/* Memory address lowering and addressing mode selection. Copyright (C) 2004, 2006 Free Software Foundation, Inc. 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 2, 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 COPYING. If not, write to the Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ /* Utility functions for manipulation with TARGET_MEM_REFs -- tree expressions that directly map to addressing modes of the target. */ #include "config.h" #include "system.h" #include "coretypes.h" #include "tm.h" #include "tree.h" #include "rtl.h" #include "tm_p.h" #include "hard-reg-set.h" #include "basic-block.h" #include "output.h" #include "diagnostic.h" #include "tree-flow.h" #include "tree-dump.h" #include "tree-pass.h" #include "timevar.h" #include "flags.h" #include "tree-inline.h" #include "insn-config.h" #include "recog.h" #include "expr.h" #include "ggc.h" #include "tree-affine.h" /* TODO -- handling of symbols (according to Richard Hendersons comments, http://gcc.gnu.org/ml/gcc-patches/2005-04/msg00949.html): There are at least 5 different kinds of symbols that we can run up against: (1) binds_local_p, small data area. (2) binds_local_p, eg local statics (3) !binds_local_p, eg global variables (4) thread local, local_exec (5) thread local, !local_exec Now, (1) won't appear often in an array context, but it certainly can. All you have to do is set -GN high enough, or explicitly mark any random object __attribute__((section (".sdata"))). All of these affect whether or not a symbol is in fact a valid address. The only one tested here is (3). And that result may very well be incorrect for (4) or (5). An incorrect result here does not cause incorrect results out the back end, because the expander in expr.c validizes the address. However it would be nice to improve the handling here in order to produce more precise results. */ /* A "template" for memory address, used to determine whether the address is valid for mode. */ struct mem_addr_template GTY (()) { rtx ref; /* The template. */ rtx * GTY ((skip)) step_p; /* The point in template where the step should be filled in. */ rtx * GTY ((skip)) off_p; /* The point in template where the offset should be filled in. */ }; /* The templates. Each of the five bits of the index corresponds to one component of TARGET_MEM_REF being present, see TEMPL_IDX. */ static GTY (()) struct mem_addr_template templates[32]; #define TEMPL_IDX(SYMBOL, BASE, INDEX, STEP, OFFSET) \ (((SYMBOL != 0) << 4) \ | ((BASE != 0) << 3) \ | ((INDEX != 0) << 2) \ | ((STEP != 0) << 1) \ | (OFFSET != 0)) /* Stores address for memory reference with parameters SYMBOL, BASE, INDEX, STEP and OFFSET to *ADDR. Stores pointers to where step is placed to *STEP_P and offset to *OFFSET_P. */ static void gen_addr_rtx (rtx symbol, rtx base, rtx index, rtx step, rtx offset, rtx *addr, rtx **step_p, rtx **offset_p) { rtx act_elem; *addr = NULL_RTX; if (step_p) *step_p = NULL; if (offset_p) *offset_p = NULL; if (index) { act_elem = index; if (step) { act_elem = gen_rtx_MULT (Pmode, act_elem, step); if (step_p) *step_p = &XEXP (act_elem, 1); } *addr = act_elem; } if (base) { if (*addr) *addr = gen_rtx_PLUS (Pmode, *addr, base); else *addr = base; } if (symbol) { act_elem = symbol; if (offset) { act_elem = gen_rtx_PLUS (Pmode, act_elem, offset); if (offset_p) *offset_p = &XEXP (act_elem, 1); if (GET_CODE (symbol) == SYMBOL_REF || GET_CODE (symbol) == LABEL_REF || GET_CODE (symbol) == CONST) act_elem = gen_rtx_CONST (Pmode, act_elem); } if (*addr) *addr = gen_rtx_PLUS (Pmode, *addr, act_elem); else *addr = act_elem; } else if (offset) { if (*addr) { *addr = gen_rtx_PLUS (Pmode, *addr, offset); if (offset_p) *offset_p = &XEXP (*addr, 1); } else { *addr = offset; if (offset_p) *offset_p = addr; } } if (!*addr) *addr = const0_rtx; } /* Returns address for TARGET_MEM_REF with parameters given by ADDR. If REALLY_EXPAND is false, just make fake registers instead of really expanding the operands, and perform the expansion in-place by using one of the "templates". */ rtx addr_for_mem_ref (struct mem_address *addr, bool really_expand) { rtx address, sym, bse, idx, st, off; static bool templates_initialized = false; struct mem_addr_template *templ; if (addr->step && !integer_onep (addr->step)) st = immed_double_const (TREE_INT_CST_LOW (addr->step), TREE_INT_CST_HIGH (addr->step), Pmode); else st = NULL_RTX; if (addr->offset && !integer_zerop (addr->offset)) off = immed_double_const (TREE_INT_CST_LOW (addr->offset), TREE_INT_CST_HIGH (addr->offset), Pmode); else off = NULL_RTX; if (!really_expand) { /* Reuse the templates for addresses, so that we do not waste memory. */ if (!templates_initialized) { unsigned i; templates_initialized = true; sym = gen_rtx_SYMBOL_REF (Pmode, ggc_strdup ("test_symbol")); bse = gen_raw_REG (Pmode, LAST_VIRTUAL_REGISTER + 1); idx = gen_raw_REG (Pmode, LAST_VIRTUAL_REGISTER + 2); for (i = 0; i < 32; i++) gen_addr_rtx ((i & 16 ? sym : NULL_RTX), (i & 8 ? bse : NULL_RTX), (i & 4 ? idx : NULL_RTX), (i & 2 ? const0_rtx : NULL_RTX), (i & 1 ? const0_rtx : NULL_RTX), &templates[i].ref, &templates[i].step_p, &templates[i].off_p); } templ = templates + TEMPL_IDX (addr->symbol, addr->base, addr->index, st, off); if (st) *templ->step_p = st; if (off) *templ->off_p = off; return templ->ref; } /* Otherwise really expand the expressions. */ sym = (addr->symbol ? expand_expr (build_addr (addr->symbol, current_function_decl), NULL_RTX, Pmode, EXPAND_NORMAL) : NULL_RTX); bse = (addr->base ? expand_expr (addr->base, NULL_RTX, Pmode, EXPAND_NORMAL) : NULL_RTX); idx = (addr->index ? expand_expr (addr->index, NULL_RTX, Pmode, EXPAND_NORMAL) : NULL_RTX); gen_addr_rtx (sym, bse, idx, st, off, &address, NULL, NULL); return address; } /* Returns address of MEM_REF in TYPE. */ tree tree_mem_ref_addr (tree type, tree mem_ref) { tree addr; tree act_elem; tree step = TMR_STEP (mem_ref), offset = TMR_OFFSET (mem_ref); tree sym = TMR_SYMBOL (mem_ref), base = TMR_BASE (mem_ref); tree addr_base = NULL_TREE, addr_off = NULL_TREE; if (sym) addr_base = fold_convert (type, build_addr (sym, current_function_decl)); else if (base && POINTER_TYPE_P (TREE_TYPE (base))) { addr_base = fold_convert (type, base); base = NULL_TREE; } act_elem = TMR_INDEX (mem_ref); if (act_elem) { if (step) act_elem = fold_build2 (MULT_EXPR, sizetype, act_elem, step); addr_off = act_elem; } act_elem = base; if (act_elem) { if (addr_off) addr_off = fold_build2 (PLUS_EXPR, sizetype, addr_off, act_elem); else addr_off = act_elem; } if (offset && !integer_zerop (offset)) { if (addr_off) addr_off = fold_build2 (PLUS_EXPR, sizetype, addr_off, offset); else addr_off = offset; } if (addr_off) { if (addr_base) addr = fold_build2 (POINTER_PLUS_EXPR, type, addr_base, addr_off); else addr = fold_convert (type, addr_off); } else if (addr_base) addr = addr_base; else addr = build_int_cst (type, 0); return addr; } /* Returns true if a memory reference in MODE and with parameters given by ADDR is valid on the current target. */ static bool valid_mem_ref_p (enum machine_mode mode, struct mem_address *addr) { rtx address; address = addr_for_mem_ref (addr, false); if (!address) return false; return memory_address_p (mode, address); } /* Checks whether a TARGET_MEM_REF with type TYPE and parameters given by ADDR is valid on the current target and if so, creates and returns the TARGET_MEM_REF. */ static tree create_mem_ref_raw (tree type, struct mem_address *addr) { if (!valid_mem_ref_p (TYPE_MODE (type), addr)) return NULL_TREE; if (addr->step && integer_onep (addr->step)) addr->step = NULL_TREE; if (addr->offset && integer_zerop (addr->offset)) addr->offset = NULL_TREE; return build7 (TARGET_MEM_REF, type, addr->symbol, addr->base, addr->index, addr->step, addr->offset, NULL, NULL); } /* Returns true if OBJ is an object whose address is a link time constant. */ static bool fixed_address_object_p (tree obj) { return (TREE_CODE (obj) == VAR_DECL && (TREE_STATIC (obj) || DECL_EXTERNAL (obj))); } /* If ADDR contains an address of object that is a link time constant, move it to PARTS->symbol. */ static void move_fixed_address_to_symbol (struct mem_address *parts, aff_tree *addr) { unsigned i; tree val = NULL_TREE; for (i = 0; i < addr->n; i++) { if (!double_int_one_p (addr->elts[i].coef)) continue; val = addr->elts[i].val; if (TREE_CODE (val) == ADDR_EXPR && fixed_address_object_p (TREE_OPERAND (val, 0))) break; } if (i == addr->n) return; parts->symbol = TREE_OPERAND (val, 0); aff_combination_remove_elt (addr, i); } /* If ADDR contains an address of a dereferenced pointer, move it to PARTS->base. */ static void move_pointer_to_base (struct mem_address *parts, aff_tree *addr) { unsigned i; tree val = NULL_TREE; for (i = 0; i < addr->n; i++) { if (!double_int_one_p (addr->elts[i].coef)) continue; val = addr->elts[i].val; if (POINTER_TYPE_P (TREE_TYPE (val))) break; } if (i == addr->n) return; parts->base = val; aff_combination_remove_elt (addr, i); } /* Adds ELT to PARTS. */ static void add_to_parts (struct mem_address *parts, tree elt) { tree type; if (!parts->index) { parts->index = fold_convert (sizetype, elt); return; } if (!parts->base) { parts->base = elt; return; } /* Add ELT to base. */ type = TREE_TYPE (parts->base); parts->base = fold_build2 (PLUS_EXPR, type, parts->base, fold_convert (type, elt)); } /* Finds the most expensive multiplication in ADDR that can be expressed in an addressing mode and move the corresponding element(s) to PARTS. */ static void most_expensive_mult_to_index (struct mem_address *parts, aff_tree *addr) { HOST_WIDE_INT coef; double_int best_mult, amult, amult_neg; unsigned best_mult_cost = 0, acost; tree mult_elt = NULL_TREE, elt; unsigned i, j; enum tree_code op_code; best_mult = double_int_zero; for (i = 0; i < addr->n; i++) { if (!double_int_fits_in_shwi_p (addr->elts[i].coef)) continue; /* FIXME: Should use the correct memory mode rather than Pmode. */ coef = double_int_to_shwi (addr->elts[i].coef); if (coef == 1 || !multiplier_allowed_in_address_p (coef, Pmode)) continue; acost = multiply_by_cost (coef, Pmode); if (acost > best_mult_cost) { best_mult_cost = acost; best_mult = addr->elts[i].coef; } } if (!best_mult_cost) return; /* Collect elements multiplied by best_mult. */ for (i = j = 0; i < addr->n; i++) { amult = addr->elts[i].coef; amult_neg = double_int_ext_for_comb (double_int_neg (amult), addr); if (double_int_equal_p (amult, best_mult)) op_code = PLUS_EXPR; else if (double_int_equal_p (amult_neg, best_mult)) op_code = MINUS_EXPR; else { addr->elts[j] = addr->elts[i]; j++; continue; } elt = fold_convert (sizetype, addr->elts[i].val); if (mult_elt) mult_elt = fold_build2 (op_code, sizetype, mult_elt, elt); else if (op_code == PLUS_EXPR) mult_elt = elt; else mult_elt = fold_build1 (NEGATE_EXPR, sizetype, elt); } addr->n = j; parts->index = mult_elt; parts->step = double_int_to_tree (sizetype, best_mult); } /* Splits address ADDR into PARTS. TODO -- be more clever about the distribution of the elements of ADDR to PARTS. Some architectures do not support anything but single register in address, possibly with a small integer offset; while create_mem_ref will simplify the address to an acceptable shape later, it would be more efficient to know that asking for complicated addressing modes is useless. */ static void addr_to_parts (aff_tree *addr, struct mem_address *parts) { tree part; unsigned i; parts->symbol = NULL_TREE; parts->base = NULL_TREE; parts->index = NULL_TREE; parts->step = NULL_TREE; if (!double_int_zero_p (addr->offset)) parts->offset = double_int_to_tree (sizetype, addr->offset); else parts->offset = NULL_TREE; /* Try to find a symbol. */ move_fixed_address_to_symbol (parts, addr); /* First move the most expensive feasible multiplication to index. */ most_expensive_mult_to_index (parts, addr); /* Try to find a base of the reference. Since at the moment there is no reliable way how to distinguish between pointer and its offset, this is just a guess. */ if (!parts->symbol) move_pointer_to_base (parts, addr); /* Then try to process the remaining elements. */ for (i = 0; i < addr->n; i++) { part = fold_convert (sizetype, addr->elts[i].val); if (!double_int_one_p (addr->elts[i].coef)) part = fold_build2 (MULT_EXPR, sizetype, part, double_int_to_tree (sizetype, addr->elts[i].coef)); add_to_parts (parts, part); } if (addr->rest) add_to_parts (parts, fold_convert (sizetype, addr->rest)); } /* Force the PARTS to register. */ static void gimplify_mem_ref_parts (block_stmt_iterator *bsi, struct mem_address *parts) { if (parts->base) parts->base = force_gimple_operand_bsi (bsi, parts->base, true, NULL_TREE); if (parts->index) parts->index = force_gimple_operand_bsi (bsi, parts->index, true, NULL_TREE); } /* Creates and returns a TARGET_MEM_REF for address ADDR. If necessary computations are emitted in front of BSI. TYPE is the mode of created memory reference. */ tree create_mem_ref (block_stmt_iterator *bsi, tree type, aff_tree *addr) { tree mem_ref, tmp; tree atype; struct mem_address parts; addr_to_parts (addr, &parts); gimplify_mem_ref_parts (bsi, &parts); mem_ref = create_mem_ref_raw (type, &parts); if (mem_ref) return mem_ref; /* The expression is too complicated. Try making it simpler. */ if (parts.step && !integer_onep (parts.step)) { /* Move the multiplication to index. */ gcc_assert (parts.index); parts.index = force_gimple_operand_bsi (bsi, fold_build2 (MULT_EXPR, sizetype, parts.index, parts.step), true, NULL_TREE); parts.step = NULL_TREE; mem_ref = create_mem_ref_raw (type, &parts); if (mem_ref) return mem_ref; } if (parts.symbol) { tmp = build_addr (parts.symbol, current_function_decl); gcc_assert (is_gimple_val (tmp)); /* Add the symbol to base, eventually forcing it to register. */ if (parts.base) { gcc_assert (useless_type_conversion_p (sizetype, TREE_TYPE (parts.base))); if (parts.index) { atype = TREE_TYPE (tmp); parts.base = force_gimple_operand_bsi (bsi, fold_build2 (PLUS_EXPR, atype, fold_convert (atype, parts.base), tmp), true, NULL_TREE); } else { parts.index = parts.base; parts.base = tmp; } } else parts.base = tmp; parts.symbol = NULL_TREE; mem_ref = create_mem_ref_raw (type, &parts); if (mem_ref) return mem_ref; } if (parts.index) { /* Add index to base. */ if (parts.base) { atype = TREE_TYPE (parts.base); parts.base = force_gimple_operand_bsi (bsi, fold_build2 (PLUS_EXPR, atype, parts.base, fold_convert (atype, parts.index)), true, NULL_TREE); } else parts.base = parts.index; parts.index = NULL_TREE; mem_ref = create_mem_ref_raw (type, &parts); if (mem_ref) return mem_ref; } if (parts.offset && !integer_zerop (parts.offset)) { /* Try adding offset to base. */ if (parts.base) { atype = TREE_TYPE (parts.base); parts.base = force_gimple_operand_bsi (bsi, fold_build2 (POINTER_PLUS_EXPR, atype, parts.base, fold_convert (sizetype, parts.offset)), true, NULL_TREE); } else parts.base = parts.offset; parts.offset = NULL_TREE; mem_ref = create_mem_ref_raw (type, &parts); if (mem_ref) return mem_ref; } /* Verify that the address is in the simplest possible shape (only a register). If we cannot create such a memory reference, something is really wrong. */ gcc_assert (parts.symbol == NULL_TREE); gcc_assert (parts.index == NULL_TREE); gcc_assert (!parts.step || integer_onep (parts.step)); gcc_assert (!parts.offset || integer_zerop (parts.offset)); gcc_unreachable (); } /* Copies components of the address from OP to ADDR. */ void get_address_description (tree op, struct mem_address *addr) { addr->symbol = TMR_SYMBOL (op); addr->base = TMR_BASE (op); addr->index = TMR_INDEX (op); addr->step = TMR_STEP (op); addr->offset = TMR_OFFSET (op); } /* Copies the additional information attached to target_mem_ref FROM to TO. */ void copy_mem_ref_info (tree to, tree from) { /* Copy the annotation, to preserve the aliasing information. */ TMR_TAG (to) = TMR_TAG (from); /* And the info about the original reference. */ TMR_ORIGINAL (to) = TMR_ORIGINAL (from); } /* Move constants in target_mem_ref REF to offset. Returns the new target mem ref if anything changes, NULL_TREE otherwise. */ tree maybe_fold_tmr (tree ref) { struct mem_address addr; bool changed = false; tree ret, off; get_address_description (ref, &addr); if (addr.base && TREE_CODE (addr.base) == INTEGER_CST) { if (addr.offset) addr.offset = fold_binary_to_constant (PLUS_EXPR, sizetype, addr.offset, fold_convert (sizetype, addr.base)); else addr.offset = addr.base; addr.base = NULL_TREE; changed = true; } if (addr.index && TREE_CODE (addr.index) == INTEGER_CST) { off = addr.index; if (addr.step) { off = fold_binary_to_constant (MULT_EXPR, sizetype, off, addr.step); addr.step = NULL_TREE; } if (addr.offset) { addr.offset = fold_binary_to_constant (PLUS_EXPR, sizetype, addr.offset, off); } else addr.offset = off; addr.index = NULL_TREE; changed = true; } if (!changed) return NULL_TREE; ret = create_mem_ref_raw (TREE_TYPE (ref), &addr); if (!ret) return NULL_TREE; copy_mem_ref_info (ret, ref); return ret; } /* Dump PARTS to FILE. */ extern void dump_mem_address (FILE *, struct mem_address *); void dump_mem_address (FILE *file, struct mem_address *parts) { if (parts->symbol) { fprintf (file, "symbol: "); print_generic_expr (file, parts->symbol, TDF_SLIM); fprintf (file, "\n"); } if (parts->base) { fprintf (file, "base: "); print_generic_expr (file, parts->base, TDF_SLIM); fprintf (file, "\n"); } if (parts->index) { fprintf (file, "index: "); print_generic_expr (file, parts->index, TDF_SLIM); fprintf (file, "\n"); } if (parts->step) { fprintf (file, "step: "); print_generic_expr (file, parts->step, TDF_SLIM); fprintf (file, "\n"); } if (parts->offset) { fprintf (file, "offset: "); print_generic_expr (file, parts->offset, TDF_SLIM); fprintf (file, "\n"); } } #include "gt-tree-ssa-address.h"