break; default: return false; } tree op0 = gimple_call_arg (stmt, 0); tree op1 = gimple_call_arg (stmt, 1); tree type; if (is_ubsan) { type = TREE_TYPE (op0); if (VECTOR_TYPE_P (type)) return false; } else if (gimple_call_lhs (stmt) == NULL_TREE) return false; else type = TREE_TYPE (TREE_TYPE (gimple_call_lhs (stmt))); if (!check_for_binary_op_overflow (subcode, type, op0, op1, &ovf) || (is_ubsan && ovf)) return false; gimple *g; location_t loc = gimple_location (stmt); if (is_ubsan) g = gimple_build_assign (gimple_call_lhs (stmt), subcode, op0, op1); else { int prec = TYPE_PRECISION (type); tree utype = type; if (ovf || !useless_type_conversion_p (type, TREE_TYPE (op0)) || !useless_type_conversion_p (type, TREE_TYPE (op1))) utype = build_nonstandard_integer_type (prec, 1); if (TREE_CODE (op0) == INTEGER_CST) op0 = fold_convert (utype, op0); else if (!useless_type_conversion_p (utype, TREE_TYPE (op0))) { g = gimple_build_assign (make_ssa_name (utype), NOP_EXPR, op0); gimple_set_location (g, loc); gsi_insert_before (gsi, g, GSI_SAME_STMT); op0 = gimple_assign_lhs (g); } if (TREE_CODE (op1) == INTEGER_CST) op1 = fold_convert (utype, op1); else if (!useless_type_conversion_p (utype, TREE_TYPE (op1))) { g = gimple_build_assign (make_ssa_name (utype), NOP_EXPR, op1); gimple_set_location (g, loc); gsi_insert_before (gsi, g, GSI_SAME_STMT); op1 = gimple_assign_lhs (g); } g = gimple_build_assign (make_ssa_name (utype), subcode, op0, op1); gimple_set_location (g, loc); gsi_insert_before (gsi, g, GSI_SAME_STMT); if (utype != type) { g = gimple_build_assign (make_ssa_name (type), NOP_EXPR, gimple_assign_lhs (g)); gimple_set_location (g, loc); gsi_insert_before (gsi, g, GSI_SAME_STMT); } g = gimple_build_assign (gimple_call_lhs (stmt), COMPLEX_EXPR, gimple_assign_lhs (g), build_int_cst (type, ovf)); } gimple_set_location (g, loc); gsi_replace (gsi, g, false); return true; } /* Return true if VAR is a two-valued variable. Set a and b with the two-values when it is true. Return false otherwise. */ static bool two_valued_val_range_p (tree var, tree *a, tree *b) { value_range *vr = get_value_range (var); if ((vr->type != VR_RANGE && vr->type != VR_ANTI_RANGE) || TREE_CODE (vr->min) != INTEGER_CST || TREE_CODE (vr->max) != INTEGER_CST) return false; if (vr->type == VR_RANGE && wi::sub (vr->max, vr->min) == 1) { *a = vr->min; *b = vr->max; return true; } /* ~[TYPE_MIN + 1, TYPE_MAX - 1] */ if (vr->type == VR_ANTI_RANGE && wi::sub (vr->min, vrp_val_min (TREE_TYPE (var))) == 1 && wi::sub (vrp_val_max (TREE_TYPE (var)), vr->max) == 1) { *a = vrp_val_min (TREE_TYPE (var)); *b = vrp_val_max (TREE_TYPE (var)); return true; } return false; } /* Simplify STMT using ranges if possible. */ static bool simplify_stmt_using_ranges (gimple_stmt_iterator *gsi) { gimple *stmt = gsi_stmt (*gsi); if (is_gimple_assign (stmt)) { enum tree_code rhs_code = gimple_assign_rhs_code (stmt); tree rhs1 = gimple_assign_rhs1 (stmt); tree rhs2 = gimple_assign_rhs2 (stmt); tree lhs = gimple_assign_lhs (stmt); tree val1 = NULL_TREE, val2 = NULL_TREE; use_operand_p use_p; gimple *use_stmt; /* Convert: LHS = CST BINOP VAR Where VAR is two-valued and LHS is used in GIMPLE_COND only To: LHS = VAR == VAL1 ? (CST BINOP VAL1) : (CST BINOP VAL2) Also handles: LHS = VAR BINOP CST Where VAR is two-valued and LHS is used in GIMPLE_COND only To: LHS = VAR == VAL1 ? (VAL1 BINOP CST) : (VAL2 BINOP CST) */ if (TREE_CODE_CLASS (rhs_code) == tcc_binary && INTEGRAL_TYPE_P (TREE_TYPE (lhs)) && ((TREE_CODE (rhs1) == INTEGER_CST && TREE_CODE (rhs2) == SSA_NAME) || (TREE_CODE (rhs2) == INTEGER_CST && TREE_CODE (rhs1) == SSA_NAME)) && single_imm_use (lhs, &use_p, &use_stmt) && gimple_code (use_stmt) == GIMPLE_COND) { tree new_rhs1 = NULL_TREE; tree new_rhs2 = NULL_TREE; tree cmp_var = NULL_TREE; if (TREE_CODE (rhs2) == SSA_NAME && two_valued_val_range_p (rhs2, &val1, &val2)) { /* Optimize RHS1 OP [VAL1, VAL2]. */ new_rhs1 = int_const_binop (rhs_code, rhs1, val1); new_rhs2 = int_const_binop (rhs_code, rhs1, val2); cmp_var = rhs2; } else if (TREE_CODE (rhs1) == SSA_NAME && two_valued_val_range_p (rhs1, &val1, &val2)) { /* Optimize [VAL1, VAL2] OP RHS2. */ new_rhs1 = int_const_binop (rhs_code, val1, rhs2); new_rhs2 = int_const_binop (rhs_code, val2, rhs2); cmp_var = rhs1; } /* If we could not find two-vals or the optimzation is invalid as in divide by zero, new_rhs1 / new_rhs will be NULL_TREE. */ if (new_rhs1 && new_rhs2) { tree cond = build2 (EQ_EXPR, TREE_TYPE (cmp_var), cmp_var, val1); gimple_assign_set_rhs_with_ops (gsi, COND_EXPR, cond, new_rhs1, new_rhs2); update_stmt (gsi_stmt (*gsi)); fold_stmt (gsi, follow_single_use_edges); return true; } } switch (rhs_code) { case EQ_EXPR: case NE_EXPR: /* Transform EQ_EXPR, NE_EXPR into BIT_XOR_EXPR or identity if the RHS is zero or one, and the LHS are known to be boolean values. */ if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))) return simplify_truth_ops_using_ranges (gsi, stmt); break; /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR and BIT_AND_EXPR respectively if the first operand is greater than zero and the second operand is an exact power of two. Also optimize TRUNC_MOD_EXPR away if the second operand is constant and the first operand already has the right value range. */ case TRUNC_DIV_EXPR: case TRUNC_MOD_EXPR: if (TREE_CODE (rhs1) == SSA_NAME && INTEGRAL_TYPE_P (TREE_TYPE (rhs1))) return simplify_div_or_mod_using_ranges (gsi, stmt); break; /* Transform ABS (X) into X or -X as appropriate. */ case ABS_EXPR: if (TREE_CODE (rhs1) == SSA_NAME && INTEGRAL_TYPE_P (TREE_TYPE (rhs1))) return simplify_abs_using_ranges (gsi, stmt); break; case BIT_AND_EXPR: case BIT_IOR_EXPR: /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR if all the bits being cleared are already cleared or all the bits being set are already set. */ if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))) return simplify_bit_ops_using_ranges (gsi, stmt); break; CASE_CONVERT: if (TREE_CODE (rhs1) == SSA_NAME && INTEGRAL_TYPE_P (TREE_TYPE (rhs1))) return simplify_conversion_using_ranges (gsi, stmt); break; case FLOAT_EXPR: if (TREE_CODE (rhs1) == SSA_NAME && INTEGRAL_TYPE_P (TREE_TYPE (rhs1))) return simplify_float_conversion_using_ranges (gsi, stmt); break; case MIN_EXPR: case MAX_EXPR: return simplify_min_or_max_using_ranges (gsi, stmt); default: break; } } else if (gimple_code (stmt) == GIMPLE_COND) return simplify_cond_using_ranges (as_a <gcond *> (stmt)); else if (gimple_code (stmt) == GIMPLE_SWITCH) return simplify_switch_using_ranges (as_a <gswitch *> (stmt)); else if (is_gimple_call (stmt) && gimple_call_internal_p (stmt)) return simplify_internal_call_using_ranges (gsi, stmt); return false; } /* If the statement pointed by SI has a predicate whose value can be computed using the value range information computed by VRP, compute its value and return true. Otherwise, return false. */ static bool fold_predicate_in (gimple_stmt_iterator *si) { bool assignment_p = false; tree val; gimple *stmt = gsi_stmt (*si); if (is_gimple_assign (stmt) && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison) { assignment_p = true; val = vrp_evaluate_conditional (gimple_assign_rhs_code (stmt), gimple_assign_rhs1 (stmt), gimple_assign_rhs2 (stmt), stmt); } else if (gcond *cond_stmt = dyn_cast <gcond *> (stmt)) val = vrp_evaluate_conditional (gimple_cond_code (cond_stmt), gimple_cond_lhs (cond_stmt), gimple_cond_rhs (cond_stmt), stmt); else return false; if (val) { if (assignment_p) val = fold_convert (gimple_expr_type (stmt), val); if (dump_file) { fprintf (dump_file, "Folding predicate "); print_gimple_expr (dump_file, stmt, 0, 0); fprintf (dump_file, " to "); print_generic_expr (dump_file, val, 0); fprintf (dump_file, "\n"); } if (is_gimple_assign (stmt)) gimple_assign_set_rhs_from_tree (si, val); else { gcc_assert (gimple_code (stmt) == GIMPLE_COND); gcond *cond_stmt = as_a <gcond *> (stmt); if (integer_zerop (val)) gimple_cond_make_false (cond_stmt); else if (integer_onep (val)) gimple_cond_make_true (cond_stmt); else gcc_unreachable (); } return true; } return false; } /* Callback for substitute_and_fold folding the stmt at *SI. */ static bool vrp_fold_stmt (gimple_stmt_iterator *si) { if (fold_predicate_in (si)) return true; return simplify_stmt_using_ranges (si); } /* Unwindable const/copy equivalences. */ const_and_copies *equiv_stack; /* A trivial wrapper so that we can present the generic jump threading code with a simple API for simplifying statements. STMT is the statement we want to simplify, WITHIN_STMT provides the location for any overflow warnings. */ static tree simplify_stmt_for_jump_threading (gimple *stmt, gimple *within_stmt, class avail_exprs_stack *avail_exprs_stack ATTRIBUTE_UNUSED) { if (gcond *cond_stmt = dyn_cast <gcond *> (stmt)) return vrp_evaluate_conditional (gimple_cond_code (cond_stmt), gimple_cond_lhs (cond_stmt), gimple_cond_rhs (cond_stmt), within_stmt); /* We simplify a switch statement by trying to determine which case label will be taken. If we are successful then we return the corresponding CASE_LABEL_EXPR. */ if (gswitch *switch_stmt = dyn_cast <gswitch *> (stmt)) { tree op = gimple_switch_index (switch_stmt); if (TREE_CODE (op) != SSA_NAME) return NULL_TREE; value_range *vr = get_value_range (op); if ((vr->type != VR_RANGE && vr->type != VR_ANTI_RANGE) || symbolic_range_p (vr)) return NULL_TREE; if (vr->type == VR_RANGE) { size_t i, j; /* Get the range of labels that contain a part of the operand's value range. */ find_case_label_range (switch_stmt, vr->min, vr->max, &i, &j); /* Is there only one such label? */ if (i == j) { tree label = gimple_switch_label (switch_stmt, i); /* The i'th label will be taken only if the value range of the operand is entirely within the bounds of this label. */ if (CASE_HIGH (label) != NULL_TREE ? (tree_int_cst_compare (CASE_LOW (label), vr->min) <= 0 && tree_int_cst_compare (CASE_HIGH (label), vr->max) >= 0) : (tree_int_cst_equal (CASE_LOW (label), vr->min) && tree_int_cst_equal (vr->min, vr->max))) return label; } /* If there are no such labels then the default label will be taken. */ if (i > j) return gimple_switch_label (switch_stmt, 0); } if (vr->type == VR_ANTI_RANGE) { unsigned n = gimple_switch_num_labels (switch_stmt); tree min_label = gimple_switch_label (switch_stmt, 1); tree max_label = gimple_switch_label (switch_stmt, n - 1); /* The default label will be taken only if the anti-range of the operand is entirely outside the bounds of all the (non-default) case labels. */ if (tree_int_cst_compare (vr->min, CASE_LOW (min_label)) <= 0 && (CASE_HIGH (max_label) != NULL_TREE ? tree_int_cst_compare (vr->max, CASE_HIGH (max_label)) >= 0 : tree_int_cst_compare (vr->max, CASE_LOW (max_label)) >= 0)) return gimple_switch_label (switch_stmt, 0); } return NULL_TREE; } if (gassign *assign_stmt = dyn_cast <gassign *> (stmt)) { value_range new_vr = VR_INITIALIZER; tree lhs = gimple_assign_lhs (assign_stmt); if (TREE_CODE (lhs) == SSA_NAME && (INTEGRAL_TYPE_P (TREE_TYPE (lhs)) || POINTER_TYPE_P (TREE_TYPE (lhs)))) { extract_range_from_assignment (&new_vr, assign_stmt); if (range_int_cst_singleton_p (&new_vr)) return new_vr.min; } } return NULL_TREE; } /* Blocks which have more than one predecessor and more than one successor present jump threading opportunities, i.e., when the block is reached from a specific predecessor, we may be able to determine which of the outgoing edges will be traversed. When this optimization applies, we are able to avoid conditionals at runtime and we may expose secondary optimization opportunities. This routine is effectively a driver for the generic jump threading code. It basically just presents the generic code with edges that may be suitable for jump threading. Unlike DOM, we do not iterate VRP if jump threading was successful. While iterating may expose new opportunities for VRP, it is expected those opportunities would be very limited and the compile time cost to expose those opportunities would be significant. As jump threading opportunities are discovered, they are registered for later realization. */ static void identify_jump_threads (void) { basic_block bb; gcond *dummy; int i; edge e; /* Ugh. When substituting values earlier in this pass we can wipe the dominance information. So rebuild the dominator information as we need it within the jump threading code. */ calculate_dominance_info (CDI_DOMINATORS); /* We do not allow VRP information to be used for jump threading across a back edge in the CFG. Otherwise it becomes too difficult to avoid eliminating loop exit tests. Of course EDGE_DFS_BACK is not accurate at this time so we have to recompute it. */ mark_dfs_back_edges (); /* Do not thread across edges we are about to remove. Just marking them as EDGE_IGNORE will do. */ FOR_EACH_VEC_ELT (to_remove_edges, i, e) e->flags |= EDGE_IGNORE; /* Allocate our unwinder stack to unwind any temporary equivalences that might be recorded. */ equiv_stack = new const_and_copies (); /* To avoid lots of silly node creation, we create a single conditional and just modify it in-place when attempting to thread jumps. */ dummy = gimple_build_cond (EQ_EXPR, integer_zero_node, integer_zero_node, NULL, NULL); /* Walk through all the blocks finding those which present a potential jump threading opportunity. We could set this up as a dominator walker and record data during the walk, but I doubt it's worth the effort for the classes of jump threading opportunities we are trying to identify at this point in compilation. */ FOR_EACH_BB_FN (bb, cfun) { gimple *last; /* If the generic jump threading code does not find this block interesting, then there is nothing to do. */ if (! potentially_threadable_block (bb)) continue; last = last_stmt (bb); /* We're basically looking for a switch or any kind of conditional with integral or pointer type arguments. Note the type of the second argument will be the same as the first argument, so no need to check it explicitly. We also handle the case where there are no statements in the block. This come up with forwarder blocks that are not optimized away because they lead to a loop header. But we do want to thread through them as we can sometimes thread to the loop exit which is obviously profitable. */ if (!last || gimple_code (last) == GIMPLE_SWITCH || (gimple_code (last) == GIMPLE_COND && TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last))) || POINTER_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))) && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME || is_gimple_min_invariant (gimple_cond_rhs (last))))) { edge_iterator ei; /* We've got a block with multiple predecessors and multiple successors which also ends in a suitable conditional or switch statement. For each predecessor, see if we can thread it to a specific successor. */ FOR_EACH_EDGE (e, ei, bb->preds) { /* Do not thread across edges marked to ignoreor abnormal edges in the CFG. */ if (e->flags & (EDGE_IGNORE | EDGE_COMPLEX)) continue; thread_across_edge (dummy, e, true, equiv_stack, NULL, simplify_stmt_for_jump_threading); } } } /* Clear EDGE_IGNORE. */ FOR_EACH_VEC_ELT (to_remove_edges, i, e) e->flags &= ~EDGE_IGNORE; /* We do not actually update the CFG or SSA graphs at this point as ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet handle ASSERT_EXPRs gracefully. */ } /* We identified all the jump threading opportunities earlier, but could not transform the CFG at that time. This routine transforms the CFG and arranges for the dominator tree to be rebuilt if necessary. Note the SSA graph update will occur during the normal TODO processing by the pass manager. */ static void finalize_jump_threads (void) { thread_through_all_blocks (false); delete equiv_stack; } /* Free VRP lattice. */ static void vrp_free_lattice () { /* Free allocated memory. */ free (vr_value); free (vr_phi_edge_counts); bitmap_obstack_release (&vrp_equiv_obstack); vrp_value_range_pool.release (); /* So that we can distinguish between VRP data being available and not available. */ vr_value = NULL; vr_phi_edge_counts = NULL; } /* Traverse all the blocks folding conditionals with known ranges. */ static void vrp_finalize (bool warn_array_bounds_p) { size_t i; values_propagated = true; if (dump_file) { fprintf (dump_file, "\nValue ranges after VRP:\n\n"); dump_all_value_ranges (dump_file); fprintf (dump_file, "\n"); } /* Set value range to non pointer SSA_NAMEs. */ for (i = 0; i < num_vr_values; i++) if (vr_value[i]) { tree name = ssa_name (i); if (!name || (vr_value[i]->type == VR_VARYING) || (vr_value[i]->type == VR_UNDEFINED) || (TREE_CODE (vr_value[i]->min) != INTEGER_CST) || (TREE_CODE (vr_value[i]->max) != INTEGER_CST)) continue; if (POINTER_TYPE_P (TREE_TYPE (name)) && ((vr_value[i]->type == VR_RANGE && range_includes_zero_p (vr_value[i]->min, vr_value[i]->max) == 0) || (vr_value[i]->type == VR_ANTI_RANGE && range_includes_zero_p (vr_value[i]->min, vr_value[i]->max) == 1))) set_ptr_nonnull (name); else if (!POINTER_TYPE_P (TREE_TYPE (name))) set_range_info (name, vr_value[i]->type, vr_value[i]->min, vr_value[i]->max); } substitute_and_fold (op_with_constant_singleton_value_range, vrp_fold_stmt); if (warn_array_bounds && warn_array_bounds_p) check_all_array_refs (); /* We must identify jump threading opportunities before we release the datastructures built by VRP. */ identify_jump_threads (); } /* evrp_dom_walker visits the basic blocks in the dominance order and set the Value Ranges (VR) for SSA_NAMEs in the scope. Use this VR to discover more VRs. */ class evrp_dom_walker : public dom_walker { public: evrp_dom_walker () : dom_walker (CDI_DOMINATORS), stack (10) { need_eh_cleanup = BITMAP_ALLOC (NULL); } ~evrp_dom_walker () { BITMAP_FREE (need_eh_cleanup); } virtual edge before_dom_children (basic_block); virtual void after_dom_children (basic_block); void push_value_range (tree var, value_range *vr); value_range *pop_value_range (tree var); value_range *try_find_new_range (tree op, tree_code code, tree limit); /* Cond_stack holds the old VR. */ auto_vec<std::pair <tree, value_range*> > stack; bitmap need_eh_cleanup; auto_vec<gimple *> stmts_to_fixup; auto_vec<gimple *> stmts_to_remove; }; /* Find new range for OP such that (OP CODE LIMIT) is true. */ value_range * evrp_dom_walker::try_find_new_range (tree op, tree_code code, tree limit) { value_range vr = VR_INITIALIZER; value_range *old_vr = get_value_range (op); /* Discover VR when condition is true. */ extract_range_for_var_from_comparison_expr (op, code, op, limit, &vr); if (old_vr->type == VR_RANGE || old_vr->type == VR_ANTI_RANGE) vrp_intersect_ranges (&vr, old_vr); /* If we found any usable VR, set the VR to ssa_name and create a PUSH old value in the stack with the old VR. */ if (vr.type == VR_RANGE || vr.type == VR_ANTI_RANGE) { if (old_vr->type == vr.type && vrp_operand_equal_p (old_vr->min, vr.min) && vrp_operand_equal_p (old_vr->max, vr.max)) return NULL; value_range *new_vr = vrp_value_range_pool.allocate (); *new_vr = vr; return new_vr; } return NULL; } /* See if there is any new scope is entered with new VR and set that VR to ssa_name before visiting the statements in the scope. */ edge evrp_dom_walker::before_dom_children (basic_block bb) { tree op0 = NULL_TREE; edge_iterator ei; edge e; if (dump_file && (dump_flags & TDF_DETAILS)) fprintf (dump_file, "Visiting BB%d\n", bb->index); stack.safe_push (std::make_pair (NULL_TREE, (value_range *)NULL)); edge pred_e = NULL; FOR_EACH_EDGE (e, ei, bb->preds) { /* Ignore simple backedges from this to allow recording conditions in loop headers. */ if (dominated_by_p (CDI_DOMINATORS, e->src, e->dest)) continue; if (! pred_e) pred_e = e; else { pred_e = NULL; break; } } if (pred_e) { gimple *stmt = last_stmt (pred_e->src); if (stmt && gimple_code (stmt) == GIMPLE_COND && (op0 = gimple_cond_lhs (stmt)) && TREE_CODE (op0) == SSA_NAME && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt))) || POINTER_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt))))) { if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "Visiting controlling predicate "); print_gimple_stmt (dump_file, stmt, 0, 0); } /* Entering a new scope. Try to see if we can find a VR here. */ tree op1 = gimple_cond_rhs (stmt); tree_code code = gimple_cond_code (stmt); if (TREE_OVERFLOW_P (op1)) op1 = drop_tree_overflow (op1); /* If condition is false, invert the cond. */ if (pred_e->flags & EDGE_FALSE_VALUE) code = invert_tree_comparison (gimple_cond_code (stmt), HONOR_NANS (op0)); /* Add VR when (OP0 CODE OP1) condition is true. */ value_range *op0_range = try_find_new_range (op0, code, op1); /* Register ranges for y in x < y where y might have ranges that are useful. */ tree limit; tree_code new_code; if (TREE_CODE (op1) == SSA_NAME && extract_code_and_val_from_cond_with_ops (op1, code, op0, op1, false, &new_code, &limit)) { /* Add VR when (OP1 NEW_CODE LIMIT) condition is true. */ value_range *op1_range = try_find_new_range (op1, new_code, limit); if (op1_range) push_value_range (op1, op1_range); } if (op0_range) push_value_range (op0, op0_range); } } /* Visit PHI stmts and discover any new VRs possible. */ bool has_unvisited_preds = false; FOR_EACH_EDGE (e, ei, bb->preds) if (e->flags & EDGE_EXECUTABLE && !(e->src->flags & BB_VISITED)) { has_unvisited_preds = true; break; } for (gphi_iterator gpi = gsi_start_phis (bb); !gsi_end_p (gpi); gsi_next (&gpi)) { gphi *phi = gpi.phi (); tree lhs = PHI_RESULT (phi); if (virtual_operand_p (lhs)) continue; value_range vr_result = VR_INITIALIZER; bool interesting = stmt_interesting_for_vrp (phi); if (interesting && dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "Visiting PHI node "); print_gimple_stmt (dump_file, phi, 0, 0); } if (!has_unvisited_preds && interesting) extract_range_from_phi_node (phi, &vr_result); else { set_value_range_to_varying (&vr_result); /* When we have an unvisited executable predecessor we can't use PHI arg ranges which may be still UNDEFINED but have to use VARYING for them. But we can still resort to SCEV for loop header PHIs. */ struct loop *l; if (interesting && (l = loop_containing_stmt (phi)) && l->header == gimple_bb (phi)) adjust_range_with_scev (&vr_result, l, phi, lhs); } update_value_range (lhs, &vr_result); /* Mark PHIs whose lhs we fully propagate for removal. */ tree val = op_with_constant_singleton_value_range (lhs); if (val && may_propagate_copy (lhs, val)) stmts_to_remove.safe_push (phi); } edge taken_edge = NULL; /* Visit all other stmts and discover any new VRs possible. */ for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) { gimple *stmt = gsi_stmt (gsi); tree output = NULL_TREE; gimple *old_stmt = stmt; bool was_noreturn = (is_gimple_call (stmt) && gimple_call_noreturn_p (stmt)); if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "Visiting stmt "); print_gimple_stmt (dump_file, stmt, 0, 0); } if (gcond *cond = dyn_cast <gcond *> (stmt)) { vrp_visit_cond_stmt (cond, &taken_edge); if (taken_edge) { if (taken_edge->flags & EDGE_TRUE_VALUE) gimple_cond_make_true (cond); else if (taken_edge->flags & EDGE_FALSE_VALUE) gimple_cond_make_false (cond); else gcc_unreachable (); update_stmt (stmt); } } else if (stmt_interesting_for_vrp (stmt)) { edge taken_edge; value_range vr = VR_INITIALIZER; extract_range_from_stmt (stmt, &taken_edge, &output, &vr); if (output && (vr.type == VR_RANGE || vr.type == VR_ANTI_RANGE)) { update_value_range (output, &vr); vr = *get_value_range (output); /* Set the SSA with the value range. */ if (INTEGRAL_TYPE_P (TREE_TYPE (output))) { if ((vr.type == VR_RANGE || vr.type == VR_ANTI_RANGE) && (TREE_CODE (vr.min) == INTEGER_CST) && (TREE_CODE (vr.max) == INTEGER_CST)) set_range_info (output, vr.type, vr.min, vr.max); } else if (POINTER_TYPE_P (TREE_TYPE (output)) && ((vr.type == VR_RANGE && range_includes_zero_p (vr.min, vr.max) == 0) || (vr.type == VR_ANTI_RANGE && range_includes_zero_p (vr.min, vr.max) == 1))) set_ptr_nonnull (output); /* Mark stmts whose output we fully propagate for removal. */ tree val; if ((val = op_with_constant_singleton_value_range (output)) && may_propagate_copy (output, val) && !stmt_could_throw_p (stmt) && !gimple_has_side_effects (stmt)) { stmts_to_remove.safe_push (stmt); continue; } } else set_defs_to_varying (stmt); } else set_defs_to_varying (stmt); /* See if we can derive a range for any of STMT's operands. */ tree op; ssa_op_iter i; FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE) { tree value; enum tree_code comp_code; /* If OP is used in such a way that we can infer a value range for it, and we don't find a previous assertion for it, create a new assertion location node for OP. */ if (infer_value_range (stmt, op, &comp_code, &value)) { /* If we are able to infer a nonzero value range for OP, then walk backwards through the use-def chain to see if OP was set via a typecast. If so, then we can also infer a nonzero value range for the operand of the NOP_EXPR. */ if (comp_code == NE_EXPR && integer_zerop (value)) { tree t = op; gimple *def_stmt = SSA_NAME_DEF_STMT (t); while (is_gimple_assign (def_stmt) && CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)) && TREE_CODE (gimple_assign_rhs1 (def_stmt)) == SSA_NAME && POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))) { t = gimple_assign_rhs1 (def_stmt); def_stmt = SSA_NAME_DEF_STMT (t); /* Add VR when (T COMP_CODE value) condition is true. */ value_range *op_range = try_find_new_range (t, comp_code, value); if (op_range) push_value_range (t, op_range); } } /* Add VR when (OP COMP_CODE value) condition is true. */ value_range *op_range = try_find_new_range (op, comp_code, value); if (op_range) push_value_range (op, op_range); } } /* Try folding stmts with the VR discovered. */ bool did_replace = replace_uses_in (stmt, op_with_constant_singleton_value_range); if (fold_stmt (&gsi, follow_single_use_edges) || did_replace) { stmt = gsi_stmt (gsi); update_stmt (stmt); did_replace = true; } if (did_replace) { /* If we cleaned up EH information from the statement, remove EH edges. */ if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt)) bitmap_set_bit (need_eh_cleanup, bb->index); /* If we turned a not noreturn call into a noreturn one schedule it for fixup. */ if (!was_noreturn && is_gimple_call (stmt) && gimple_call_noreturn_p (stmt)) stmts_to_fixup.safe_push (stmt); if (gimple_assign_single_p (stmt)) { tree rhs = gimple_assign_rhs1 (stmt); if (TREE_CODE (rhs) == ADDR_EXPR) recompute_tree_invariant_for_addr_expr (rhs); } } } /* Visit BB successor PHI nodes and replace PHI args. */ FOR_EACH_EDGE (e, ei, bb->succs) { for (gphi_iterator gpi = gsi_start_phis (e->dest); !gsi_end_p (gpi); gsi_next (&gpi)) { gphi *phi = gpi.phi (); use_operand_p use_p = PHI_ARG_DEF_PTR_FROM_EDGE (phi, e); tree arg = USE_FROM_PTR (use_p); if (TREE_CODE (arg) != SSA_NAME || virtual_operand_p (arg)) continue; tree val = op_with_constant_singleton_value_range (arg); if (val && may_propagate_copy (arg, val)) propagate_value (use_p, val); } } bb->flags |= BB_VISITED; return taken_edge; } /* Restore/pop VRs valid only for BB when we leave BB. */ void evrp_dom_walker::after_dom_children (basic_block bb ATTRIBUTE_UNUSED) { gcc_checking_assert (!stack.is_empty ()); while (stack.last ().first != NULL_TREE) pop_value_range (stack.last ().first); stack.pop (); } /* Push the Value Range of VAR to the stack and update it with new VR. */ void evrp_dom_walker::push_value_range (tree var, value_range *vr) { if (SSA_NAME_VERSION (var) >= num_vr_values) return; if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "pushing new range for "); print_generic_expr (dump_file, var, 0); fprintf (dump_file, ": "); dump_value_range (dump_file, vr); fprintf (dump_file, "\n"); } stack.safe_push (std::make_pair (var, get_value_range (var))); vr_value[SSA_NAME_VERSION (var)] = vr; } /* Pop the Value Range from the vrp_stack and update VAR with it. */ value_range * evrp_dom_walker::pop_value_range (tree var) { value_range *vr = stack.last ().second; gcc_checking_assert (var == stack.last ().first); if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "popping range for "); print_generic_expr (dump_file, var, 0); fprintf (dump_file, ", restoring "); dump_value_range (dump_file, vr); fprintf (dump_file, "\n"); } vr_value[SSA_NAME_VERSION (var)] = vr; stack.pop (); return vr; } /* Main entry point for the early vrp pass which is a simplified non-iterative version of vrp where basic blocks are visited in dominance order. Value ranges discovered in early vrp will also be used by ipa-vrp. */ static unsigned int execute_early_vrp () { edge e; edge_iterator ei; basic_block bb; loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS); rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa); scev_initialize (); calculate_dominance_info (CDI_DOMINATORS); FOR_EACH_BB_FN (bb, cfun) { bb->flags &= ~BB_VISITED; FOR_EACH_EDGE (e, ei, bb->preds) e->flags |= EDGE_EXECUTABLE; } vrp_initialize_lattice (); /* Walk stmts in dominance order and propagate VRP. */ evrp_dom_walker walker; walker.walk (ENTRY_BLOCK_PTR_FOR_FN (cfun)); if (dump_file) { fprintf (dump_file, "\nValue ranges after Early VRP:\n\n"); dump_all_value_ranges (dump_file); fprintf (dump_file, "\n"); } /* Remove stmts in reverse order to make debug stmt creation possible. */ while (! walker.stmts_to_remove.is_empty ()) { gimple *stmt = walker.stmts_to_remove.pop (); if (dump_file && dump_flags & TDF_DETAILS) { fprintf (dump_file, "Removing dead stmt "); print_gimple_stmt (dump_file, stmt, 0, 0); fprintf (dump_file, "\n"); } gimple_stmt_iterator gsi = gsi_for_stmt (stmt); if (gimple_code (stmt) == GIMPLE_PHI) remove_phi_node (&gsi, true); else { unlink_stmt_vdef (stmt); gsi_remove (&gsi, true); release_defs (stmt); } } if (!bitmap_empty_p (walker.need_eh_cleanup)) gimple_purge_all_dead_eh_edges (walker.need_eh_cleanup); /* Fixup stmts that became noreturn calls. This may require splitting blocks and thus isn't possible during the dominator walk. Do this in reverse order so we don't inadvertedly remove a stmt we want to fixup by visiting a dominating now noreturn call first. */ while (!walker.stmts_to_fixup.is_empty ()) { gimple *stmt = walker.stmts_to_fixup.pop (); fixup_noreturn_call (stmt); } vrp_free_lattice (); scev_finalize (); loop_optimizer_finalize (); return 0; } /* Main entry point to VRP (Value Range Propagation). This pass is loosely based on J. R. C. Patterson, ``Accurate Static Branch Prediction by Value Range Propagation,'' in SIGPLAN Conference on Programming Language Design and Implementation, pp. 67-78, 1995. Also available at http://citeseer.ist.psu.edu/patterson95accurate.html This is essentially an SSA-CCP pass modified to deal with ranges instead of constants. While propagating ranges, we may find that two or more SSA name have equivalent, though distinct ranges. For instance, 1 x_9 = p_3->a; 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0> 3 if (p_4 == q_2) 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>; 5 endif 6 if (q_2) In the code above, pointer p_5 has range [q_2, q_2], but from the code we can also determine that p_5 cannot be NULL and, if q_2 had a non-varying range, p_5's range should also be compatible with it. These equivalences are created by two expressions: ASSERT_EXPR and copy operations. Since p_5 is an assertion on p_4, and p_4 was the result of another assertion, then we can use the fact that p_5 and p_4 are equivalent when evaluating p_5's range. Together with value ranges, we also propagate these equivalences between names so that we can take advantage of information from multiple ranges when doing final replacement. Note that this equivalency relation is transitive but not symmetric. In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we cannot assert that q_2 is equivalent to p_5 because q_2 may be used in contexts where that assertion does not hold (e.g., in line 6). TODO, the main difference between this pass and Patterson's is that we do not propagate edge probabilities. We only compute whether edges can be taken or not. That is, instead of having a spectrum of jump probabilities between 0 and 1, we only deal with 0, 1 and DON'T KNOW. In the future, it may be worthwhile to propagate probabilities to aid branch prediction. */ static unsigned int execute_vrp (bool warn_array_bounds_p) { int i; edge e; switch_update *su; loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS); rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa); scev_initialize (); /* ??? This ends up using stale EDGE_DFS_BACK for liveness computation. Inserting assertions may split edges which will invalidate EDGE_DFS_BACK. */ insert_range_assertions (); to_remove_edges.create (10); to_update_switch_stmts.create (5); threadedge_initialize_values (); /* For visiting PHI nodes we need EDGE_DFS_BACK computed. */ mark_dfs_back_edges (); vrp_initialize_lattice (); vrp_initialize (); ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node); vrp_finalize (warn_array_bounds_p); vrp_free_lattice (); free_numbers_of_iterations_estimates (cfun); /* ASSERT_EXPRs must be removed before finalizing jump threads as finalizing jump threads calls the CFG cleanup code which does not properly handle ASSERT_EXPRs. */ remove_range_assertions (); /* If we exposed any new variables, go ahead and put them into SSA form now, before we handle jump threading. This simplifies interactions between rewriting of _DECL nodes into SSA form and rewriting SSA_NAME nodes into SSA form after block duplication and CFG manipulation. */ update_ssa (TODO_update_ssa); finalize_jump_threads (); /* Remove dead edges from SWITCH_EXPR optimization. This leaves the CFG in a broken state and requires a cfg_cleanup run. */ FOR_EACH_VEC_ELT (to_remove_edges, i, e) remove_edge (e); /* Update SWITCH_EXPR case label vector. */ FOR_EACH_VEC_ELT (to_update_switch_stmts, i, su) { size_t j; size_t n = TREE_VEC_LENGTH (su->vec); tree label; gimple_switch_set_num_labels (su->stmt, n); for (j = 0; j < n; j++) gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j)); /* As we may have replaced the default label with a regular one make sure to make it a real default label again. This ensures optimal expansion. */ label = gimple_switch_label (su->stmt, 0); CASE_LOW (label) = NULL_TREE; CASE_HIGH (label) = NULL_TREE; } if (to_remove_edges.length () > 0) { free_dominance_info (CDI_DOMINATORS); loops_state_set (LOOPS_NEED_FIXUP); } to_remove_edges.release (); to_update_switch_stmts.release (); threadedge_finalize_values (); scev_finalize (); loop_optimizer_finalize (); return 0; } namespace { const pass_data pass_data_vrp = { GIMPLE_PASS, /* type */ "vrp", /* name */ OPTGROUP_NONE, /* optinfo_flags */ TV_TREE_VRP, /* tv_id */ PROP_ssa, /* properties_required */ 0, /* properties_provided */ 0, /* properties_destroyed */ 0, /* todo_flags_start */ ( TODO_cleanup_cfg | TODO_update_ssa ), /* todo_flags_finish */ }; class pass_vrp : public gimple_opt_pass { public: pass_vrp (gcc::context *ctxt) : gimple_opt_pass (pass_data_vrp, ctxt), warn_array_bounds_p (false) {} /* opt_pass methods: */ opt_pass * clone () { return new pass_vrp (m_ctxt); } void set_pass_param (unsigned int n, bool param) { gcc_assert (n == 0); warn_array_bounds_p = param; } virtual bool gate (function *) { return flag_tree_vrp != 0; } virtual unsigned int execute (function *) { return execute_vrp (warn_array_bounds_p); } private: bool warn_array_bounds_p; }; // class pass_vrp } // anon namespace gimple_opt_pass * make_pass_vrp (gcc::context *ctxt) { return new pass_vrp (ctxt); } namespace { const pass_data pass_data_early_vrp = { GIMPLE_PASS, /* type */ "evrp", /* name */ OPTGROUP_NONE, /* optinfo_flags */ TV_TREE_EARLY_VRP, /* tv_id */ PROP_ssa, /* properties_required */ 0, /* properties_provided */ 0, /* properties_destroyed */ 0, /* todo_flags_start */ ( TODO_cleanup_cfg | TODO_update_ssa | TODO_verify_all ), }; class pass_early_vrp : public gimple_opt_pass { public: pass_early_vrp (gcc::context *ctxt) : gimple_opt_pass (pass_data_early_vrp, ctxt) {} /* opt_pass methods: */ opt_pass * clone () { return new pass_early_vrp (m_ctxt); } virtual bool gate (function *) { return flag_tree_vrp != 0; } virtual unsigned int execute (function *) { return execute_early_vrp (); } }; // class pass_vrp } // anon namespace gimple_opt_pass * make_pass_early_vrp (gcc::context *ctxt) { return new pass_early_vrp (ctxt); }