/* Global, SSA-based optimizations using mathematical identities. Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011 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 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 . */ /* Currently, the only mini-pass in this file tries to CSE reciprocal operations. These are common in sequences such as this one: modulus = sqrt(x*x + y*y + z*z); x = x / modulus; y = y / modulus; z = z / modulus; that can be optimized to modulus = sqrt(x*x + y*y + z*z); rmodulus = 1.0 / modulus; x = x * rmodulus; y = y * rmodulus; z = z * rmodulus; We do this for loop invariant divisors, and with this pass whenever we notice that a division has the same divisor multiple times. Of course, like in PRE, we don't insert a division if a dominator already has one. However, this cannot be done as an extension of PRE for several reasons. First of all, with some experiments it was found out that the transformation is not always useful if there are only two divisions hy the same divisor. This is probably because modern processors can pipeline the divisions; on older, in-order processors it should still be effective to optimize two divisions by the same number. We make this a param, and it shall be called N in the remainder of this comment. Second, if trapping math is active, we have less freedom on where to insert divisions: we can only do so in basic blocks that already contain one. (If divisions don't trap, instead, we can insert divisions elsewhere, which will be in blocks that are common dominators of those that have the division). We really don't want to compute the reciprocal unless a division will be found. To do this, we won't insert the division in a basic block that has less than N divisions *post-dominating* it. The algorithm constructs a subset of the dominator tree, holding the blocks containing the divisions and the common dominators to them, and walk it twice. The first walk is in post-order, and it annotates each block with the number of divisions that post-dominate it: this gives information on where divisions can be inserted profitably. The second walk is in pre-order, and it inserts divisions as explained above, and replaces divisions by multiplications. In the best case, the cost of the pass is O(n_statements). In the worst-case, the cost is due to creating the dominator tree subset, with a cost of O(n_basic_blocks ^ 2); however this can only happen for n_statements / n_basic_blocks statements. So, the amortized cost of creating the dominator tree subset is O(n_basic_blocks) and the worst-case cost of the pass is O(n_statements * n_basic_blocks). More practically, the cost will be small because there are few divisions, and they tend to be in the same basic block, so insert_bb is called very few times. If we did this using domwalk.c, an efficient implementation would have to work on all the variables in a single pass, because we could not work on just a subset of the dominator tree, as we do now, and the cost would also be something like O(n_statements * n_basic_blocks). The data structures would be more complex in order to work on all the variables in a single pass. */ #include "config.h" #include "system.h" #include "coretypes.h" #include "tm.h" #include "flags.h" #include "tree.h" #include "tree-flow.h" #include "timevar.h" #include "tree-pass.h" #include "alloc-pool.h" #include "basic-block.h" #include "target.h" #include "gimple-pretty-print.h" /* FIXME: RTL headers have to be included here for optabs. */ #include "rtl.h" /* Because optabs.h wants enum rtx_code. */ #include "expr.h" /* Because optabs.h wants sepops. */ #include "optabs.h" /* This structure represents one basic block that either computes a division, or is a common dominator for basic block that compute a division. */ struct occurrence { /* The basic block represented by this structure. */ basic_block bb; /* If non-NULL, the SSA_NAME holding the definition for a reciprocal inserted in BB. */ tree recip_def; /* If non-NULL, the GIMPLE_ASSIGN for a reciprocal computation that was inserted in BB. */ gimple recip_def_stmt; /* Pointer to a list of "struct occurrence"s for blocks dominated by BB. */ struct occurrence *children; /* Pointer to the next "struct occurrence"s in the list of blocks sharing a common dominator. */ struct occurrence *next; /* The number of divisions that are in BB before compute_merit. The number of divisions that are in BB or post-dominate it after compute_merit. */ int num_divisions; /* True if the basic block has a division, false if it is a common dominator for basic blocks that do. If it is false and trapping math is active, BB is not a candidate for inserting a reciprocal. */ bool bb_has_division; }; static struct { /* Number of 1.0/X ops inserted. */ int rdivs_inserted; /* Number of 1.0/FUNC ops inserted. */ int rfuncs_inserted; } reciprocal_stats; static struct { /* Number of cexpi calls inserted. */ int inserted; } sincos_stats; static struct { /* Number of hand-written 32-bit bswaps found. */ int found_32bit; /* Number of hand-written 64-bit bswaps found. */ int found_64bit; } bswap_stats; static struct { /* Number of widening multiplication ops inserted. */ int widen_mults_inserted; /* Number of integer multiply-and-accumulate ops inserted. */ int maccs_inserted; /* Number of fp fused multiply-add ops inserted. */ int fmas_inserted; } widen_mul_stats; /* The instance of "struct occurrence" representing the highest interesting block in the dominator tree. */ static struct occurrence *occ_head; /* Allocation pool for getting instances of "struct occurrence". */ static alloc_pool occ_pool; /* Allocate and return a new struct occurrence for basic block BB, and whose children list is headed by CHILDREN. */ static struct occurrence * occ_new (basic_block bb, struct occurrence *children) { struct occurrence *occ; bb->aux = occ = (struct occurrence *) pool_alloc (occ_pool); memset (occ, 0, sizeof (struct occurrence)); occ->bb = bb; occ->children = children; return occ; } /* Insert NEW_OCC into our subset of the dominator tree. P_HEAD points to a list of "struct occurrence"s, one per basic block, having IDOM as their common dominator. We try to insert NEW_OCC as deep as possible in the tree, and we also insert any other block that is a common dominator for BB and one block already in the tree. */ static void insert_bb (struct occurrence *new_occ, basic_block idom, struct occurrence **p_head) { struct occurrence *occ, **p_occ; for (p_occ = p_head; (occ = *p_occ) != NULL; ) { basic_block bb = new_occ->bb, occ_bb = occ->bb; basic_block dom = nearest_common_dominator (CDI_DOMINATORS, occ_bb, bb); if (dom == bb) { /* BB dominates OCC_BB. OCC becomes NEW_OCC's child: remove OCC from its list. */ *p_occ = occ->next; occ->next = new_occ->children; new_occ->children = occ; /* Try the next block (it may as well be dominated by BB). */ } else if (dom == occ_bb) { /* OCC_BB dominates BB. Tail recurse to look deeper. */ insert_bb (new_occ, dom, &occ->children); return; } else if (dom != idom) { gcc_assert (!dom->aux); /* There is a dominator between IDOM and BB, add it and make two children out of NEW_OCC and OCC. First, remove OCC from its list. */ *p_occ = occ->next; new_occ->next = occ; occ->next = NULL; /* None of the previous blocks has DOM as a dominator: if we tail recursed, we would reexamine them uselessly. Just switch BB with DOM, and go on looking for blocks dominated by DOM. */ new_occ = occ_new (dom, new_occ); } else { /* Nothing special, go on with the next element. */ p_occ = &occ->next; } } /* No place was found as a child of IDOM. Make BB a sibling of IDOM. */ new_occ->next = *p_head; *p_head = new_occ; } /* Register that we found a division in BB. */ static inline void register_division_in (basic_block bb) { struct occurrence *occ; occ = (struct occurrence *) bb->aux; if (!occ) { occ = occ_new (bb, NULL); insert_bb (occ, ENTRY_BLOCK_PTR, &occ_head); } occ->bb_has_division = true; occ->num_divisions++; } /* Compute the number of divisions that postdominate each block in OCC and its children. */ static void compute_merit (struct occurrence *occ) { struct occurrence *occ_child; basic_block dom = occ->bb; for (occ_child = occ->children; occ_child; occ_child = occ_child->next) { basic_block bb; if (occ_child->children) compute_merit (occ_child); if (flag_exceptions) bb = single_noncomplex_succ (dom); else bb = dom; if (dominated_by_p (CDI_POST_DOMINATORS, bb, occ_child->bb)) occ->num_divisions += occ_child->num_divisions; } } /* Return whether USE_STMT is a floating-point division by DEF. */ static inline bool is_division_by (gimple use_stmt, tree def) { return is_gimple_assign (use_stmt) && gimple_assign_rhs_code (use_stmt) == RDIV_EXPR && gimple_assign_rhs2 (use_stmt) == def /* Do not recognize x / x as valid division, as we are getting confused later by replacing all immediate uses x in such a stmt. */ && gimple_assign_rhs1 (use_stmt) != def; } /* Walk the subset of the dominator tree rooted at OCC, setting the RECIP_DEF field to a definition of 1.0 / DEF that can be used in the given basic block. The field may be left NULL, of course, if it is not possible or profitable to do the optimization. DEF_BSI is an iterator pointing at the statement defining DEF. If RECIP_DEF is set, a dominator already has a computation that can be used. */ static void insert_reciprocals (gimple_stmt_iterator *def_gsi, struct occurrence *occ, tree def, tree recip_def, int threshold) { tree type; gimple new_stmt; gimple_stmt_iterator gsi; struct occurrence *occ_child; if (!recip_def && (occ->bb_has_division || !flag_trapping_math) && occ->num_divisions >= threshold) { /* Make a variable with the replacement and substitute it. */ type = TREE_TYPE (def); recip_def = make_rename_temp (type, "reciptmp"); new_stmt = gimple_build_assign_with_ops (RDIV_EXPR, recip_def, build_one_cst (type), def); if (occ->bb_has_division) { /* Case 1: insert before an existing division. */ gsi = gsi_after_labels (occ->bb); while (!gsi_end_p (gsi) && !is_division_by (gsi_stmt (gsi), def)) gsi_next (&gsi); gsi_insert_before (&gsi, new_stmt, GSI_SAME_STMT); } else if (def_gsi && occ->bb == def_gsi->bb) { /* Case 2: insert right after the definition. Note that this will never happen if the definition statement can throw, because in that case the sole successor of the statement's basic block will dominate all the uses as well. */ gsi_insert_after (def_gsi, new_stmt, GSI_NEW_STMT); } else { /* Case 3: insert in a basic block not containing defs/uses. */ gsi = gsi_after_labels (occ->bb); gsi_insert_before (&gsi, new_stmt, GSI_SAME_STMT); } reciprocal_stats.rdivs_inserted++; occ->recip_def_stmt = new_stmt; } occ->recip_def = recip_def; for (occ_child = occ->children; occ_child; occ_child = occ_child->next) insert_reciprocals (def_gsi, occ_child, def, recip_def, threshold); } /* Replace the division at USE_P with a multiplication by the reciprocal, if possible. */ static inline void replace_reciprocal (use_operand_p use_p) { gimple use_stmt = USE_STMT (use_p); basic_block bb = gimple_bb (use_stmt); struct occurrence *occ = (struct occurrence *) bb->aux; if (optimize_bb_for_speed_p (bb) && occ->recip_def && use_stmt != occ->recip_def_stmt) { gimple_assign_set_rhs_code (use_stmt, MULT_EXPR); SET_USE (use_p, occ->recip_def); fold_stmt_inplace (use_stmt); update_stmt (use_stmt); } } /* Free OCC and return one more "struct occurrence" to be freed. */ static struct occurrence * free_bb (struct occurrence *occ) { struct occurrence *child, *next; /* First get the two pointers hanging off OCC. */ next = occ->next; child = occ->children; occ->bb->aux = NULL; pool_free (occ_pool, occ); /* Now ensure that we don't recurse unless it is necessary. */ if (!child) return next; else { while (next) next = free_bb (next); return child; } } /* Look for floating-point divisions among DEF's uses, and try to replace them by multiplications with the reciprocal. Add as many statements computing the reciprocal as needed. DEF must be a GIMPLE register of a floating-point type. */ static void execute_cse_reciprocals_1 (gimple_stmt_iterator *def_gsi, tree def) { use_operand_p use_p; imm_use_iterator use_iter; struct occurrence *occ; int count = 0, threshold; gcc_assert (FLOAT_TYPE_P (TREE_TYPE (def)) && is_gimple_reg (def)); FOR_EACH_IMM_USE_FAST (use_p, use_iter, def) { gimple use_stmt = USE_STMT (use_p); if (is_division_by (use_stmt, def)) { register_division_in (gimple_bb (use_stmt)); count++; } } /* Do the expensive part only if we can hope to optimize something. */ threshold = targetm.min_divisions_for_recip_mul (TYPE_MODE (TREE_TYPE (def))); if (count >= threshold) { gimple use_stmt; for (occ = occ_head; occ; occ = occ->next) { compute_merit (occ); insert_reciprocals (def_gsi, occ, def, NULL, threshold); } FOR_EACH_IMM_USE_STMT (use_stmt, use_iter, def) { if (is_division_by (use_stmt, def)) { FOR_EACH_IMM_USE_ON_STMT (use_p, use_iter) replace_reciprocal (use_p); } } } for (occ = occ_head; occ; ) occ = free_bb (occ); occ_head = NULL; } static bool gate_cse_reciprocals (void) { return optimize && flag_reciprocal_math; } /* Go through all the floating-point SSA_NAMEs, and call execute_cse_reciprocals_1 on each of them. */ static unsigned int execute_cse_reciprocals (void) { basic_block bb; tree arg; occ_pool = create_alloc_pool ("dominators for recip", sizeof (struct occurrence), n_basic_blocks / 3 + 1); memset (&reciprocal_stats, 0, sizeof (reciprocal_stats)); calculate_dominance_info (CDI_DOMINATORS); calculate_dominance_info (CDI_POST_DOMINATORS); #ifdef ENABLE_CHECKING FOR_EACH_BB (bb) gcc_assert (!bb->aux); #endif for (arg = DECL_ARGUMENTS (cfun->decl); arg; arg = DECL_CHAIN (arg)) if (gimple_default_def (cfun, arg) && FLOAT_TYPE_P (TREE_TYPE (arg)) && is_gimple_reg (arg)) execute_cse_reciprocals_1 (NULL, gimple_default_def (cfun, arg)); FOR_EACH_BB (bb) { gimple_stmt_iterator gsi; gimple phi; tree def; for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) { phi = gsi_stmt (gsi); def = PHI_RESULT (phi); if (FLOAT_TYPE_P (TREE_TYPE (def)) && is_gimple_reg (def)) execute_cse_reciprocals_1 (NULL, def); } for (gsi = gsi_after_labels (bb); !gsi_end_p (gsi); gsi_next (&gsi)) { gimple stmt = gsi_stmt (gsi); if (gimple_has_lhs (stmt) && (def = SINGLE_SSA_TREE_OPERAND (stmt, SSA_OP_DEF)) != NULL && FLOAT_TYPE_P (TREE_TYPE (def)) && TREE_CODE (def) == SSA_NAME) execute_cse_reciprocals_1 (&gsi, def); } if (optimize_bb_for_size_p (bb)) continue; /* Scan for a/func(b) and convert it to reciprocal a*rfunc(b). */ for (gsi = gsi_after_labels (bb); !gsi_end_p (gsi); gsi_next (&gsi)) { gimple stmt = gsi_stmt (gsi); tree fndecl; if (is_gimple_assign (stmt) && gimple_assign_rhs_code (stmt) == RDIV_EXPR) { tree arg1 = gimple_assign_rhs2 (stmt); gimple stmt1; if (TREE_CODE (arg1) != SSA_NAME) continue; stmt1 = SSA_NAME_DEF_STMT (arg1); if (is_gimple_call (stmt1) && gimple_call_lhs (stmt1) && (fndecl = gimple_call_fndecl (stmt1)) && (DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL || DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_MD)) { enum built_in_function code; bool md_code, fail; imm_use_iterator ui; use_operand_p use_p; code = DECL_FUNCTION_CODE (fndecl); md_code = DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_MD; fndecl = targetm.builtin_reciprocal (code, md_code, false); if (!fndecl) continue; /* Check that all uses of the SSA name are divisions, otherwise replacing the defining statement will do the wrong thing. */ fail = false; FOR_EACH_IMM_USE_FAST (use_p, ui, arg1) { gimple stmt2 = USE_STMT (use_p); if (is_gimple_debug (stmt2)) continue; if (!is_gimple_assign (stmt2) || gimple_assign_rhs_code (stmt2) != RDIV_EXPR || gimple_assign_rhs1 (stmt2) == arg1 || gimple_assign_rhs2 (stmt2) != arg1) { fail = true; break; } } if (fail) continue; gimple_replace_lhs (stmt1, arg1); gimple_call_set_fndecl (stmt1, fndecl); update_stmt (stmt1); reciprocal_stats.rfuncs_inserted++; FOR_EACH_IMM_USE_STMT (stmt, ui, arg1) { gimple_assign_set_rhs_code (stmt, MULT_EXPR); fold_stmt_inplace (stmt); update_stmt (stmt); } } } } } statistics_counter_event (cfun, "reciprocal divs inserted", reciprocal_stats.rdivs_inserted); statistics_counter_event (cfun, "reciprocal functions inserted", reciprocal_stats.rfuncs_inserted); free_dominance_info (CDI_DOMINATORS); free_dominance_info (CDI_POST_DOMINATORS); free_alloc_pool (occ_pool); return 0; } struct gimple_opt_pass pass_cse_reciprocals = { { GIMPLE_PASS, "recip", /* name */ gate_cse_reciprocals, /* gate */ execute_cse_reciprocals, /* execute */ NULL, /* sub */ NULL, /* next */ 0, /* static_pass_number */ TV_NONE, /* tv_id */ PROP_ssa, /* properties_required */ 0, /* properties_provided */ 0, /* properties_destroyed */ 0, /* todo_flags_start */ TODO_update_ssa | TODO_verify_ssa | TODO_verify_stmts /* todo_flags_finish */ } }; /* Records an occurrence at statement USE_STMT in the vector of trees STMTS if it is dominated by *TOP_BB or dominates it or this basic block is not yet initialized. Returns true if the occurrence was pushed on the vector. Adjusts *TOP_BB to be the basic block dominating all statements in the vector. */ static bool maybe_record_sincos (VEC(gimple, heap) **stmts, basic_block *top_bb, gimple use_stmt) { basic_block use_bb = gimple_bb (use_stmt); if (*top_bb && (*top_bb == use_bb || dominated_by_p (CDI_DOMINATORS, use_bb, *top_bb))) VEC_safe_push (gimple, heap, *stmts, use_stmt); else if (!*top_bb || dominated_by_p (CDI_DOMINATORS, *top_bb, use_bb)) { VEC_safe_push (gimple, heap, *stmts, use_stmt); *top_bb = use_bb; } else return false; return true; } /* Look for sin, cos and cexpi calls with the same argument NAME and create a single call to cexpi CSEing the result in this case. We first walk over all immediate uses of the argument collecting statements that we can CSE in a vector and in a second pass replace the statement rhs with a REALPART or IMAGPART expression on the result of the cexpi call we insert before the use statement that dominates all other candidates. */ static bool execute_cse_sincos_1 (tree name) { gimple_stmt_iterator gsi; imm_use_iterator use_iter; tree fndecl, res, type; gimple def_stmt, use_stmt, stmt; int seen_cos = 0, seen_sin = 0, seen_cexpi = 0; VEC(gimple, heap) *stmts = NULL; basic_block top_bb = NULL; int i; bool cfg_changed = false; type = TREE_TYPE (name); FOR_EACH_IMM_USE_STMT (use_stmt, use_iter, name) { if (gimple_code (use_stmt) != GIMPLE_CALL || !gimple_call_lhs (use_stmt) || !(fndecl = gimple_call_fndecl (use_stmt)) || DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_NORMAL) continue; switch (DECL_FUNCTION_CODE (fndecl)) { CASE_FLT_FN (BUILT_IN_COS): seen_cos |= maybe_record_sincos (&stmts, &top_bb, use_stmt) ? 1 : 0; break; CASE_FLT_FN (BUILT_IN_SIN): seen_sin |= maybe_record_sincos (&stmts, &top_bb, use_stmt) ? 1 : 0; break; CASE_FLT_FN (BUILT_IN_CEXPI): seen_cexpi |= maybe_record_sincos (&stmts, &top_bb, use_stmt) ? 1 : 0; break; default:; } } if (seen_cos + seen_sin + seen_cexpi <= 1) { VEC_free(gimple, heap, stmts); return false; } /* Simply insert cexpi at the beginning of top_bb but not earlier than the name def statement. */ fndecl = mathfn_built_in (type, BUILT_IN_CEXPI); if (!fndecl) return false; res = create_tmp_reg (TREE_TYPE (TREE_TYPE (fndecl)), "sincostmp"); stmt = gimple_build_call (fndecl, 1, name); res = make_ssa_name (res, stmt); gimple_call_set_lhs (stmt, res); def_stmt = SSA_NAME_DEF_STMT (name); if (!SSA_NAME_IS_DEFAULT_DEF (name) && gimple_code (def_stmt) != GIMPLE_PHI && gimple_bb (def_stmt) == top_bb) { gsi = gsi_for_stmt (def_stmt); gsi_insert_after (&gsi, stmt, GSI_SAME_STMT); } else { gsi = gsi_after_labels (top_bb); gsi_insert_before (&gsi, stmt, GSI_SAME_STMT); } update_stmt (stmt); sincos_stats.inserted++; /* And adjust the recorded old call sites. */ for (i = 0; VEC_iterate(gimple, stmts, i, use_stmt); ++i) { tree rhs = NULL; fndecl = gimple_call_fndecl (use_stmt); switch (DECL_FUNCTION_CODE (fndecl)) { CASE_FLT_FN (BUILT_IN_COS): rhs = fold_build1 (REALPART_EXPR, type, res); break; CASE_FLT_FN (BUILT_IN_SIN): rhs = fold_build1 (IMAGPART_EXPR, type, res); break; CASE_FLT_FN (BUILT_IN_CEXPI): rhs = res; break; default:; gcc_unreachable (); } /* Replace call with a copy. */ stmt = gimple_build_assign (gimple_call_lhs (use_stmt), rhs); gsi = gsi_for_stmt (use_stmt); gsi_replace (&gsi, stmt, true); if (gimple_purge_dead_eh_edges (gimple_bb (stmt))) cfg_changed = true; } VEC_free(gimple, heap, stmts); return cfg_changed; } /* To evaluate powi(x,n), the floating point value x raised to the constant integer exponent n, we use a hybrid algorithm that combines the "window method" with look-up tables. For an introduction to exponentiation algorithms and "addition chains", see section 4.6.3, "Evaluation of Powers" of Donald E. Knuth, "Seminumerical Algorithms", Vol. 2, "The Art of Computer Programming", 3rd Edition, 1998, and Daniel M. Gordon, "A Survey of Fast Exponentiation Methods", Journal of Algorithms, Vol. 27, pp. 129-146, 1998. */ /* Provide a default value for POWI_MAX_MULTS, the maximum number of multiplications to inline before calling the system library's pow function. powi(x,n) requires at worst 2*bits(n)-2 multiplications, so this default never requires calling pow, powf or powl. */ #ifndef POWI_MAX_MULTS #define POWI_MAX_MULTS (2*HOST_BITS_PER_WIDE_INT-2) #endif /* The size of the "optimal power tree" lookup table. All exponents less than this value are simply looked up in the powi_table below. This threshold is also used to size the cache of pseudo registers that hold intermediate results. */ #define POWI_TABLE_SIZE 256 /* The size, in bits of the window, used in the "window method" exponentiation algorithm. This is equivalent to a radix of (1<= POWI_TABLE_SIZE) { if (val & 1) { digit = val & ((1 << POWI_WINDOW_SIZE) - 1); result += powi_lookup_cost (digit, cache) + POWI_WINDOW_SIZE + 1; val >>= POWI_WINDOW_SIZE; } else { val >>= 1; result++; } } return result + powi_lookup_cost (val, cache); } /* Recursive subroutine of powi_as_mults. This function takes the array, CACHE, of already calculated exponents and an exponent N and returns a tree that corresponds to CACHE[1]**N, with type TYPE. */ static tree powi_as_mults_1 (gimple_stmt_iterator *gsi, location_t loc, tree type, HOST_WIDE_INT n, tree *cache, tree target) { tree op0, op1, ssa_target; unsigned HOST_WIDE_INT digit; gimple mult_stmt; if (n < POWI_TABLE_SIZE && cache[n]) return cache[n]; ssa_target = make_ssa_name (target, NULL); if (n < POWI_TABLE_SIZE) { cache[n] = ssa_target; op0 = powi_as_mults_1 (gsi, loc, type, n - powi_table[n], cache, target); op1 = powi_as_mults_1 (gsi, loc, type, powi_table[n], cache, target); } else if (n & 1) { digit = n & ((1 << POWI_WINDOW_SIZE) - 1); op0 = powi_as_mults_1 (gsi, loc, type, n - digit, cache, target); op1 = powi_as_mults_1 (gsi, loc, type, digit, cache, target); } else { op0 = powi_as_mults_1 (gsi, loc, type, n >> 1, cache, target); op1 = op0; } mult_stmt = gimple_build_assign_with_ops (MULT_EXPR, ssa_target, op0, op1); gimple_set_location (mult_stmt, loc); gsi_insert_before (gsi, mult_stmt, GSI_SAME_STMT); return ssa_target; } /* Convert ARG0**N to a tree of multiplications of ARG0 with itself. This function needs to be kept in sync with powi_cost above. */ static tree powi_as_mults (gimple_stmt_iterator *gsi, location_t loc, tree arg0, HOST_WIDE_INT n) { tree cache[POWI_TABLE_SIZE], result, type = TREE_TYPE (arg0), target; gimple div_stmt; if (n == 0) return build_real (type, dconst1); memset (cache, 0, sizeof (cache)); cache[1] = arg0; target = create_tmp_reg (type, "powmult"); add_referenced_var (target); result = powi_as_mults_1 (gsi, loc, type, (n < 0) ? -n : n, cache, target); if (n >= 0) return result; /* If the original exponent was negative, reciprocate the result. */ target = make_ssa_name (target, NULL); div_stmt = gimple_build_assign_with_ops (RDIV_EXPR, target, build_real (type, dconst1), result); gimple_set_location (div_stmt, loc); gsi_insert_before (gsi, div_stmt, GSI_SAME_STMT); return target; } /* ARG0 and N are the two arguments to a powi builtin in GSI with location info LOC. If the arguments are appropriate, create an equivalent sequence of statements prior to GSI using an optimal number of multiplications, and return an expession holding the result. */ static tree gimple_expand_builtin_powi (gimple_stmt_iterator *gsi, location_t loc, tree arg0, HOST_WIDE_INT n) { /* Avoid largest negative number. */ if (n != -n && ((n >= -1 && n <= 2) || (optimize_function_for_speed_p (cfun) && powi_cost (n) <= POWI_MAX_MULTS))) return powi_as_mults (gsi, loc, arg0, n); return NULL_TREE; } /* Build a gimple call statement that calls FN with argument ARG. Set the lhs of the call statement to a fresh SSA name for variable VAR. If VAR is NULL, first allocate it. Insert the statement prior to GSI's current position, and return the fresh SSA name. */ static tree build_and_insert_call (gimple_stmt_iterator *gsi, location_t loc, tree *var, tree fn, tree arg) { gimple call_stmt; tree ssa_target; if (!*var) { *var = create_tmp_reg (TREE_TYPE (arg), "powroot"); add_referenced_var (*var); } call_stmt = gimple_build_call (fn, 1, arg); ssa_target = make_ssa_name (*var, NULL); gimple_set_lhs (call_stmt, ssa_target); gimple_set_location (call_stmt, loc); gsi_insert_before (gsi, call_stmt, GSI_SAME_STMT); return ssa_target; } /* Build a gimple binary operation with the given CODE and arguments ARG0, ARG1, assigning the result to a new SSA name for variable TARGET. Insert the statement prior to GSI's current position, and return the fresh SSA name.*/ static tree build_and_insert_binop (gimple_stmt_iterator *gsi, location_t loc, tree target, enum tree_code code, tree arg0, tree arg1) { tree result = make_ssa_name (target, NULL); gimple stmt = gimple_build_assign_with_ops (code, result, arg0, arg1); gimple_set_location (stmt, loc); gsi_insert_before (gsi, stmt, GSI_SAME_STMT); return result; } /* Build a gimple reference operation with the given CODE and argument ARG, assigning the result to a new SSA name for variable TARGET. Insert the statement prior to GSI's current position, and return the fresh SSA name. */ static inline tree build_and_insert_ref (gimple_stmt_iterator *gsi, location_t loc, tree type, tree target, enum tree_code code, tree arg0) { tree result = make_ssa_name (target, NULL); gimple stmt = gimple_build_assign (result, build1 (code, type, arg0)); gimple_set_location (stmt, loc); gsi_insert_before (gsi, stmt, GSI_SAME_STMT); return result; } /* ARG0 and ARG1 are the two arguments to a pow builtin call in GSI with location info LOC. If possible, create an equivalent and less expensive sequence of statements prior to GSI, and return an expession holding the result. */ static tree gimple_expand_builtin_pow (gimple_stmt_iterator *gsi, location_t loc, tree arg0, tree arg1) { REAL_VALUE_TYPE c, cint, dconst1_4, dconst3_4, dconst1_3, dconst1_6; REAL_VALUE_TYPE c2, dconst3; HOST_WIDE_INT n; tree type, sqrtfn, cbrtfn, sqrt_arg0, sqrt_sqrt, result, cbrt_x, powi_cbrt_x; tree target = NULL_TREE; enum machine_mode mode; bool hw_sqrt_exists; /* If the exponent isn't a constant, there's nothing of interest to be done. */ if (TREE_CODE (arg1) != REAL_CST) return NULL_TREE; /* If the exponent is equivalent to an integer, expand to an optimal multiplication sequence when profitable. */ c = TREE_REAL_CST (arg1); n = real_to_integer (&c); real_from_integer (&cint, VOIDmode, n, n < 0 ? -1 : 0, 0); if (real_identical (&c, &cint) && ((n >= -1 && n <= 2) || (flag_unsafe_math_optimizations && optimize_insn_for_speed_p () && powi_cost (n) <= POWI_MAX_MULTS))) return gimple_expand_builtin_powi (gsi, loc, arg0, n); /* Attempt various optimizations using sqrt and cbrt. */ type = TREE_TYPE (arg0); mode = TYPE_MODE (type); sqrtfn = mathfn_built_in (type, BUILT_IN_SQRT); /* Optimize pow(x,0.5) = sqrt(x). This replacement is always safe unless signed zeros must be maintained. pow(-0,0.5) = +0, while sqrt(-0) = -0. */ if (sqrtfn && REAL_VALUES_EQUAL (c, dconsthalf) && !HONOR_SIGNED_ZEROS (mode)) return build_and_insert_call (gsi, loc, &target, sqrtfn, arg0); /* Optimize pow(x,0.25) = sqrt(sqrt(x)). Assume on most machines that a builtin sqrt instruction is smaller than a call to pow with 0.25, so do this optimization even if -Os. Don't do this optimization if we don't have a hardware sqrt insn. */ dconst1_4 = dconst1; SET_REAL_EXP (&dconst1_4, REAL_EXP (&dconst1_4) - 2); hw_sqrt_exists = optab_handler (sqrt_optab, mode) != CODE_FOR_nothing; if (flag_unsafe_math_optimizations && sqrtfn && REAL_VALUES_EQUAL (c, dconst1_4) && hw_sqrt_exists) { /* sqrt(x) */ sqrt_arg0 = build_and_insert_call (gsi, loc, &target, sqrtfn, arg0); /* sqrt(sqrt(x)) */ return build_and_insert_call (gsi, loc, &target, sqrtfn, sqrt_arg0); } /* Optimize pow(x,0.75) = sqrt(x) * sqrt(sqrt(x)) unless we are optimizing for space. Don't do this optimization if we don't have a hardware sqrt insn. */ real_from_integer (&dconst3_4, VOIDmode, 3, 0, 0); SET_REAL_EXP (&dconst3_4, REAL_EXP (&dconst3_4) - 2); if (flag_unsafe_math_optimizations && sqrtfn && optimize_function_for_speed_p (cfun) && REAL_VALUES_EQUAL (c, dconst3_4) && hw_sqrt_exists) { /* sqrt(x) */ sqrt_arg0 = build_and_insert_call (gsi, loc, &target, sqrtfn, arg0); /* sqrt(sqrt(x)) */ sqrt_sqrt = build_and_insert_call (gsi, loc, &target, sqrtfn, sqrt_arg0); /* sqrt(x) * sqrt(sqrt(x)) */ return build_and_insert_binop (gsi, loc, target, MULT_EXPR, sqrt_arg0, sqrt_sqrt); } /* Optimize pow(x,1./3.) = cbrt(x). This requires unsafe math optimizations since 1./3. is not exactly representable. If x is negative and finite, the correct value of pow(x,1./3.) is a NaN with the "invalid" exception raised, because the value of 1./3. actually has an even denominator. The correct value of cbrt(x) is a negative real value. */ cbrtfn = mathfn_built_in (type, BUILT_IN_CBRT); dconst1_3 = real_value_truncate (mode, dconst_third ()); if (flag_unsafe_math_optimizations && cbrtfn && (gimple_val_nonnegative_real_p (arg0) || !HONOR_NANS (mode)) && REAL_VALUES_EQUAL (c, dconst1_3)) return build_and_insert_call (gsi, loc, &target, cbrtfn, arg0); /* Optimize pow(x,1./6.) = cbrt(sqrt(x)). Don't do this optimization if we don't have a hardware sqrt insn. */ dconst1_6 = dconst1_3; SET_REAL_EXP (&dconst1_6, REAL_EXP (&dconst1_6) - 1); if (flag_unsafe_math_optimizations && sqrtfn && cbrtfn && (gimple_val_nonnegative_real_p (arg0) || !HONOR_NANS (mode)) && optimize_function_for_speed_p (cfun) && hw_sqrt_exists && REAL_VALUES_EQUAL (c, dconst1_6)) { /* sqrt(x) */ sqrt_arg0 = build_and_insert_call (gsi, loc, &target, sqrtfn, arg0); /* cbrt(sqrt(x)) */ return build_and_insert_call (gsi, loc, &target, cbrtfn, sqrt_arg0); } /* Optimize pow(x,c), where n = 2c for some nonzero integer n, into sqrt(x) * powi(x, n/2), n > 0; 1.0 / (sqrt(x) * powi(x, abs(n/2))), n < 0. Do not calculate the powi factor when n/2 = 0. */ real_arithmetic (&c2, MULT_EXPR, &c, &dconst2); n = real_to_integer (&c2); real_from_integer (&cint, VOIDmode, n, n < 0 ? -1 : 0, 0); if (flag_unsafe_math_optimizations && sqrtfn && real_identical (&c2, &cint)) { tree powi_x_ndiv2 = NULL_TREE; /* Attempt to fold powi(arg0, abs(n/2)) into multiplies. If not possible or profitable, give up. Skip the degenerate case when n is 1 or -1, where the result is always 1. */ if (abs_hwi (n) != 1) { powi_x_ndiv2 = gimple_expand_builtin_powi (gsi, loc, arg0, abs_hwi (n / 2)); if (!powi_x_ndiv2) return NULL_TREE; } /* Calculate sqrt(x). When n is not 1 or -1, multiply it by the result of the optimal multiply sequence just calculated. */ sqrt_arg0 = build_and_insert_call (gsi, loc, &target, sqrtfn, arg0); if (abs_hwi (n) == 1) result = sqrt_arg0; else result = build_and_insert_binop (gsi, loc, target, MULT_EXPR, sqrt_arg0, powi_x_ndiv2); /* If n is negative, reciprocate the result. */ if (n < 0) result = build_and_insert_binop (gsi, loc, target, RDIV_EXPR, build_real (type, dconst1), result); return result; } /* Optimize pow(x,c), where 3c = n for some nonzero integer n, into powi(x, n/3) * powi(cbrt(x), n%3), n > 0; 1.0 / (powi(x, abs(n)/3) * powi(cbrt(x), abs(n)%3)), n < 0. Do not calculate the first factor when n/3 = 0. As cbrt(x) is different from pow(x, 1./3.) due to rounding and behavior with negative x, we need to constrain this transformation to unsafe math and positive x or finite math. */ real_from_integer (&dconst3, VOIDmode, 3, 0, 0); real_arithmetic (&c2, MULT_EXPR, &c, &dconst3); real_round (&c2, mode, &c2); n = real_to_integer (&c2); real_from_integer (&cint, VOIDmode, n, n < 0 ? -1 : 0, 0); real_arithmetic (&c2, RDIV_EXPR, &cint, &dconst3); real_convert (&c2, mode, &c2); if (flag_unsafe_math_optimizations && cbrtfn && (gimple_val_nonnegative_real_p (arg0) || !HONOR_NANS (mode)) && real_identical (&c2, &c) && optimize_function_for_speed_p (cfun) && powi_cost (n / 3) <= POWI_MAX_MULTS) { tree powi_x_ndiv3 = NULL_TREE; /* Attempt to fold powi(arg0, abs(n/3)) into multiplies. If not possible or profitable, give up. Skip the degenerate case when abs(n) < 3, where the result is always 1. */ if (abs_hwi (n) >= 3) { powi_x_ndiv3 = gimple_expand_builtin_powi (gsi, loc, arg0, abs_hwi (n / 3)); if (!powi_x_ndiv3) return NULL_TREE; } /* Calculate powi(cbrt(x), n%3). Don't use gimple_expand_builtin_powi as that creates an unnecessary variable. Instead, just produce either cbrt(x) or cbrt(x) * cbrt(x). */ cbrt_x = build_and_insert_call (gsi, loc, &target, cbrtfn, arg0); if (abs_hwi (n) % 3 == 1) powi_cbrt_x = cbrt_x; else powi_cbrt_x = build_and_insert_binop (gsi, loc, target, MULT_EXPR, cbrt_x, cbrt_x); /* Multiply the two subexpressions, unless powi(x,abs(n)/3) = 1. */ if (abs_hwi (n) < 3) result = powi_cbrt_x; else result = build_and_insert_binop (gsi, loc, target, MULT_EXPR, powi_x_ndiv3, powi_cbrt_x); /* If n is negative, reciprocate the result. */ if (n < 0) result = build_and_insert_binop (gsi, loc, target, RDIV_EXPR, build_real (type, dconst1), result); return result; } /* No optimizations succeeded. */ return NULL_TREE; } /* ARG is the argument to a cabs builtin call in GSI with location info LOC. Create a sequence of statements prior to GSI that calculates sqrt(R*R + I*I), where R and I are the real and imaginary components of ARG, respectively. Return an expression holding the result. */ static tree gimple_expand_builtin_cabs (gimple_stmt_iterator *gsi, location_t loc, tree arg) { tree target, real_part, imag_part, addend1, addend2, sum, result; tree type = TREE_TYPE (TREE_TYPE (arg)); tree sqrtfn = mathfn_built_in (type, BUILT_IN_SQRT); enum machine_mode mode = TYPE_MODE (type); if (!flag_unsafe_math_optimizations || !optimize_bb_for_speed_p (gimple_bb (gsi_stmt (*gsi))) || !sqrtfn || optab_handler (sqrt_optab, mode) == CODE_FOR_nothing) return NULL_TREE; target = create_tmp_reg (type, "cabs"); add_referenced_var (target); real_part = build_and_insert_ref (gsi, loc, type, target, REALPART_EXPR, arg); addend1 = build_and_insert_binop (gsi, loc, target, MULT_EXPR, real_part, real_part); imag_part = build_and_insert_ref (gsi, loc, type, target, IMAGPART_EXPR, arg); addend2 = build_and_insert_binop (gsi, loc, target, MULT_EXPR, imag_part, imag_part); sum = build_and_insert_binop (gsi, loc, target, PLUS_EXPR, addend1, addend2); result = build_and_insert_call (gsi, loc, &target, sqrtfn, sum); return result; } /* Go through all calls to sin, cos and cexpi and call execute_cse_sincos_1 on the SSA_NAME argument of each of them. Also expand powi(x,n) into an optimal number of multiplies, when n is a constant. */ static unsigned int execute_cse_sincos (void) { basic_block bb; bool cfg_changed = false; calculate_dominance_info (CDI_DOMINATORS); memset (&sincos_stats, 0, sizeof (sincos_stats)); FOR_EACH_BB (bb) { gimple_stmt_iterator gsi; for (gsi = gsi_after_labels (bb); !gsi_end_p (gsi); gsi_next (&gsi)) { gimple stmt = gsi_stmt (gsi); tree fndecl; if (is_gimple_call (stmt) && gimple_call_lhs (stmt) && (fndecl = gimple_call_fndecl (stmt)) && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL) { tree arg, arg0, arg1, result; HOST_WIDE_INT n; location_t loc; switch (DECL_FUNCTION_CODE (fndecl)) { CASE_FLT_FN (BUILT_IN_COS): CASE_FLT_FN (BUILT_IN_SIN): CASE_FLT_FN (BUILT_IN_CEXPI): /* Make sure we have either sincos or cexp. */ if (!TARGET_HAS_SINCOS && !TARGET_C99_FUNCTIONS) break; arg = gimple_call_arg (stmt, 0); if (TREE_CODE (arg) == SSA_NAME) cfg_changed |= execute_cse_sincos_1 (arg); break; CASE_FLT_FN (BUILT_IN_POW): arg0 = gimple_call_arg (stmt, 0); arg1 = gimple_call_arg (stmt, 1); loc = gimple_location (stmt); result = gimple_expand_builtin_pow (&gsi, loc, arg0, arg1); if (result) { tree lhs = gimple_get_lhs (stmt); gimple new_stmt = gimple_build_assign (lhs, result); gimple_set_location (new_stmt, loc); unlink_stmt_vdef (stmt); gsi_replace (&gsi, new_stmt, true); } break; CASE_FLT_FN (BUILT_IN_POWI): arg0 = gimple_call_arg (stmt, 0); arg1 = gimple_call_arg (stmt, 1); if (!host_integerp (arg1, 0)) break; n = TREE_INT_CST_LOW (arg1); loc = gimple_location (stmt); result = gimple_expand_builtin_powi (&gsi, loc, arg0, n); if (result) { tree lhs = gimple_get_lhs (stmt); gimple new_stmt = gimple_build_assign (lhs, result); gimple_set_location (new_stmt, loc); unlink_stmt_vdef (stmt); gsi_replace (&gsi, new_stmt, true); } break; CASE_FLT_FN (BUILT_IN_CABS): arg0 = gimple_call_arg (stmt, 0); loc = gimple_location (stmt); result = gimple_expand_builtin_cabs (&gsi, loc, arg0); if (result) { tree lhs = gimple_get_lhs (stmt); gimple new_stmt = gimple_build_assign (lhs, result); gimple_set_location (new_stmt, loc); unlink_stmt_vdef (stmt); gsi_replace (&gsi, new_stmt, true); } break; default:; } } } } statistics_counter_event (cfun, "sincos statements inserted", sincos_stats.inserted); free_dominance_info (CDI_DOMINATORS); return cfg_changed ? TODO_cleanup_cfg : 0; } static bool gate_cse_sincos (void) { /* We no longer require either sincos or cexp, since powi expansion piggybacks on this pass. */ return optimize; } struct gimple_opt_pass pass_cse_sincos = { { GIMPLE_PASS, "sincos", /* name */ gate_cse_sincos, /* gate */ execute_cse_sincos, /* execute */ NULL, /* sub */ NULL, /* next */ 0, /* static_pass_number */ TV_NONE, /* tv_id */ PROP_ssa, /* properties_required */ 0, /* properties_provided */ 0, /* properties_destroyed */ 0, /* todo_flags_start */ TODO_update_ssa | TODO_verify_ssa | TODO_verify_stmts /* todo_flags_finish */ } }; /* A symbolic number is used to detect byte permutation and selection patterns. Therefore the field N contains an artificial number consisting of byte size markers: 0 - byte has the value 0 1..size - byte contains the content of the byte number indexed with that value minus one */ struct symbolic_number { unsigned HOST_WIDEST_INT n; int size; }; /* Perform a SHIFT or ROTATE operation by COUNT bits on symbolic number N. Return false if the requested operation is not permitted on a symbolic number. */ static inline bool do_shift_rotate (enum tree_code code, struct symbolic_number *n, int count) { if (count % 8 != 0) return false; /* Zero out the extra bits of N in order to avoid them being shifted into the significant bits. */ if (n->size < (int)sizeof (HOST_WIDEST_INT)) n->n &= ((unsigned HOST_WIDEST_INT)1 << (n->size * BITS_PER_UNIT)) - 1; switch (code) { case LSHIFT_EXPR: n->n <<= count; break; case RSHIFT_EXPR: n->n >>= count; break; case LROTATE_EXPR: n->n = (n->n << count) | (n->n >> ((n->size * BITS_PER_UNIT) - count)); break; case RROTATE_EXPR: n->n = (n->n >> count) | (n->n << ((n->size * BITS_PER_UNIT) - count)); break; default: return false; } /* Zero unused bits for size. */ if (n->size < (int)sizeof (HOST_WIDEST_INT)) n->n &= ((unsigned HOST_WIDEST_INT)1 << (n->size * BITS_PER_UNIT)) - 1; return true; } /* Perform sanity checking for the symbolic number N and the gimple statement STMT. */ static inline bool verify_symbolic_number_p (struct symbolic_number *n, gimple stmt) { tree lhs_type; lhs_type = gimple_expr_type (stmt); if (TREE_CODE (lhs_type) != INTEGER_TYPE) return false; if (TYPE_PRECISION (lhs_type) != n->size * BITS_PER_UNIT) return false; return true; } /* find_bswap_1 invokes itself recursively with N and tries to perform the operation given by the rhs of STMT on the result. If the operation could successfully be executed the function returns the tree expression of the source operand and NULL otherwise. */ static tree find_bswap_1 (gimple stmt, struct symbolic_number *n, int limit) { enum tree_code code; tree rhs1, rhs2 = NULL; gimple rhs1_stmt, rhs2_stmt; tree source_expr1; enum gimple_rhs_class rhs_class; if (!limit || !is_gimple_assign (stmt)) return NULL_TREE; rhs1 = gimple_assign_rhs1 (stmt); if (TREE_CODE (rhs1) != SSA_NAME) return NULL_TREE; code = gimple_assign_rhs_code (stmt); rhs_class = gimple_assign_rhs_class (stmt); rhs1_stmt = SSA_NAME_DEF_STMT (rhs1); if (rhs_class == GIMPLE_BINARY_RHS) rhs2 = gimple_assign_rhs2 (stmt); /* Handle unary rhs and binary rhs with integer constants as second operand. */ if (rhs_class == GIMPLE_UNARY_RHS || (rhs_class == GIMPLE_BINARY_RHS && TREE_CODE (rhs2) == INTEGER_CST)) { if (code != BIT_AND_EXPR && code != LSHIFT_EXPR && code != RSHIFT_EXPR && code != LROTATE_EXPR && code != RROTATE_EXPR && code != NOP_EXPR && code != CONVERT_EXPR) return NULL_TREE; source_expr1 = find_bswap_1 (rhs1_stmt, n, limit - 1); /* If find_bswap_1 returned NULL STMT is a leaf node and we have to initialize the symbolic number. */ if (!source_expr1) { /* Set up the symbolic number N by setting each byte to a value between 1 and the byte size of rhs1. The highest order byte is set to n->size and the lowest order byte to 1. */ n->size = TYPE_PRECISION (TREE_TYPE (rhs1)); if (n->size % BITS_PER_UNIT != 0) return NULL_TREE; n->size /= BITS_PER_UNIT; n->n = (sizeof (HOST_WIDEST_INT) < 8 ? 0 : (unsigned HOST_WIDEST_INT)0x08070605 << 32 | 0x04030201); if (n->size < (int)sizeof (HOST_WIDEST_INT)) n->n &= ((unsigned HOST_WIDEST_INT)1 << (n->size * BITS_PER_UNIT)) - 1; source_expr1 = rhs1; } switch (code) { case BIT_AND_EXPR: { int i; unsigned HOST_WIDEST_INT val = widest_int_cst_value (rhs2); unsigned HOST_WIDEST_INT tmp = val; /* Only constants masking full bytes are allowed. */ for (i = 0; i < n->size; i++, tmp >>= BITS_PER_UNIT) if ((tmp & 0xff) != 0 && (tmp & 0xff) != 0xff) return NULL_TREE; n->n &= val; } break; case LSHIFT_EXPR: case RSHIFT_EXPR: case LROTATE_EXPR: case RROTATE_EXPR: if (!do_shift_rotate (code, n, (int)TREE_INT_CST_LOW (rhs2))) return NULL_TREE; break; CASE_CONVERT: { int type_size; type_size = TYPE_PRECISION (gimple_expr_type (stmt)); if (type_size % BITS_PER_UNIT != 0) return NULL_TREE; if (type_size / BITS_PER_UNIT < (int)(sizeof (HOST_WIDEST_INT))) { /* If STMT casts to a smaller type mask out the bits not belonging to the target type. */ n->n &= ((unsigned HOST_WIDEST_INT)1 << type_size) - 1; } n->size = type_size / BITS_PER_UNIT; } break; default: return NULL_TREE; }; return verify_symbolic_number_p (n, stmt) ? source_expr1 : NULL; } /* Handle binary rhs. */ if (rhs_class == GIMPLE_BINARY_RHS) { struct symbolic_number n1, n2; tree source_expr2; if (code != BIT_IOR_EXPR) return NULL_TREE; if (TREE_CODE (rhs2) != SSA_NAME) return NULL_TREE; rhs2_stmt = SSA_NAME_DEF_STMT (rhs2); switch (code) { case BIT_IOR_EXPR: source_expr1 = find_bswap_1 (rhs1_stmt, &n1, limit - 1); if (!source_expr1) return NULL_TREE; source_expr2 = find_bswap_1 (rhs2_stmt, &n2, limit - 1); if (source_expr1 != source_expr2 || n1.size != n2.size) return NULL_TREE; n->size = n1.size; n->n = n1.n | n2.n; if (!verify_symbolic_number_p (n, stmt)) return NULL_TREE; break; default: return NULL_TREE; } return source_expr1; } return NULL_TREE; } /* Check if STMT completes a bswap implementation consisting of ORs, SHIFTs and ANDs. Return the source tree expression on which the byte swap is performed and NULL if no bswap was found. */ static tree find_bswap (gimple stmt) { /* The number which the find_bswap result should match in order to have a full byte swap. The number is shifted to the left according to the size of the symbolic number before using it. */ unsigned HOST_WIDEST_INT cmp = sizeof (HOST_WIDEST_INT) < 8 ? 0 : (unsigned HOST_WIDEST_INT)0x01020304 << 32 | 0x05060708; struct symbolic_number n; tree source_expr; int limit; /* The last parameter determines the depth search limit. It usually correlates directly to the number of bytes to be touched. We increase that number by three here in order to also cover signed -> unsigned converions of the src operand as can be seen in libgcc, and for initial shift/and operation of the src operand. */ limit = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (gimple_expr_type (stmt))); limit += 1 + (int) ceil_log2 ((unsigned HOST_WIDE_INT) limit); source_expr = find_bswap_1 (stmt, &n, limit); if (!source_expr) return NULL_TREE; /* Zero out the extra bits of N and CMP. */ if (n.size < (int)sizeof (HOST_WIDEST_INT)) { unsigned HOST_WIDEST_INT mask = ((unsigned HOST_WIDEST_INT)1 << (n.size * BITS_PER_UNIT)) - 1; n.n &= mask; cmp >>= (sizeof (HOST_WIDEST_INT) - n.size) * BITS_PER_UNIT; } /* A complete byte swap should make the symbolic number to start with the largest digit in the highest order byte. */ if (cmp != n.n) return NULL_TREE; return source_expr; } /* Find manual byte swap implementations and turn them into a bswap builtin invokation. */ static unsigned int execute_optimize_bswap (void) { basic_block bb; bool bswap32_p, bswap64_p; bool changed = false; tree bswap32_type = NULL_TREE, bswap64_type = NULL_TREE; if (BITS_PER_UNIT != 8) return 0; if (sizeof (HOST_WIDEST_INT) < 8) return 0; bswap32_p = (built_in_decls[BUILT_IN_BSWAP32] && optab_handler (bswap_optab, SImode) != CODE_FOR_nothing); bswap64_p = (built_in_decls[BUILT_IN_BSWAP64] && (optab_handler (bswap_optab, DImode) != CODE_FOR_nothing || (bswap32_p && word_mode == SImode))); if (!bswap32_p && !bswap64_p) return 0; /* Determine the argument type of the builtins. The code later on assumes that the return and argument type are the same. */ if (bswap32_p) { tree fndecl = built_in_decls[BUILT_IN_BSWAP32]; bswap32_type = TREE_VALUE (TYPE_ARG_TYPES (TREE_TYPE (fndecl))); } if (bswap64_p) { tree fndecl = built_in_decls[BUILT_IN_BSWAP64]; bswap64_type = TREE_VALUE (TYPE_ARG_TYPES (TREE_TYPE (fndecl))); } memset (&bswap_stats, 0, sizeof (bswap_stats)); FOR_EACH_BB (bb) { gimple_stmt_iterator gsi; /* We do a reverse scan for bswap patterns to make sure we get the widest match. As bswap pattern matching doesn't handle previously inserted smaller bswap replacements as sub- patterns, the wider variant wouldn't be detected. */ for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi); gsi_prev (&gsi)) { gimple stmt = gsi_stmt (gsi); tree bswap_src, bswap_type; tree bswap_tmp; tree fndecl = NULL_TREE; int type_size; gimple call; if (!is_gimple_assign (stmt) || gimple_assign_rhs_code (stmt) != BIT_IOR_EXPR) continue; type_size = TYPE_PRECISION (gimple_expr_type (stmt)); switch (type_size) { case 32: if (bswap32_p) { fndecl = built_in_decls[BUILT_IN_BSWAP32]; bswap_type = bswap32_type; } break; case 64: if (bswap64_p) { fndecl = built_in_decls[BUILT_IN_BSWAP64]; bswap_type = bswap64_type; } break; default: continue; } if (!fndecl) continue; bswap_src = find_bswap (stmt); if (!bswap_src) continue; changed = true; if (type_size == 32) bswap_stats.found_32bit++; else bswap_stats.found_64bit++; bswap_tmp = bswap_src; /* Convert the src expression if necessary. */ if (!useless_type_conversion_p (TREE_TYPE (bswap_tmp), bswap_type)) { gimple convert_stmt; bswap_tmp = create_tmp_var (bswap_type, "bswapsrc"); add_referenced_var (bswap_tmp); bswap_tmp = make_ssa_name (bswap_tmp, NULL); convert_stmt = gimple_build_assign_with_ops ( CONVERT_EXPR, bswap_tmp, bswap_src, NULL); gsi_insert_before (&gsi, convert_stmt, GSI_SAME_STMT); } call = gimple_build_call (fndecl, 1, bswap_tmp); bswap_tmp = gimple_assign_lhs (stmt); /* Convert the result if necessary. */ if (!useless_type_conversion_p (TREE_TYPE (bswap_tmp), bswap_type)) { gimple convert_stmt; bswap_tmp = create_tmp_var (bswap_type, "bswapdst"); add_referenced_var (bswap_tmp); bswap_tmp = make_ssa_name (bswap_tmp, NULL); convert_stmt = gimple_build_assign_with_ops ( CONVERT_EXPR, gimple_assign_lhs (stmt), bswap_tmp, NULL); gsi_insert_after (&gsi, convert_stmt, GSI_SAME_STMT); } gimple_call_set_lhs (call, bswap_tmp); if (dump_file) { fprintf (dump_file, "%d bit bswap implementation found at: ", (int)type_size); print_gimple_stmt (dump_file, stmt, 0, 0); } gsi_insert_after (&gsi, call, GSI_SAME_STMT); gsi_remove (&gsi, true); } } statistics_counter_event (cfun, "32-bit bswap implementations found", bswap_stats.found_32bit); statistics_counter_event (cfun, "64-bit bswap implementations found", bswap_stats.found_64bit); return (changed ? TODO_update_ssa | TODO_verify_ssa | TODO_verify_stmts : 0); } static bool gate_optimize_bswap (void) { return flag_expensive_optimizations && optimize; } struct gimple_opt_pass pass_optimize_bswap = { { GIMPLE_PASS, "bswap", /* name */ gate_optimize_bswap, /* gate */ execute_optimize_bswap, /* execute */ NULL, /* sub */ NULL, /* next */ 0, /* static_pass_number */ TV_NONE, /* tv_id */ PROP_ssa, /* properties_required */ 0, /* properties_provided */ 0, /* properties_destroyed */ 0, /* todo_flags_start */ 0 /* todo_flags_finish */ } }; /* Return true if RHS is a suitable operand for a widening multiplication. There are two cases: - RHS makes some value twice as wide. Store that value in *NEW_RHS_OUT if so, and store its type in *TYPE_OUT. - RHS is an integer constant. Store that value in *NEW_RHS_OUT if so, but leave *TYPE_OUT untouched. */ static bool is_widening_mult_rhs_p (tree rhs, tree *type_out, tree *new_rhs_out) { gimple stmt; tree type, type1, rhs1; enum tree_code rhs_code; if (TREE_CODE (rhs) == SSA_NAME) { type = TREE_TYPE (rhs); stmt = SSA_NAME_DEF_STMT (rhs); if (!is_gimple_assign (stmt)) return false; rhs_code = gimple_assign_rhs_code (stmt); if (TREE_CODE (type) == INTEGER_TYPE ? !CONVERT_EXPR_CODE_P (rhs_code) : rhs_code != FIXED_CONVERT_EXPR) return false; rhs1 = gimple_assign_rhs1 (stmt); type1 = TREE_TYPE (rhs1); if (TREE_CODE (type1) != TREE_CODE (type) || TYPE_PRECISION (type1) * 2 != TYPE_PRECISION (type)) return false; *new_rhs_out = rhs1; *type_out = type1; return true; } if (TREE_CODE (rhs) == INTEGER_CST) { *new_rhs_out = rhs; *type_out = NULL; return true; } return false; } /* Return true if STMT performs a widening multiplication. If so, store the unwidened types of the operands in *TYPE1_OUT and *TYPE2_OUT respectively. Also fill *RHS1_OUT and *RHS2_OUT such that converting those operands to types *TYPE1_OUT and *TYPE2_OUT would give the operands of the multiplication. */ static bool is_widening_mult_p (gimple stmt, tree *type1_out, tree *rhs1_out, tree *type2_out, tree *rhs2_out) { tree type; type = TREE_TYPE (gimple_assign_lhs (stmt)); if (TREE_CODE (type) != INTEGER_TYPE && TREE_CODE (type) != FIXED_POINT_TYPE) return false; if (!is_widening_mult_rhs_p (gimple_assign_rhs1 (stmt), type1_out, rhs1_out)) return false; if (!is_widening_mult_rhs_p (gimple_assign_rhs2 (stmt), type2_out, rhs2_out)) return false; if (*type1_out == NULL) { if (*type2_out == NULL || !int_fits_type_p (*rhs1_out, *type2_out)) return false; *type1_out = *type2_out; } if (*type2_out == NULL) { if (!int_fits_type_p (*rhs2_out, *type1_out)) return false; *type2_out = *type1_out; } return true; } /* Process a single gimple statement STMT, which has a MULT_EXPR as its rhs, and try to convert it into a WIDEN_MULT_EXPR. The return value is true iff we converted the statement. */ static bool convert_mult_to_widen (gimple stmt) { tree lhs, rhs1, rhs2, type, type1, type2; enum insn_code handler; lhs = gimple_assign_lhs (stmt); type = TREE_TYPE (lhs); if (TREE_CODE (type) != INTEGER_TYPE) return false; if (!is_widening_mult_p (stmt, &type1, &rhs1, &type2, &rhs2)) return false; if (TYPE_UNSIGNED (type1) && TYPE_UNSIGNED (type2)) handler = optab_handler (umul_widen_optab, TYPE_MODE (type)); else if (!TYPE_UNSIGNED (type1) && !TYPE_UNSIGNED (type2)) handler = optab_handler (smul_widen_optab, TYPE_MODE (type)); else handler = optab_handler (usmul_widen_optab, TYPE_MODE (type)); if (handler == CODE_FOR_nothing) return false; gimple_assign_set_rhs1 (stmt, fold_convert (type1, rhs1)); gimple_assign_set_rhs2 (stmt, fold_convert (type2, rhs2)); gimple_assign_set_rhs_code (stmt, WIDEN_MULT_EXPR); update_stmt (stmt); widen_mul_stats.widen_mults_inserted++; return true; } /* Process a single gimple statement STMT, which is found at the iterator GSI and has a either a PLUS_EXPR or a MINUS_EXPR as its rhs (given by CODE), and try to convert it into a WIDEN_MULT_PLUS_EXPR or a WIDEN_MULT_MINUS_EXPR. The return value is true iff we converted the statement. */ static bool convert_plusminus_to_widen (gimple_stmt_iterator *gsi, gimple stmt, enum tree_code code) { gimple rhs1_stmt = NULL, rhs2_stmt = NULL; tree type, type1, type2; tree lhs, rhs1, rhs2, mult_rhs1, mult_rhs2, add_rhs; enum tree_code rhs1_code = ERROR_MARK, rhs2_code = ERROR_MARK; optab this_optab; enum tree_code wmult_code; lhs = gimple_assign_lhs (stmt); type = TREE_TYPE (lhs); if (TREE_CODE (type) != INTEGER_TYPE && TREE_CODE (type) != FIXED_POINT_TYPE) return false; if (code == MINUS_EXPR) wmult_code = WIDEN_MULT_MINUS_EXPR; else wmult_code = WIDEN_MULT_PLUS_EXPR; rhs1 = gimple_assign_rhs1 (stmt); rhs2 = gimple_assign_rhs2 (stmt); if (TREE_CODE (rhs1) == SSA_NAME) { rhs1_stmt = SSA_NAME_DEF_STMT (rhs1); if (is_gimple_assign (rhs1_stmt)) rhs1_code = gimple_assign_rhs_code (rhs1_stmt); } else return false; if (TREE_CODE (rhs2) == SSA_NAME) { rhs2_stmt = SSA_NAME_DEF_STMT (rhs2); if (is_gimple_assign (rhs2_stmt)) rhs2_code = gimple_assign_rhs_code (rhs2_stmt); } else return false; if (code == PLUS_EXPR && rhs1_code == MULT_EXPR) { if (!is_widening_mult_p (rhs1_stmt, &type1, &mult_rhs1, &type2, &mult_rhs2)) return false; add_rhs = rhs2; } else if (rhs2_code == MULT_EXPR) { if (!is_widening_mult_p (rhs2_stmt, &type1, &mult_rhs1, &type2, &mult_rhs2)) return false; add_rhs = rhs1; } else if (code == PLUS_EXPR && rhs1_code == WIDEN_MULT_EXPR) { mult_rhs1 = gimple_assign_rhs1 (rhs1_stmt); mult_rhs2 = gimple_assign_rhs2 (rhs1_stmt); type1 = TREE_TYPE (mult_rhs1); type2 = TREE_TYPE (mult_rhs2); add_rhs = rhs2; } else if (rhs2_code == WIDEN_MULT_EXPR) { mult_rhs1 = gimple_assign_rhs1 (rhs2_stmt); mult_rhs2 = gimple_assign_rhs2 (rhs2_stmt); type1 = TREE_TYPE (mult_rhs1); type2 = TREE_TYPE (mult_rhs2); add_rhs = rhs1; } else return false; if (TYPE_UNSIGNED (type1) != TYPE_UNSIGNED (type2)) return false; /* Verify that the machine can perform a widening multiply accumulate in this mode/signedness combination, otherwise this transformation is likely to pessimize code. */ this_optab = optab_for_tree_code (wmult_code, type1, optab_default); if (optab_handler (this_optab, TYPE_MODE (type)) == CODE_FOR_nothing) return false; /* ??? May need some type verification here? */ gimple_assign_set_rhs_with_ops_1 (gsi, wmult_code, fold_convert (type1, mult_rhs1), fold_convert (type2, mult_rhs2), add_rhs); update_stmt (gsi_stmt (*gsi)); widen_mul_stats.maccs_inserted++; return true; } /* Combine the multiplication at MUL_STMT with operands MULOP1 and MULOP2 with uses in additions and subtractions to form fused multiply-add operations. Returns true if successful and MUL_STMT should be removed. */ static bool convert_mult_to_fma (gimple mul_stmt, tree op1, tree op2) { tree mul_result = gimple_get_lhs (mul_stmt); tree type = TREE_TYPE (mul_result); gimple use_stmt, neguse_stmt, fma_stmt; use_operand_p use_p; imm_use_iterator imm_iter; if (FLOAT_TYPE_P (type) && flag_fp_contract_mode == FP_CONTRACT_OFF) return false; /* We don't want to do bitfield reduction ops. */ if (INTEGRAL_TYPE_P (type) && (TYPE_PRECISION (type) != GET_MODE_PRECISION (TYPE_MODE (type)))) return false; /* If the target doesn't support it, don't generate it. We assume that if fma isn't available then fms, fnma or fnms are not either. */ if (optab_handler (fma_optab, TYPE_MODE (type)) == CODE_FOR_nothing) return false; /* Make sure that the multiplication statement becomes dead after the transformation, thus that all uses are transformed to FMAs. This means we assume that an FMA operation has the same cost as an addition. */ FOR_EACH_IMM_USE_FAST (use_p, imm_iter, mul_result) { enum tree_code use_code; tree result = mul_result; bool negate_p = false; use_stmt = USE_STMT (use_p); if (is_gimple_debug (use_stmt)) continue; /* For now restrict this operations to single basic blocks. In theory we would want to support sinking the multiplication in m = a*b; if () ma = m + c; else d = m; to form a fma in the then block and sink the multiplication to the else block. */ if (gimple_bb (use_stmt) != gimple_bb (mul_stmt)) return false; if (!is_gimple_assign (use_stmt)) return false; use_code = gimple_assign_rhs_code (use_stmt); /* A negate on the multiplication leads to FNMA. */ if (use_code == NEGATE_EXPR) { ssa_op_iter iter; use_operand_p usep; result = gimple_assign_lhs (use_stmt); /* Make sure the negate statement becomes dead with this single transformation. */ if (!single_imm_use (gimple_assign_lhs (use_stmt), &use_p, &neguse_stmt)) return false; /* Make sure the multiplication isn't also used on that stmt. */ FOR_EACH_PHI_OR_STMT_USE (usep, neguse_stmt, iter, SSA_OP_USE) if (USE_FROM_PTR (usep) == mul_result) return false; /* Re-validate. */ use_stmt = neguse_stmt; if (gimple_bb (use_stmt) != gimple_bb (mul_stmt)) return false; if (!is_gimple_assign (use_stmt)) return false; use_code = gimple_assign_rhs_code (use_stmt); negate_p = true; } switch (use_code) { case MINUS_EXPR: if (gimple_assign_rhs2 (use_stmt) == result) negate_p = !negate_p; break; case PLUS_EXPR: break; default: /* FMA can only be formed from PLUS and MINUS. */ return false; } /* We can't handle a * b + a * b. */ if (gimple_assign_rhs1 (use_stmt) == gimple_assign_rhs2 (use_stmt)) return false; /* While it is possible to validate whether or not the exact form that we've recognized is available in the backend, the assumption is that the transformation is never a loss. For instance, suppose the target only has the plain FMA pattern available. Consider a*b-c -> fma(a,b,-c): we've exchanged MUL+SUB for FMA+NEG, which is still two operations. Consider -(a*b)-c -> fma(-a,b,-c): we still have 3 operations, but in the FMA form the two NEGs are independant and could be run in parallel. */ } FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, mul_result) { gimple_stmt_iterator gsi = gsi_for_stmt (use_stmt); enum tree_code use_code; tree addop, mulop1 = op1, result = mul_result; bool negate_p = false; if (is_gimple_debug (use_stmt)) continue; use_code = gimple_assign_rhs_code (use_stmt); if (use_code == NEGATE_EXPR) { result = gimple_assign_lhs (use_stmt); single_imm_use (gimple_assign_lhs (use_stmt), &use_p, &neguse_stmt); gsi_remove (&gsi, true); release_defs (use_stmt); use_stmt = neguse_stmt; gsi = gsi_for_stmt (use_stmt); use_code = gimple_assign_rhs_code (use_stmt); negate_p = true; } if (gimple_assign_rhs1 (use_stmt) == result) { addop = gimple_assign_rhs2 (use_stmt); /* a * b - c -> a * b + (-c) */ if (gimple_assign_rhs_code (use_stmt) == MINUS_EXPR) addop = force_gimple_operand_gsi (&gsi, build1 (NEGATE_EXPR, type, addop), true, NULL_TREE, true, GSI_SAME_STMT); } else { addop = gimple_assign_rhs1 (use_stmt); /* a - b * c -> (-b) * c + a */ if (gimple_assign_rhs_code (use_stmt) == MINUS_EXPR) negate_p = !negate_p; } if (negate_p) mulop1 = force_gimple_operand_gsi (&gsi, build1 (NEGATE_EXPR, type, mulop1), true, NULL_TREE, true, GSI_SAME_STMT); fma_stmt = gimple_build_assign_with_ops3 (FMA_EXPR, gimple_assign_lhs (use_stmt), mulop1, op2, addop); gsi_replace (&gsi, fma_stmt, true); widen_mul_stats.fmas_inserted++; } return true; } /* Find integer multiplications where the operands are extended from smaller types, and replace the MULT_EXPR with a WIDEN_MULT_EXPR where appropriate. */ static unsigned int execute_optimize_widening_mul (void) { basic_block bb; bool cfg_changed = false; memset (&widen_mul_stats, 0, sizeof (widen_mul_stats)); FOR_EACH_BB (bb) { gimple_stmt_iterator gsi; for (gsi = gsi_after_labels (bb); !gsi_end_p (gsi);) { gimple stmt = gsi_stmt (gsi); enum tree_code code; if (is_gimple_assign (stmt)) { code = gimple_assign_rhs_code (stmt); switch (code) { case MULT_EXPR: if (!convert_mult_to_widen (stmt) && convert_mult_to_fma (stmt, gimple_assign_rhs1 (stmt), gimple_assign_rhs2 (stmt))) { gsi_remove (&gsi, true); release_defs (stmt); continue; } break; case PLUS_EXPR: case MINUS_EXPR: convert_plusminus_to_widen (&gsi, stmt, code); break; default:; } } else if (is_gimple_call (stmt) && gimple_call_lhs (stmt)) { tree fndecl = gimple_call_fndecl (stmt); if (fndecl && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL) { switch (DECL_FUNCTION_CODE (fndecl)) { case BUILT_IN_POWF: case BUILT_IN_POW: case BUILT_IN_POWL: if (TREE_CODE (gimple_call_arg (stmt, 1)) == REAL_CST && REAL_VALUES_EQUAL (TREE_REAL_CST (gimple_call_arg (stmt, 1)), dconst2) && convert_mult_to_fma (stmt, gimple_call_arg (stmt, 0), gimple_call_arg (stmt, 0))) { unlink_stmt_vdef (stmt); gsi_remove (&gsi, true); release_defs (stmt); if (gimple_purge_dead_eh_edges (bb)) cfg_changed = true; continue; } break; default:; } } } gsi_next (&gsi); } } statistics_counter_event (cfun, "widening multiplications inserted", widen_mul_stats.widen_mults_inserted); statistics_counter_event (cfun, "widening maccs inserted", widen_mul_stats.maccs_inserted); statistics_counter_event (cfun, "fused multiply-adds inserted", widen_mul_stats.fmas_inserted); return cfg_changed ? TODO_cleanup_cfg : 0; } static bool gate_optimize_widening_mul (void) { return flag_expensive_optimizations && optimize; } struct gimple_opt_pass pass_optimize_widening_mul = { { GIMPLE_PASS, "widening_mul", /* name */ gate_optimize_widening_mul, /* gate */ execute_optimize_widening_mul, /* execute */ NULL, /* sub */ NULL, /* next */ 0, /* static_pass_number */ TV_NONE, /* tv_id */ PROP_ssa, /* properties_required */ 0, /* properties_provided */ 0, /* properties_destroyed */ 0, /* todo_flags_start */ TODO_verify_ssa | TODO_verify_stmts | TODO_update_ssa /* todo_flags_finish */ } };