1 /* Global, SSA-based optimizations using mathematical identities.
2 Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011
3 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by the
9 Free Software Foundation; either version 3, or (at your option) any
12 GCC is distributed in the hope that it will be useful, but WITHOUT
13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
21 /* Currently, the only mini-pass in this file tries to CSE reciprocal
22 operations. These are common in sequences such as this one:
24 modulus = sqrt(x*x + y*y + z*z);
29 that can be optimized to
31 modulus = sqrt(x*x + y*y + z*z);
32 rmodulus = 1.0 / modulus;
37 We do this for loop invariant divisors, and with this pass whenever
38 we notice that a division has the same divisor multiple times.
40 Of course, like in PRE, we don't insert a division if a dominator
41 already has one. However, this cannot be done as an extension of
42 PRE for several reasons.
44 First of all, with some experiments it was found out that the
45 transformation is not always useful if there are only two divisions
46 hy the same divisor. This is probably because modern processors
47 can pipeline the divisions; on older, in-order processors it should
48 still be effective to optimize two divisions by the same number.
49 We make this a param, and it shall be called N in the remainder of
52 Second, if trapping math is active, we have less freedom on where
53 to insert divisions: we can only do so in basic blocks that already
54 contain one. (If divisions don't trap, instead, we can insert
55 divisions elsewhere, which will be in blocks that are common dominators
56 of those that have the division).
58 We really don't want to compute the reciprocal unless a division will
59 be found. To do this, we won't insert the division in a basic block
60 that has less than N divisions *post-dominating* it.
62 The algorithm constructs a subset of the dominator tree, holding the
63 blocks containing the divisions and the common dominators to them,
64 and walk it twice. The first walk is in post-order, and it annotates
65 each block with the number of divisions that post-dominate it: this
66 gives information on where divisions can be inserted profitably.
67 The second walk is in pre-order, and it inserts divisions as explained
68 above, and replaces divisions by multiplications.
70 In the best case, the cost of the pass is O(n_statements). In the
71 worst-case, the cost is due to creating the dominator tree subset,
72 with a cost of O(n_basic_blocks ^ 2); however this can only happen
73 for n_statements / n_basic_blocks statements. So, the amortized cost
74 of creating the dominator tree subset is O(n_basic_blocks) and the
75 worst-case cost of the pass is O(n_statements * n_basic_blocks).
77 More practically, the cost will be small because there are few
78 divisions, and they tend to be in the same basic block, so insert_bb
79 is called very few times.
81 If we did this using domwalk.c, an efficient implementation would have
82 to work on all the variables in a single pass, because we could not
83 work on just a subset of the dominator tree, as we do now, and the
84 cost would also be something like O(n_statements * n_basic_blocks).
85 The data structures would be more complex in order to work on all the
86 variables in a single pass. */
90 #include "coretypes.h"
94 #include "tree-flow.h"
96 #include "tree-pass.h"
97 #include "alloc-pool.h"
98 #include "basic-block.h"
100 #include "gimple-pretty-print.h"
102 /* FIXME: RTL headers have to be included here for optabs. */
103 #include "rtl.h" /* Because optabs.h wants enum rtx_code. */
104 #include "expr.h" /* Because optabs.h wants sepops. */
107 /* This structure represents one basic block that either computes a
108 division, or is a common dominator for basic block that compute a
111 /* The basic block represented by this structure. */
114 /* If non-NULL, the SSA_NAME holding the definition for a reciprocal
118 /* If non-NULL, the GIMPLE_ASSIGN for a reciprocal computation that
119 was inserted in BB. */
120 gimple recip_def_stmt;
122 /* Pointer to a list of "struct occurrence"s for blocks dominated
124 struct occurrence *children;
126 /* Pointer to the next "struct occurrence"s in the list of blocks
127 sharing a common dominator. */
128 struct occurrence *next;
130 /* The number of divisions that are in BB before compute_merit. The
131 number of divisions that are in BB or post-dominate it after
135 /* True if the basic block has a division, false if it is a common
136 dominator for basic blocks that do. If it is false and trapping
137 math is active, BB is not a candidate for inserting a reciprocal. */
138 bool bb_has_division;
143 /* Number of 1.0/X ops inserted. */
146 /* Number of 1.0/FUNC ops inserted. */
152 /* Number of cexpi calls inserted. */
158 /* Number of hand-written 32-bit bswaps found. */
161 /* Number of hand-written 64-bit bswaps found. */
167 /* Number of widening multiplication ops inserted. */
168 int widen_mults_inserted;
170 /* Number of integer multiply-and-accumulate ops inserted. */
173 /* Number of fp fused multiply-add ops inserted. */
177 /* The instance of "struct occurrence" representing the highest
178 interesting block in the dominator tree. */
179 static struct occurrence *occ_head;
181 /* Allocation pool for getting instances of "struct occurrence". */
182 static alloc_pool occ_pool;
186 /* Allocate and return a new struct occurrence for basic block BB, and
187 whose children list is headed by CHILDREN. */
188 static struct occurrence *
189 occ_new (basic_block bb, struct occurrence *children)
191 struct occurrence *occ;
193 bb->aux = occ = (struct occurrence *) pool_alloc (occ_pool);
194 memset (occ, 0, sizeof (struct occurrence));
197 occ->children = children;
202 /* Insert NEW_OCC into our subset of the dominator tree. P_HEAD points to a
203 list of "struct occurrence"s, one per basic block, having IDOM as
204 their common dominator.
206 We try to insert NEW_OCC as deep as possible in the tree, and we also
207 insert any other block that is a common dominator for BB and one
208 block already in the tree. */
211 insert_bb (struct occurrence *new_occ, basic_block idom,
212 struct occurrence **p_head)
214 struct occurrence *occ, **p_occ;
216 for (p_occ = p_head; (occ = *p_occ) != NULL; )
218 basic_block bb = new_occ->bb, occ_bb = occ->bb;
219 basic_block dom = nearest_common_dominator (CDI_DOMINATORS, occ_bb, bb);
222 /* BB dominates OCC_BB. OCC becomes NEW_OCC's child: remove OCC
225 occ->next = new_occ->children;
226 new_occ->children = occ;
228 /* Try the next block (it may as well be dominated by BB). */
231 else if (dom == occ_bb)
233 /* OCC_BB dominates BB. Tail recurse to look deeper. */
234 insert_bb (new_occ, dom, &occ->children);
238 else if (dom != idom)
240 gcc_assert (!dom->aux);
242 /* There is a dominator between IDOM and BB, add it and make
243 two children out of NEW_OCC and OCC. First, remove OCC from
249 /* None of the previous blocks has DOM as a dominator: if we tail
250 recursed, we would reexamine them uselessly. Just switch BB with
251 DOM, and go on looking for blocks dominated by DOM. */
252 new_occ = occ_new (dom, new_occ);
257 /* Nothing special, go on with the next element. */
262 /* No place was found as a child of IDOM. Make BB a sibling of IDOM. */
263 new_occ->next = *p_head;
267 /* Register that we found a division in BB. */
270 register_division_in (basic_block bb)
272 struct occurrence *occ;
274 occ = (struct occurrence *) bb->aux;
277 occ = occ_new (bb, NULL);
278 insert_bb (occ, ENTRY_BLOCK_PTR, &occ_head);
281 occ->bb_has_division = true;
282 occ->num_divisions++;
286 /* Compute the number of divisions that postdominate each block in OCC and
290 compute_merit (struct occurrence *occ)
292 struct occurrence *occ_child;
293 basic_block dom = occ->bb;
295 for (occ_child = occ->children; occ_child; occ_child = occ_child->next)
298 if (occ_child->children)
299 compute_merit (occ_child);
302 bb = single_noncomplex_succ (dom);
306 if (dominated_by_p (CDI_POST_DOMINATORS, bb, occ_child->bb))
307 occ->num_divisions += occ_child->num_divisions;
312 /* Return whether USE_STMT is a floating-point division by DEF. */
314 is_division_by (gimple use_stmt, tree def)
316 return is_gimple_assign (use_stmt)
317 && gimple_assign_rhs_code (use_stmt) == RDIV_EXPR
318 && gimple_assign_rhs2 (use_stmt) == def
319 /* Do not recognize x / x as valid division, as we are getting
320 confused later by replacing all immediate uses x in such
322 && gimple_assign_rhs1 (use_stmt) != def;
325 /* Walk the subset of the dominator tree rooted at OCC, setting the
326 RECIP_DEF field to a definition of 1.0 / DEF that can be used in
327 the given basic block. The field may be left NULL, of course,
328 if it is not possible or profitable to do the optimization.
330 DEF_BSI is an iterator pointing at the statement defining DEF.
331 If RECIP_DEF is set, a dominator already has a computation that can
335 insert_reciprocals (gimple_stmt_iterator *def_gsi, struct occurrence *occ,
336 tree def, tree recip_def, int threshold)
340 gimple_stmt_iterator gsi;
341 struct occurrence *occ_child;
344 && (occ->bb_has_division || !flag_trapping_math)
345 && occ->num_divisions >= threshold)
347 /* Make a variable with the replacement and substitute it. */
348 type = TREE_TYPE (def);
349 recip_def = make_rename_temp (type, "reciptmp");
350 new_stmt = gimple_build_assign_with_ops (RDIV_EXPR, recip_def,
351 build_one_cst (type), def);
353 if (occ->bb_has_division)
355 /* Case 1: insert before an existing division. */
356 gsi = gsi_after_labels (occ->bb);
357 while (!gsi_end_p (gsi) && !is_division_by (gsi_stmt (gsi), def))
360 gsi_insert_before (&gsi, new_stmt, GSI_SAME_STMT);
362 else if (def_gsi && occ->bb == def_gsi->bb)
364 /* Case 2: insert right after the definition. Note that this will
365 never happen if the definition statement can throw, because in
366 that case the sole successor of the statement's basic block will
367 dominate all the uses as well. */
368 gsi_insert_after (def_gsi, new_stmt, GSI_NEW_STMT);
372 /* Case 3: insert in a basic block not containing defs/uses. */
373 gsi = gsi_after_labels (occ->bb);
374 gsi_insert_before (&gsi, new_stmt, GSI_SAME_STMT);
377 reciprocal_stats.rdivs_inserted++;
379 occ->recip_def_stmt = new_stmt;
382 occ->recip_def = recip_def;
383 for (occ_child = occ->children; occ_child; occ_child = occ_child->next)
384 insert_reciprocals (def_gsi, occ_child, def, recip_def, threshold);
388 /* Replace the division at USE_P with a multiplication by the reciprocal, if
392 replace_reciprocal (use_operand_p use_p)
394 gimple use_stmt = USE_STMT (use_p);
395 basic_block bb = gimple_bb (use_stmt);
396 struct occurrence *occ = (struct occurrence *) bb->aux;
398 if (optimize_bb_for_speed_p (bb)
399 && occ->recip_def && use_stmt != occ->recip_def_stmt)
401 gimple_assign_set_rhs_code (use_stmt, MULT_EXPR);
402 SET_USE (use_p, occ->recip_def);
403 fold_stmt_inplace (use_stmt);
404 update_stmt (use_stmt);
409 /* Free OCC and return one more "struct occurrence" to be freed. */
411 static struct occurrence *
412 free_bb (struct occurrence *occ)
414 struct occurrence *child, *next;
416 /* First get the two pointers hanging off OCC. */
418 child = occ->children;
420 pool_free (occ_pool, occ);
422 /* Now ensure that we don't recurse unless it is necessary. */
428 next = free_bb (next);
435 /* Look for floating-point divisions among DEF's uses, and try to
436 replace them by multiplications with the reciprocal. Add
437 as many statements computing the reciprocal as needed.
439 DEF must be a GIMPLE register of a floating-point type. */
442 execute_cse_reciprocals_1 (gimple_stmt_iterator *def_gsi, tree def)
445 imm_use_iterator use_iter;
446 struct occurrence *occ;
447 int count = 0, threshold;
449 gcc_assert (FLOAT_TYPE_P (TREE_TYPE (def)) && is_gimple_reg (def));
451 FOR_EACH_IMM_USE_FAST (use_p, use_iter, def)
453 gimple use_stmt = USE_STMT (use_p);
454 if (is_division_by (use_stmt, def))
456 register_division_in (gimple_bb (use_stmt));
461 /* Do the expensive part only if we can hope to optimize something. */
462 threshold = targetm.min_divisions_for_recip_mul (TYPE_MODE (TREE_TYPE (def)));
463 if (count >= threshold)
466 for (occ = occ_head; occ; occ = occ->next)
469 insert_reciprocals (def_gsi, occ, def, NULL, threshold);
472 FOR_EACH_IMM_USE_STMT (use_stmt, use_iter, def)
474 if (is_division_by (use_stmt, def))
476 FOR_EACH_IMM_USE_ON_STMT (use_p, use_iter)
477 replace_reciprocal (use_p);
482 for (occ = occ_head; occ; )
489 gate_cse_reciprocals (void)
491 return optimize && flag_reciprocal_math;
494 /* Go through all the floating-point SSA_NAMEs, and call
495 execute_cse_reciprocals_1 on each of them. */
497 execute_cse_reciprocals (void)
502 occ_pool = create_alloc_pool ("dominators for recip",
503 sizeof (struct occurrence),
504 n_basic_blocks / 3 + 1);
506 memset (&reciprocal_stats, 0, sizeof (reciprocal_stats));
507 calculate_dominance_info (CDI_DOMINATORS);
508 calculate_dominance_info (CDI_POST_DOMINATORS);
510 #ifdef ENABLE_CHECKING
512 gcc_assert (!bb->aux);
515 for (arg = DECL_ARGUMENTS (cfun->decl); arg; arg = DECL_CHAIN (arg))
516 if (gimple_default_def (cfun, arg)
517 && FLOAT_TYPE_P (TREE_TYPE (arg))
518 && is_gimple_reg (arg))
519 execute_cse_reciprocals_1 (NULL, gimple_default_def (cfun, arg));
523 gimple_stmt_iterator gsi;
527 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
529 phi = gsi_stmt (gsi);
530 def = PHI_RESULT (phi);
531 if (FLOAT_TYPE_P (TREE_TYPE (def))
532 && is_gimple_reg (def))
533 execute_cse_reciprocals_1 (NULL, def);
536 for (gsi = gsi_after_labels (bb); !gsi_end_p (gsi); gsi_next (&gsi))
538 gimple stmt = gsi_stmt (gsi);
540 if (gimple_has_lhs (stmt)
541 && (def = SINGLE_SSA_TREE_OPERAND (stmt, SSA_OP_DEF)) != NULL
542 && FLOAT_TYPE_P (TREE_TYPE (def))
543 && TREE_CODE (def) == SSA_NAME)
544 execute_cse_reciprocals_1 (&gsi, def);
547 if (optimize_bb_for_size_p (bb))
550 /* Scan for a/func(b) and convert it to reciprocal a*rfunc(b). */
551 for (gsi = gsi_after_labels (bb); !gsi_end_p (gsi); gsi_next (&gsi))
553 gimple stmt = gsi_stmt (gsi);
556 if (is_gimple_assign (stmt)
557 && gimple_assign_rhs_code (stmt) == RDIV_EXPR)
559 tree arg1 = gimple_assign_rhs2 (stmt);
562 if (TREE_CODE (arg1) != SSA_NAME)
565 stmt1 = SSA_NAME_DEF_STMT (arg1);
567 if (is_gimple_call (stmt1)
568 && gimple_call_lhs (stmt1)
569 && (fndecl = gimple_call_fndecl (stmt1))
570 && (DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL
571 || DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_MD))
573 enum built_in_function code;
578 code = DECL_FUNCTION_CODE (fndecl);
579 md_code = DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_MD;
581 fndecl = targetm.builtin_reciprocal (code, md_code, false);
585 /* Check that all uses of the SSA name are divisions,
586 otherwise replacing the defining statement will do
589 FOR_EACH_IMM_USE_FAST (use_p, ui, arg1)
591 gimple stmt2 = USE_STMT (use_p);
592 if (is_gimple_debug (stmt2))
594 if (!is_gimple_assign (stmt2)
595 || gimple_assign_rhs_code (stmt2) != RDIV_EXPR
596 || gimple_assign_rhs1 (stmt2) == arg1
597 || gimple_assign_rhs2 (stmt2) != arg1)
606 gimple_replace_lhs (stmt1, arg1);
607 gimple_call_set_fndecl (stmt1, fndecl);
609 reciprocal_stats.rfuncs_inserted++;
611 FOR_EACH_IMM_USE_STMT (stmt, ui, arg1)
613 gimple_assign_set_rhs_code (stmt, MULT_EXPR);
614 fold_stmt_inplace (stmt);
622 statistics_counter_event (cfun, "reciprocal divs inserted",
623 reciprocal_stats.rdivs_inserted);
624 statistics_counter_event (cfun, "reciprocal functions inserted",
625 reciprocal_stats.rfuncs_inserted);
627 free_dominance_info (CDI_DOMINATORS);
628 free_dominance_info (CDI_POST_DOMINATORS);
629 free_alloc_pool (occ_pool);
633 struct gimple_opt_pass pass_cse_reciprocals =
638 gate_cse_reciprocals, /* gate */
639 execute_cse_reciprocals, /* execute */
642 0, /* static_pass_number */
644 PROP_ssa, /* properties_required */
645 0, /* properties_provided */
646 0, /* properties_destroyed */
647 0, /* todo_flags_start */
648 TODO_dump_func | TODO_update_ssa | TODO_verify_ssa
649 | TODO_verify_stmts /* todo_flags_finish */
653 /* Records an occurrence at statement USE_STMT in the vector of trees
654 STMTS if it is dominated by *TOP_BB or dominates it or this basic block
655 is not yet initialized. Returns true if the occurrence was pushed on
656 the vector. Adjusts *TOP_BB to be the basic block dominating all
657 statements in the vector. */
660 maybe_record_sincos (VEC(gimple, heap) **stmts,
661 basic_block *top_bb, gimple use_stmt)
663 basic_block use_bb = gimple_bb (use_stmt);
665 && (*top_bb == use_bb
666 || dominated_by_p (CDI_DOMINATORS, use_bb, *top_bb)))
667 VEC_safe_push (gimple, heap, *stmts, use_stmt);
669 || dominated_by_p (CDI_DOMINATORS, *top_bb, use_bb))
671 VEC_safe_push (gimple, heap, *stmts, use_stmt);
680 /* Look for sin, cos and cexpi calls with the same argument NAME and
681 create a single call to cexpi CSEing the result in this case.
682 We first walk over all immediate uses of the argument collecting
683 statements that we can CSE in a vector and in a second pass replace
684 the statement rhs with a REALPART or IMAGPART expression on the
685 result of the cexpi call we insert before the use statement that
686 dominates all other candidates. */
689 execute_cse_sincos_1 (tree name)
691 gimple_stmt_iterator gsi;
692 imm_use_iterator use_iter;
693 tree fndecl, res, type;
694 gimple def_stmt, use_stmt, stmt;
695 int seen_cos = 0, seen_sin = 0, seen_cexpi = 0;
696 VEC(gimple, heap) *stmts = NULL;
697 basic_block top_bb = NULL;
699 bool cfg_changed = false;
701 type = TREE_TYPE (name);
702 FOR_EACH_IMM_USE_STMT (use_stmt, use_iter, name)
704 if (gimple_code (use_stmt) != GIMPLE_CALL
705 || !gimple_call_lhs (use_stmt)
706 || !(fndecl = gimple_call_fndecl (use_stmt))
707 || DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_NORMAL)
710 switch (DECL_FUNCTION_CODE (fndecl))
712 CASE_FLT_FN (BUILT_IN_COS):
713 seen_cos |= maybe_record_sincos (&stmts, &top_bb, use_stmt) ? 1 : 0;
716 CASE_FLT_FN (BUILT_IN_SIN):
717 seen_sin |= maybe_record_sincos (&stmts, &top_bb, use_stmt) ? 1 : 0;
720 CASE_FLT_FN (BUILT_IN_CEXPI):
721 seen_cexpi |= maybe_record_sincos (&stmts, &top_bb, use_stmt) ? 1 : 0;
728 if (seen_cos + seen_sin + seen_cexpi <= 1)
730 VEC_free(gimple, heap, stmts);
734 /* Simply insert cexpi at the beginning of top_bb but not earlier than
735 the name def statement. */
736 fndecl = mathfn_built_in (type, BUILT_IN_CEXPI);
739 res = create_tmp_reg (TREE_TYPE (TREE_TYPE (fndecl)), "sincostmp");
740 stmt = gimple_build_call (fndecl, 1, name);
741 res = make_ssa_name (res, stmt);
742 gimple_call_set_lhs (stmt, res);
744 def_stmt = SSA_NAME_DEF_STMT (name);
745 if (!SSA_NAME_IS_DEFAULT_DEF (name)
746 && gimple_code (def_stmt) != GIMPLE_PHI
747 && gimple_bb (def_stmt) == top_bb)
749 gsi = gsi_for_stmt (def_stmt);
750 gsi_insert_after (&gsi, stmt, GSI_SAME_STMT);
754 gsi = gsi_after_labels (top_bb);
755 gsi_insert_before (&gsi, stmt, GSI_SAME_STMT);
758 sincos_stats.inserted++;
760 /* And adjust the recorded old call sites. */
761 for (i = 0; VEC_iterate(gimple, stmts, i, use_stmt); ++i)
764 fndecl = gimple_call_fndecl (use_stmt);
766 switch (DECL_FUNCTION_CODE (fndecl))
768 CASE_FLT_FN (BUILT_IN_COS):
769 rhs = fold_build1 (REALPART_EXPR, type, res);
772 CASE_FLT_FN (BUILT_IN_SIN):
773 rhs = fold_build1 (IMAGPART_EXPR, type, res);
776 CASE_FLT_FN (BUILT_IN_CEXPI):
784 /* Replace call with a copy. */
785 stmt = gimple_build_assign (gimple_call_lhs (use_stmt), rhs);
787 gsi = gsi_for_stmt (use_stmt);
788 gsi_replace (&gsi, stmt, true);
789 if (gimple_purge_dead_eh_edges (gimple_bb (stmt)))
793 VEC_free(gimple, heap, stmts);
798 /* To evaluate powi(x,n), the floating point value x raised to the
799 constant integer exponent n, we use a hybrid algorithm that
800 combines the "window method" with look-up tables. For an
801 introduction to exponentiation algorithms and "addition chains",
802 see section 4.6.3, "Evaluation of Powers" of Donald E. Knuth,
803 "Seminumerical Algorithms", Vol. 2, "The Art of Computer Programming",
804 3rd Edition, 1998, and Daniel M. Gordon, "A Survey of Fast Exponentiation
805 Methods", Journal of Algorithms, Vol. 27, pp. 129-146, 1998. */
807 /* Provide a default value for POWI_MAX_MULTS, the maximum number of
808 multiplications to inline before calling the system library's pow
809 function. powi(x,n) requires at worst 2*bits(n)-2 multiplications,
810 so this default never requires calling pow, powf or powl. */
812 #ifndef POWI_MAX_MULTS
813 #define POWI_MAX_MULTS (2*HOST_BITS_PER_WIDE_INT-2)
816 /* The size of the "optimal power tree" lookup table. All
817 exponents less than this value are simply looked up in the
818 powi_table below. This threshold is also used to size the
819 cache of pseudo registers that hold intermediate results. */
820 #define POWI_TABLE_SIZE 256
822 /* The size, in bits of the window, used in the "window method"
823 exponentiation algorithm. This is equivalent to a radix of
824 (1<<POWI_WINDOW_SIZE) in the corresponding "m-ary method". */
825 #define POWI_WINDOW_SIZE 3
827 /* The following table is an efficient representation of an
828 "optimal power tree". For each value, i, the corresponding
829 value, j, in the table states than an optimal evaluation
830 sequence for calculating pow(x,i) can be found by evaluating
831 pow(x,j)*pow(x,i-j). An optimal power tree for the first
832 100 integers is given in Knuth's "Seminumerical algorithms". */
834 static const unsigned char powi_table[POWI_TABLE_SIZE] =
836 0, 1, 1, 2, 2, 3, 3, 4, /* 0 - 7 */
837 4, 6, 5, 6, 6, 10, 7, 9, /* 8 - 15 */
838 8, 16, 9, 16, 10, 12, 11, 13, /* 16 - 23 */
839 12, 17, 13, 18, 14, 24, 15, 26, /* 24 - 31 */
840 16, 17, 17, 19, 18, 33, 19, 26, /* 32 - 39 */
841 20, 25, 21, 40, 22, 27, 23, 44, /* 40 - 47 */
842 24, 32, 25, 34, 26, 29, 27, 44, /* 48 - 55 */
843 28, 31, 29, 34, 30, 60, 31, 36, /* 56 - 63 */
844 32, 64, 33, 34, 34, 46, 35, 37, /* 64 - 71 */
845 36, 65, 37, 50, 38, 48, 39, 69, /* 72 - 79 */
846 40, 49, 41, 43, 42, 51, 43, 58, /* 80 - 87 */
847 44, 64, 45, 47, 46, 59, 47, 76, /* 88 - 95 */
848 48, 65, 49, 66, 50, 67, 51, 66, /* 96 - 103 */
849 52, 70, 53, 74, 54, 104, 55, 74, /* 104 - 111 */
850 56, 64, 57, 69, 58, 78, 59, 68, /* 112 - 119 */
851 60, 61, 61, 80, 62, 75, 63, 68, /* 120 - 127 */
852 64, 65, 65, 128, 66, 129, 67, 90, /* 128 - 135 */
853 68, 73, 69, 131, 70, 94, 71, 88, /* 136 - 143 */
854 72, 128, 73, 98, 74, 132, 75, 121, /* 144 - 151 */
855 76, 102, 77, 124, 78, 132, 79, 106, /* 152 - 159 */
856 80, 97, 81, 160, 82, 99, 83, 134, /* 160 - 167 */
857 84, 86, 85, 95, 86, 160, 87, 100, /* 168 - 175 */
858 88, 113, 89, 98, 90, 107, 91, 122, /* 176 - 183 */
859 92, 111, 93, 102, 94, 126, 95, 150, /* 184 - 191 */
860 96, 128, 97, 130, 98, 133, 99, 195, /* 192 - 199 */
861 100, 128, 101, 123, 102, 164, 103, 138, /* 200 - 207 */
862 104, 145, 105, 146, 106, 109, 107, 149, /* 208 - 215 */
863 108, 200, 109, 146, 110, 170, 111, 157, /* 216 - 223 */
864 112, 128, 113, 130, 114, 182, 115, 132, /* 224 - 231 */
865 116, 200, 117, 132, 118, 158, 119, 206, /* 232 - 239 */
866 120, 240, 121, 162, 122, 147, 123, 152, /* 240 - 247 */
867 124, 166, 125, 214, 126, 138, 127, 153, /* 248 - 255 */
871 /* Return the number of multiplications required to calculate
872 powi(x,n) where n is less than POWI_TABLE_SIZE. This is a
873 subroutine of powi_cost. CACHE is an array indicating
874 which exponents have already been calculated. */
877 powi_lookup_cost (unsigned HOST_WIDE_INT n, bool *cache)
879 /* If we've already calculated this exponent, then this evaluation
880 doesn't require any additional multiplications. */
885 return powi_lookup_cost (n - powi_table[n], cache)
886 + powi_lookup_cost (powi_table[n], cache) + 1;
889 /* Return the number of multiplications required to calculate
890 powi(x,n) for an arbitrary x, given the exponent N. This
891 function needs to be kept in sync with powi_as_mults below. */
894 powi_cost (HOST_WIDE_INT n)
896 bool cache[POWI_TABLE_SIZE];
897 unsigned HOST_WIDE_INT digit;
898 unsigned HOST_WIDE_INT val;
904 /* Ignore the reciprocal when calculating the cost. */
905 val = (n < 0) ? -n : n;
907 /* Initialize the exponent cache. */
908 memset (cache, 0, POWI_TABLE_SIZE * sizeof (bool));
913 while (val >= POWI_TABLE_SIZE)
917 digit = val & ((1 << POWI_WINDOW_SIZE) - 1);
918 result += powi_lookup_cost (digit, cache)
919 + POWI_WINDOW_SIZE + 1;
920 val >>= POWI_WINDOW_SIZE;
929 return result + powi_lookup_cost (val, cache);
932 /* Recursive subroutine of powi_as_mults. This function takes the
933 array, CACHE, of already calculated exponents and an exponent N and
934 returns a tree that corresponds to CACHE[1]**N, with type TYPE. */
937 powi_as_mults_1 (gimple_stmt_iterator *gsi, location_t loc, tree type,
938 HOST_WIDE_INT n, tree *cache, tree target)
940 tree op0, op1, ssa_target;
941 unsigned HOST_WIDE_INT digit;
944 if (n < POWI_TABLE_SIZE && cache[n])
947 ssa_target = make_ssa_name (target, NULL);
949 if (n < POWI_TABLE_SIZE)
951 cache[n] = ssa_target;
952 op0 = powi_as_mults_1 (gsi, loc, type, n - powi_table[n], cache, target);
953 op1 = powi_as_mults_1 (gsi, loc, type, powi_table[n], cache, target);
957 digit = n & ((1 << POWI_WINDOW_SIZE) - 1);
958 op0 = powi_as_mults_1 (gsi, loc, type, n - digit, cache, target);
959 op1 = powi_as_mults_1 (gsi, loc, type, digit, cache, target);
963 op0 = powi_as_mults_1 (gsi, loc, type, n >> 1, cache, target);
967 mult_stmt = gimple_build_assign_with_ops (MULT_EXPR, ssa_target, op0, op1);
968 gsi_insert_before (gsi, mult_stmt, GSI_SAME_STMT);
973 /* Convert ARG0**N to a tree of multiplications of ARG0 with itself.
974 This function needs to be kept in sync with powi_cost above. */
977 powi_as_mults (gimple_stmt_iterator *gsi, location_t loc,
978 tree arg0, HOST_WIDE_INT n)
980 tree cache[POWI_TABLE_SIZE], result, type = TREE_TYPE (arg0), target;
984 return build_real (type, dconst1);
986 memset (cache, 0, sizeof (cache));
989 target = create_tmp_var (type, "powmult");
990 add_referenced_var (target);
992 result = powi_as_mults_1 (gsi, loc, type, (n < 0) ? -n : n, cache, target);
997 /* If the original exponent was negative, reciprocate the result. */
998 target = make_ssa_name (target, NULL);
999 div_stmt = gimple_build_assign_with_ops (RDIV_EXPR, target,
1000 build_real (type, dconst1),
1002 gsi_insert_before (gsi, div_stmt, GSI_SAME_STMT);
1007 /* ARG0 and N are the two arguments to a powi builtin in GSI with
1008 location info LOC. If the arguments are appropriate, create an
1009 equivalent sequence of statements prior to GSI using an optimal
1010 number of multiplications, and return an expession holding the
1014 gimple_expand_builtin_powi (gimple_stmt_iterator *gsi, location_t loc,
1015 tree arg0, HOST_WIDE_INT n)
1017 /* Avoid largest negative number. */
1019 && ((n >= -1 && n <= 2)
1020 || (optimize_function_for_speed_p (cfun)
1021 && powi_cost (n) <= POWI_MAX_MULTS)))
1022 return powi_as_mults (gsi, loc, arg0, n);
1027 /* ARG0 and ARG1 are the two arguments to a pow builtin call in GSI
1028 with location info LOC. If possible, create an equivalent and
1029 less expensive sequence of statements prior to GSI, and return an
1030 expession holding the result. */
1033 gimple_expand_builtin_pow (gimple_stmt_iterator *gsi, location_t loc,
1034 tree arg0, tree arg1)
1036 REAL_VALUE_TYPE c, cint;
1039 /* If the exponent isn't a constant, there's nothing of interest
1041 if (TREE_CODE (arg1) != REAL_CST)
1044 /* If the exponent is equivalent to an integer, expand it into
1045 multiplies when profitable. */
1046 c = TREE_REAL_CST (arg1);
1047 n = real_to_integer (&c);
1048 real_from_integer (&cint, VOIDmode, n, n < 0 ? -1 : 0, 0);
1050 if (real_identical (&c, &cint)
1051 && ((n >= -1 && n <= 2)
1052 || (flag_unsafe_math_optimizations
1053 && optimize_insn_for_speed_p ()
1054 && powi_cost (n) <= POWI_MAX_MULTS)))
1055 return gimple_expand_builtin_powi (gsi, loc, arg0, n);
1060 /* Go through all calls to sin, cos and cexpi and call execute_cse_sincos_1
1061 on the SSA_NAME argument of each of them. Also expand powi(x,n) into
1062 an optimal number of multiplies, when n is a constant. */
1065 execute_cse_sincos (void)
1068 bool cfg_changed = false;
1070 calculate_dominance_info (CDI_DOMINATORS);
1071 memset (&sincos_stats, 0, sizeof (sincos_stats));
1075 gimple_stmt_iterator gsi;
1077 for (gsi = gsi_after_labels (bb); !gsi_end_p (gsi); gsi_next (&gsi))
1079 gimple stmt = gsi_stmt (gsi);
1082 if (is_gimple_call (stmt)
1083 && gimple_call_lhs (stmt)
1084 && (fndecl = gimple_call_fndecl (stmt))
1085 && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
1087 tree arg, arg0, arg1, result;
1091 switch (DECL_FUNCTION_CODE (fndecl))
1093 CASE_FLT_FN (BUILT_IN_COS):
1094 CASE_FLT_FN (BUILT_IN_SIN):
1095 CASE_FLT_FN (BUILT_IN_CEXPI):
1096 /* Make sure we have either sincos or cexp. */
1097 if (!TARGET_HAS_SINCOS && !TARGET_C99_FUNCTIONS)
1100 arg = gimple_call_arg (stmt, 0);
1101 if (TREE_CODE (arg) == SSA_NAME)
1102 cfg_changed |= execute_cse_sincos_1 (arg);
1105 CASE_FLT_FN (BUILT_IN_POW):
1106 arg0 = gimple_call_arg (stmt, 0);
1107 arg1 = gimple_call_arg (stmt, 1);
1109 loc = gimple_location (stmt);
1110 result = gimple_expand_builtin_pow (&gsi, loc, arg0, arg1);
1114 tree lhs = gimple_get_lhs (stmt);
1115 gimple new_stmt = gimple_build_assign (lhs, result);
1116 gimple_set_location (new_stmt, loc);
1117 unlink_stmt_vdef (stmt);
1118 gsi_replace (&gsi, new_stmt, true);
1122 CASE_FLT_FN (BUILT_IN_POWI):
1123 arg0 = gimple_call_arg (stmt, 0);
1124 arg1 = gimple_call_arg (stmt, 1);
1125 if (!host_integerp (arg1, 0))
1128 n = TREE_INT_CST_LOW (arg1);
1129 loc = gimple_location (stmt);
1130 result = gimple_expand_builtin_powi (&gsi, loc, arg0, n);
1134 tree lhs = gimple_get_lhs (stmt);
1135 gimple new_stmt = gimple_build_assign (lhs, result);
1136 gimple_set_location (new_stmt, loc);
1137 unlink_stmt_vdef (stmt);
1138 gsi_replace (&gsi, new_stmt, true);
1148 statistics_counter_event (cfun, "sincos statements inserted",
1149 sincos_stats.inserted);
1151 free_dominance_info (CDI_DOMINATORS);
1152 return cfg_changed ? TODO_cleanup_cfg : 0;
1156 gate_cse_sincos (void)
1158 /* We no longer require either sincos or cexp, since powi expansion
1159 piggybacks on this pass. */
1163 struct gimple_opt_pass pass_cse_sincos =
1167 "sincos", /* name */
1168 gate_cse_sincos, /* gate */
1169 execute_cse_sincos, /* execute */
1172 0, /* static_pass_number */
1173 TV_NONE, /* tv_id */
1174 PROP_ssa, /* properties_required */
1175 0, /* properties_provided */
1176 0, /* properties_destroyed */
1177 0, /* todo_flags_start */
1178 TODO_dump_func | TODO_update_ssa | TODO_verify_ssa
1179 | TODO_verify_stmts /* todo_flags_finish */
1183 /* A symbolic number is used to detect byte permutation and selection
1184 patterns. Therefore the field N contains an artificial number
1185 consisting of byte size markers:
1187 0 - byte has the value 0
1188 1..size - byte contains the content of the byte
1189 number indexed with that value minus one */
1191 struct symbolic_number {
1192 unsigned HOST_WIDEST_INT n;
1196 /* Perform a SHIFT or ROTATE operation by COUNT bits on symbolic
1197 number N. Return false if the requested operation is not permitted
1198 on a symbolic number. */
1201 do_shift_rotate (enum tree_code code,
1202 struct symbolic_number *n,
1208 /* Zero out the extra bits of N in order to avoid them being shifted
1209 into the significant bits. */
1210 if (n->size < (int)sizeof (HOST_WIDEST_INT))
1211 n->n &= ((unsigned HOST_WIDEST_INT)1 << (n->size * BITS_PER_UNIT)) - 1;
1222 n->n = (n->n << count) | (n->n >> ((n->size * BITS_PER_UNIT) - count));
1225 n->n = (n->n >> count) | (n->n << ((n->size * BITS_PER_UNIT) - count));
1233 /* Perform sanity checking for the symbolic number N and the gimple
1237 verify_symbolic_number_p (struct symbolic_number *n, gimple stmt)
1241 lhs_type = gimple_expr_type (stmt);
1243 if (TREE_CODE (lhs_type) != INTEGER_TYPE)
1246 if (TYPE_PRECISION (lhs_type) != n->size * BITS_PER_UNIT)
1252 /* find_bswap_1 invokes itself recursively with N and tries to perform
1253 the operation given by the rhs of STMT on the result. If the
1254 operation could successfully be executed the function returns the
1255 tree expression of the source operand and NULL otherwise. */
1258 find_bswap_1 (gimple stmt, struct symbolic_number *n, int limit)
1260 enum tree_code code;
1261 tree rhs1, rhs2 = NULL;
1262 gimple rhs1_stmt, rhs2_stmt;
1264 enum gimple_rhs_class rhs_class;
1266 if (!limit || !is_gimple_assign (stmt))
1269 rhs1 = gimple_assign_rhs1 (stmt);
1271 if (TREE_CODE (rhs1) != SSA_NAME)
1274 code = gimple_assign_rhs_code (stmt);
1275 rhs_class = gimple_assign_rhs_class (stmt);
1276 rhs1_stmt = SSA_NAME_DEF_STMT (rhs1);
1278 if (rhs_class == GIMPLE_BINARY_RHS)
1279 rhs2 = gimple_assign_rhs2 (stmt);
1281 /* Handle unary rhs and binary rhs with integer constants as second
1284 if (rhs_class == GIMPLE_UNARY_RHS
1285 || (rhs_class == GIMPLE_BINARY_RHS
1286 && TREE_CODE (rhs2) == INTEGER_CST))
1288 if (code != BIT_AND_EXPR
1289 && code != LSHIFT_EXPR
1290 && code != RSHIFT_EXPR
1291 && code != LROTATE_EXPR
1292 && code != RROTATE_EXPR
1294 && code != CONVERT_EXPR)
1297 source_expr1 = find_bswap_1 (rhs1_stmt, n, limit - 1);
1299 /* If find_bswap_1 returned NULL STMT is a leaf node and we have
1300 to initialize the symbolic number. */
1303 /* Set up the symbolic number N by setting each byte to a
1304 value between 1 and the byte size of rhs1. The highest
1305 order byte is set to n->size and the lowest order
1307 n->size = TYPE_PRECISION (TREE_TYPE (rhs1));
1308 if (n->size % BITS_PER_UNIT != 0)
1310 n->size /= BITS_PER_UNIT;
1311 n->n = (sizeof (HOST_WIDEST_INT) < 8 ? 0 :
1312 (unsigned HOST_WIDEST_INT)0x08070605 << 32 | 0x04030201);
1314 if (n->size < (int)sizeof (HOST_WIDEST_INT))
1315 n->n &= ((unsigned HOST_WIDEST_INT)1 <<
1316 (n->size * BITS_PER_UNIT)) - 1;
1318 source_expr1 = rhs1;
1326 unsigned HOST_WIDEST_INT val = widest_int_cst_value (rhs2);
1327 unsigned HOST_WIDEST_INT tmp = val;
1329 /* Only constants masking full bytes are allowed. */
1330 for (i = 0; i < n->size; i++, tmp >>= BITS_PER_UNIT)
1331 if ((tmp & 0xff) != 0 && (tmp & 0xff) != 0xff)
1341 if (!do_shift_rotate (code, n, (int)TREE_INT_CST_LOW (rhs2)))
1348 type_size = TYPE_PRECISION (gimple_expr_type (stmt));
1349 if (type_size % BITS_PER_UNIT != 0)
1352 if (type_size / BITS_PER_UNIT < (int)(sizeof (HOST_WIDEST_INT)))
1354 /* If STMT casts to a smaller type mask out the bits not
1355 belonging to the target type. */
1356 n->n &= ((unsigned HOST_WIDEST_INT)1 << type_size) - 1;
1358 n->size = type_size / BITS_PER_UNIT;
1364 return verify_symbolic_number_p (n, stmt) ? source_expr1 : NULL;
1367 /* Handle binary rhs. */
1369 if (rhs_class == GIMPLE_BINARY_RHS)
1371 struct symbolic_number n1, n2;
1374 if (code != BIT_IOR_EXPR)
1377 if (TREE_CODE (rhs2) != SSA_NAME)
1380 rhs2_stmt = SSA_NAME_DEF_STMT (rhs2);
1385 source_expr1 = find_bswap_1 (rhs1_stmt, &n1, limit - 1);
1390 source_expr2 = find_bswap_1 (rhs2_stmt, &n2, limit - 1);
1392 if (source_expr1 != source_expr2
1393 || n1.size != n2.size)
1399 if (!verify_symbolic_number_p (n, stmt))
1406 return source_expr1;
1411 /* Check if STMT completes a bswap implementation consisting of ORs,
1412 SHIFTs and ANDs. Return the source tree expression on which the
1413 byte swap is performed and NULL if no bswap was found. */
1416 find_bswap (gimple stmt)
1418 /* The number which the find_bswap result should match in order to
1419 have a full byte swap. The number is shifted to the left according
1420 to the size of the symbolic number before using it. */
1421 unsigned HOST_WIDEST_INT cmp =
1422 sizeof (HOST_WIDEST_INT) < 8 ? 0 :
1423 (unsigned HOST_WIDEST_INT)0x01020304 << 32 | 0x05060708;
1425 struct symbolic_number n;
1428 /* The last parameter determines the depth search limit. It usually
1429 correlates directly to the number of bytes to be touched. We
1430 increase that number by one here in order to also cover signed ->
1431 unsigned conversions of the src operand as can be seen in
1433 source_expr = find_bswap_1 (stmt, &n,
1435 TYPE_SIZE_UNIT (gimple_expr_type (stmt))) + 1);
1440 /* Zero out the extra bits of N and CMP. */
1441 if (n.size < (int)sizeof (HOST_WIDEST_INT))
1443 unsigned HOST_WIDEST_INT mask =
1444 ((unsigned HOST_WIDEST_INT)1 << (n.size * BITS_PER_UNIT)) - 1;
1447 cmp >>= (sizeof (HOST_WIDEST_INT) - n.size) * BITS_PER_UNIT;
1450 /* A complete byte swap should make the symbolic number to start
1451 with the largest digit in the highest order byte. */
1458 /* Find manual byte swap implementations and turn them into a bswap
1459 builtin invokation. */
1462 execute_optimize_bswap (void)
1465 bool bswap32_p, bswap64_p;
1466 bool changed = false;
1467 tree bswap32_type = NULL_TREE, bswap64_type = NULL_TREE;
1469 if (BITS_PER_UNIT != 8)
1472 if (sizeof (HOST_WIDEST_INT) < 8)
1475 bswap32_p = (built_in_decls[BUILT_IN_BSWAP32]
1476 && optab_handler (bswap_optab, SImode) != CODE_FOR_nothing);
1477 bswap64_p = (built_in_decls[BUILT_IN_BSWAP64]
1478 && (optab_handler (bswap_optab, DImode) != CODE_FOR_nothing
1479 || (bswap32_p && word_mode == SImode)));
1481 if (!bswap32_p && !bswap64_p)
1484 /* Determine the argument type of the builtins. The code later on
1485 assumes that the return and argument type are the same. */
1488 tree fndecl = built_in_decls[BUILT_IN_BSWAP32];
1489 bswap32_type = TREE_VALUE (TYPE_ARG_TYPES (TREE_TYPE (fndecl)));
1494 tree fndecl = built_in_decls[BUILT_IN_BSWAP64];
1495 bswap64_type = TREE_VALUE (TYPE_ARG_TYPES (TREE_TYPE (fndecl)));
1498 memset (&bswap_stats, 0, sizeof (bswap_stats));
1502 gimple_stmt_iterator gsi;
1504 for (gsi = gsi_after_labels (bb); !gsi_end_p (gsi); gsi_next (&gsi))
1506 gimple stmt = gsi_stmt (gsi);
1507 tree bswap_src, bswap_type;
1509 tree fndecl = NULL_TREE;
1513 if (!is_gimple_assign (stmt)
1514 || gimple_assign_rhs_code (stmt) != BIT_IOR_EXPR)
1517 type_size = TYPE_PRECISION (gimple_expr_type (stmt));
1524 fndecl = built_in_decls[BUILT_IN_BSWAP32];
1525 bswap_type = bswap32_type;
1531 fndecl = built_in_decls[BUILT_IN_BSWAP64];
1532 bswap_type = bswap64_type;
1542 bswap_src = find_bswap (stmt);
1548 if (type_size == 32)
1549 bswap_stats.found_32bit++;
1551 bswap_stats.found_64bit++;
1553 bswap_tmp = bswap_src;
1555 /* Convert the src expression if necessary. */
1556 if (!useless_type_conversion_p (TREE_TYPE (bswap_tmp), bswap_type))
1558 gimple convert_stmt;
1560 bswap_tmp = create_tmp_var (bswap_type, "bswapsrc");
1561 add_referenced_var (bswap_tmp);
1562 bswap_tmp = make_ssa_name (bswap_tmp, NULL);
1564 convert_stmt = gimple_build_assign_with_ops (
1565 CONVERT_EXPR, bswap_tmp, bswap_src, NULL);
1566 gsi_insert_before (&gsi, convert_stmt, GSI_SAME_STMT);
1569 call = gimple_build_call (fndecl, 1, bswap_tmp);
1571 bswap_tmp = gimple_assign_lhs (stmt);
1573 /* Convert the result if necessary. */
1574 if (!useless_type_conversion_p (TREE_TYPE (bswap_tmp), bswap_type))
1576 gimple convert_stmt;
1578 bswap_tmp = create_tmp_var (bswap_type, "bswapdst");
1579 add_referenced_var (bswap_tmp);
1580 bswap_tmp = make_ssa_name (bswap_tmp, NULL);
1581 convert_stmt = gimple_build_assign_with_ops (
1582 CONVERT_EXPR, gimple_assign_lhs (stmt), bswap_tmp, NULL);
1583 gsi_insert_after (&gsi, convert_stmt, GSI_SAME_STMT);
1586 gimple_call_set_lhs (call, bswap_tmp);
1590 fprintf (dump_file, "%d bit bswap implementation found at: ",
1592 print_gimple_stmt (dump_file, stmt, 0, 0);
1595 gsi_insert_after (&gsi, call, GSI_SAME_STMT);
1596 gsi_remove (&gsi, true);
1600 statistics_counter_event (cfun, "32-bit bswap implementations found",
1601 bswap_stats.found_32bit);
1602 statistics_counter_event (cfun, "64-bit bswap implementations found",
1603 bswap_stats.found_64bit);
1605 return (changed ? TODO_dump_func | TODO_update_ssa | TODO_verify_ssa
1606 | TODO_verify_stmts : 0);
1610 gate_optimize_bswap (void)
1612 return flag_expensive_optimizations && optimize;
1615 struct gimple_opt_pass pass_optimize_bswap =
1620 gate_optimize_bswap, /* gate */
1621 execute_optimize_bswap, /* execute */
1624 0, /* static_pass_number */
1625 TV_NONE, /* tv_id */
1626 PROP_ssa, /* properties_required */
1627 0, /* properties_provided */
1628 0, /* properties_destroyed */
1629 0, /* todo_flags_start */
1630 0 /* todo_flags_finish */
1634 /* Return true if RHS is a suitable operand for a widening multiplication.
1635 There are two cases:
1637 - RHS makes some value twice as wide. Store that value in *NEW_RHS_OUT
1638 if so, and store its type in *TYPE_OUT.
1640 - RHS is an integer constant. Store that value in *NEW_RHS_OUT if so,
1641 but leave *TYPE_OUT untouched. */
1644 is_widening_mult_rhs_p (tree rhs, tree *type_out, tree *new_rhs_out)
1647 tree type, type1, rhs1;
1648 enum tree_code rhs_code;
1650 if (TREE_CODE (rhs) == SSA_NAME)
1652 type = TREE_TYPE (rhs);
1653 stmt = SSA_NAME_DEF_STMT (rhs);
1654 if (!is_gimple_assign (stmt))
1657 rhs_code = gimple_assign_rhs_code (stmt);
1658 if (TREE_CODE (type) == INTEGER_TYPE
1659 ? !CONVERT_EXPR_CODE_P (rhs_code)
1660 : rhs_code != FIXED_CONVERT_EXPR)
1663 rhs1 = gimple_assign_rhs1 (stmt);
1664 type1 = TREE_TYPE (rhs1);
1665 if (TREE_CODE (type1) != TREE_CODE (type)
1666 || TYPE_PRECISION (type1) * 2 != TYPE_PRECISION (type))
1669 *new_rhs_out = rhs1;
1674 if (TREE_CODE (rhs) == INTEGER_CST)
1684 /* Return true if STMT performs a widening multiplication. If so,
1685 store the unwidened types of the operands in *TYPE1_OUT and *TYPE2_OUT
1686 respectively. Also fill *RHS1_OUT and *RHS2_OUT such that converting
1687 those operands to types *TYPE1_OUT and *TYPE2_OUT would give the
1688 operands of the multiplication. */
1691 is_widening_mult_p (gimple stmt,
1692 tree *type1_out, tree *rhs1_out,
1693 tree *type2_out, tree *rhs2_out)
1697 type = TREE_TYPE (gimple_assign_lhs (stmt));
1698 if (TREE_CODE (type) != INTEGER_TYPE
1699 && TREE_CODE (type) != FIXED_POINT_TYPE)
1702 if (!is_widening_mult_rhs_p (gimple_assign_rhs1 (stmt), type1_out, rhs1_out))
1705 if (!is_widening_mult_rhs_p (gimple_assign_rhs2 (stmt), type2_out, rhs2_out))
1708 if (*type1_out == NULL)
1710 if (*type2_out == NULL || !int_fits_type_p (*rhs1_out, *type2_out))
1712 *type1_out = *type2_out;
1715 if (*type2_out == NULL)
1717 if (!int_fits_type_p (*rhs2_out, *type1_out))
1719 *type2_out = *type1_out;
1725 /* Process a single gimple statement STMT, which has a MULT_EXPR as
1726 its rhs, and try to convert it into a WIDEN_MULT_EXPR. The return
1727 value is true iff we converted the statement. */
1730 convert_mult_to_widen (gimple stmt)
1732 tree lhs, rhs1, rhs2, type, type1, type2;
1733 enum insn_code handler;
1735 lhs = gimple_assign_lhs (stmt);
1736 type = TREE_TYPE (lhs);
1737 if (TREE_CODE (type) != INTEGER_TYPE)
1740 if (!is_widening_mult_p (stmt, &type1, &rhs1, &type2, &rhs2))
1743 if (TYPE_UNSIGNED (type1) && TYPE_UNSIGNED (type2))
1744 handler = optab_handler (umul_widen_optab, TYPE_MODE (type));
1745 else if (!TYPE_UNSIGNED (type1) && !TYPE_UNSIGNED (type2))
1746 handler = optab_handler (smul_widen_optab, TYPE_MODE (type));
1748 handler = optab_handler (usmul_widen_optab, TYPE_MODE (type));
1750 if (handler == CODE_FOR_nothing)
1753 gimple_assign_set_rhs1 (stmt, fold_convert (type1, rhs1));
1754 gimple_assign_set_rhs2 (stmt, fold_convert (type2, rhs2));
1755 gimple_assign_set_rhs_code (stmt, WIDEN_MULT_EXPR);
1757 widen_mul_stats.widen_mults_inserted++;
1761 /* Process a single gimple statement STMT, which is found at the
1762 iterator GSI and has a either a PLUS_EXPR or a MINUS_EXPR as its
1763 rhs (given by CODE), and try to convert it into a
1764 WIDEN_MULT_PLUS_EXPR or a WIDEN_MULT_MINUS_EXPR. The return value
1765 is true iff we converted the statement. */
1768 convert_plusminus_to_widen (gimple_stmt_iterator *gsi, gimple stmt,
1769 enum tree_code code)
1771 gimple rhs1_stmt = NULL, rhs2_stmt = NULL;
1772 tree type, type1, type2;
1773 tree lhs, rhs1, rhs2, mult_rhs1, mult_rhs2, add_rhs;
1774 enum tree_code rhs1_code = ERROR_MARK, rhs2_code = ERROR_MARK;
1776 enum tree_code wmult_code;
1778 lhs = gimple_assign_lhs (stmt);
1779 type = TREE_TYPE (lhs);
1780 if (TREE_CODE (type) != INTEGER_TYPE
1781 && TREE_CODE (type) != FIXED_POINT_TYPE)
1784 if (code == MINUS_EXPR)
1785 wmult_code = WIDEN_MULT_MINUS_EXPR;
1787 wmult_code = WIDEN_MULT_PLUS_EXPR;
1789 rhs1 = gimple_assign_rhs1 (stmt);
1790 rhs2 = gimple_assign_rhs2 (stmt);
1792 if (TREE_CODE (rhs1) == SSA_NAME)
1794 rhs1_stmt = SSA_NAME_DEF_STMT (rhs1);
1795 if (is_gimple_assign (rhs1_stmt))
1796 rhs1_code = gimple_assign_rhs_code (rhs1_stmt);
1801 if (TREE_CODE (rhs2) == SSA_NAME)
1803 rhs2_stmt = SSA_NAME_DEF_STMT (rhs2);
1804 if (is_gimple_assign (rhs2_stmt))
1805 rhs2_code = gimple_assign_rhs_code (rhs2_stmt);
1810 if (code == PLUS_EXPR && rhs1_code == MULT_EXPR)
1812 if (!is_widening_mult_p (rhs1_stmt, &type1, &mult_rhs1,
1813 &type2, &mult_rhs2))
1817 else if (rhs2_code == MULT_EXPR)
1819 if (!is_widening_mult_p (rhs2_stmt, &type1, &mult_rhs1,
1820 &type2, &mult_rhs2))
1824 else if (code == PLUS_EXPR && rhs1_code == WIDEN_MULT_EXPR)
1826 mult_rhs1 = gimple_assign_rhs1 (rhs1_stmt);
1827 mult_rhs2 = gimple_assign_rhs2 (rhs1_stmt);
1828 type1 = TREE_TYPE (mult_rhs1);
1829 type2 = TREE_TYPE (mult_rhs2);
1832 else if (rhs2_code == WIDEN_MULT_EXPR)
1834 mult_rhs1 = gimple_assign_rhs1 (rhs2_stmt);
1835 mult_rhs2 = gimple_assign_rhs2 (rhs2_stmt);
1836 type1 = TREE_TYPE (mult_rhs1);
1837 type2 = TREE_TYPE (mult_rhs2);
1843 if (TYPE_UNSIGNED (type1) != TYPE_UNSIGNED (type2))
1846 /* Verify that the machine can perform a widening multiply
1847 accumulate in this mode/signedness combination, otherwise
1848 this transformation is likely to pessimize code. */
1849 this_optab = optab_for_tree_code (wmult_code, type1, optab_default);
1850 if (optab_handler (this_optab, TYPE_MODE (type)) == CODE_FOR_nothing)
1853 /* ??? May need some type verification here? */
1855 gimple_assign_set_rhs_with_ops_1 (gsi, wmult_code,
1856 fold_convert (type1, mult_rhs1),
1857 fold_convert (type2, mult_rhs2),
1859 update_stmt (gsi_stmt (*gsi));
1860 widen_mul_stats.maccs_inserted++;
1864 /* Combine the multiplication at MUL_STMT with operands MULOP1 and MULOP2
1865 with uses in additions and subtractions to form fused multiply-add
1866 operations. Returns true if successful and MUL_STMT should be removed. */
1869 convert_mult_to_fma (gimple mul_stmt, tree op1, tree op2)
1871 tree mul_result = gimple_get_lhs (mul_stmt);
1872 tree type = TREE_TYPE (mul_result);
1873 gimple use_stmt, neguse_stmt, fma_stmt;
1874 use_operand_p use_p;
1875 imm_use_iterator imm_iter;
1877 if (FLOAT_TYPE_P (type)
1878 && flag_fp_contract_mode == FP_CONTRACT_OFF)
1881 /* We don't want to do bitfield reduction ops. */
1882 if (INTEGRAL_TYPE_P (type)
1883 && (TYPE_PRECISION (type)
1884 != GET_MODE_PRECISION (TYPE_MODE (type))))
1887 /* If the target doesn't support it, don't generate it. We assume that
1888 if fma isn't available then fms, fnma or fnms are not either. */
1889 if (optab_handler (fma_optab, TYPE_MODE (type)) == CODE_FOR_nothing)
1892 /* Make sure that the multiplication statement becomes dead after
1893 the transformation, thus that all uses are transformed to FMAs.
1894 This means we assume that an FMA operation has the same cost
1896 FOR_EACH_IMM_USE_FAST (use_p, imm_iter, mul_result)
1898 enum tree_code use_code;
1899 tree result = mul_result;
1900 bool negate_p = false;
1902 use_stmt = USE_STMT (use_p);
1904 if (is_gimple_debug (use_stmt))
1907 /* For now restrict this operations to single basic blocks. In theory
1908 we would want to support sinking the multiplication in
1914 to form a fma in the then block and sink the multiplication to the
1916 if (gimple_bb (use_stmt) != gimple_bb (mul_stmt))
1919 if (!is_gimple_assign (use_stmt))
1922 use_code = gimple_assign_rhs_code (use_stmt);
1924 /* A negate on the multiplication leads to FNMA. */
1925 if (use_code == NEGATE_EXPR)
1930 result = gimple_assign_lhs (use_stmt);
1932 /* Make sure the negate statement becomes dead with this
1933 single transformation. */
1934 if (!single_imm_use (gimple_assign_lhs (use_stmt),
1935 &use_p, &neguse_stmt))
1938 /* Make sure the multiplication isn't also used on that stmt. */
1939 FOR_EACH_SSA_TREE_OPERAND (use, neguse_stmt, iter, SSA_OP_USE)
1940 if (use == mul_result)
1944 use_stmt = neguse_stmt;
1945 if (gimple_bb (use_stmt) != gimple_bb (mul_stmt))
1947 if (!is_gimple_assign (use_stmt))
1950 use_code = gimple_assign_rhs_code (use_stmt);
1957 if (gimple_assign_rhs2 (use_stmt) == result)
1958 negate_p = !negate_p;
1963 /* FMA can only be formed from PLUS and MINUS. */
1967 /* We can't handle a * b + a * b. */
1968 if (gimple_assign_rhs1 (use_stmt) == gimple_assign_rhs2 (use_stmt))
1971 /* While it is possible to validate whether or not the exact form
1972 that we've recognized is available in the backend, the assumption
1973 is that the transformation is never a loss. For instance, suppose
1974 the target only has the plain FMA pattern available. Consider
1975 a*b-c -> fma(a,b,-c): we've exchanged MUL+SUB for FMA+NEG, which
1976 is still two operations. Consider -(a*b)-c -> fma(-a,b,-c): we
1977 still have 3 operations, but in the FMA form the two NEGs are
1978 independant and could be run in parallel. */
1981 FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, mul_result)
1983 gimple_stmt_iterator gsi = gsi_for_stmt (use_stmt);
1984 enum tree_code use_code;
1985 tree addop, mulop1 = op1, result = mul_result;
1986 bool negate_p = false;
1988 if (is_gimple_debug (use_stmt))
1991 use_code = gimple_assign_rhs_code (use_stmt);
1992 if (use_code == NEGATE_EXPR)
1994 result = gimple_assign_lhs (use_stmt);
1995 single_imm_use (gimple_assign_lhs (use_stmt), &use_p, &neguse_stmt);
1996 gsi_remove (&gsi, true);
1997 release_defs (use_stmt);
1999 use_stmt = neguse_stmt;
2000 gsi = gsi_for_stmt (use_stmt);
2001 use_code = gimple_assign_rhs_code (use_stmt);
2005 if (gimple_assign_rhs1 (use_stmt) == result)
2007 addop = gimple_assign_rhs2 (use_stmt);
2008 /* a * b - c -> a * b + (-c) */
2009 if (gimple_assign_rhs_code (use_stmt) == MINUS_EXPR)
2010 addop = force_gimple_operand_gsi (&gsi,
2011 build1 (NEGATE_EXPR,
2013 true, NULL_TREE, true,
2018 addop = gimple_assign_rhs1 (use_stmt);
2019 /* a - b * c -> (-b) * c + a */
2020 if (gimple_assign_rhs_code (use_stmt) == MINUS_EXPR)
2021 negate_p = !negate_p;
2025 mulop1 = force_gimple_operand_gsi (&gsi,
2026 build1 (NEGATE_EXPR,
2028 true, NULL_TREE, true,
2031 fma_stmt = gimple_build_assign_with_ops3 (FMA_EXPR,
2032 gimple_assign_lhs (use_stmt),
2035 gsi_replace (&gsi, fma_stmt, true);
2036 widen_mul_stats.fmas_inserted++;
2042 /* Find integer multiplications where the operands are extended from
2043 smaller types, and replace the MULT_EXPR with a WIDEN_MULT_EXPR
2044 where appropriate. */
2047 execute_optimize_widening_mul (void)
2050 bool cfg_changed = false;
2052 memset (&widen_mul_stats, 0, sizeof (widen_mul_stats));
2056 gimple_stmt_iterator gsi;
2058 for (gsi = gsi_after_labels (bb); !gsi_end_p (gsi);)
2060 gimple stmt = gsi_stmt (gsi);
2061 enum tree_code code;
2063 if (is_gimple_assign (stmt))
2065 code = gimple_assign_rhs_code (stmt);
2069 if (!convert_mult_to_widen (stmt)
2070 && convert_mult_to_fma (stmt,
2071 gimple_assign_rhs1 (stmt),
2072 gimple_assign_rhs2 (stmt)))
2074 gsi_remove (&gsi, true);
2075 release_defs (stmt);
2082 convert_plusminus_to_widen (&gsi, stmt, code);
2088 else if (is_gimple_call (stmt)
2089 && gimple_call_lhs (stmt))
2091 tree fndecl = gimple_call_fndecl (stmt);
2093 && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
2095 switch (DECL_FUNCTION_CODE (fndecl))
2100 if (TREE_CODE (gimple_call_arg (stmt, 1)) == REAL_CST
2101 && REAL_VALUES_EQUAL
2102 (TREE_REAL_CST (gimple_call_arg (stmt, 1)),
2104 && convert_mult_to_fma (stmt,
2105 gimple_call_arg (stmt, 0),
2106 gimple_call_arg (stmt, 0)))
2108 unlink_stmt_vdef (stmt);
2109 gsi_remove (&gsi, true);
2110 release_defs (stmt);
2111 if (gimple_purge_dead_eh_edges (bb))
2125 statistics_counter_event (cfun, "widening multiplications inserted",
2126 widen_mul_stats.widen_mults_inserted);
2127 statistics_counter_event (cfun, "widening maccs inserted",
2128 widen_mul_stats.maccs_inserted);
2129 statistics_counter_event (cfun, "fused multiply-adds inserted",
2130 widen_mul_stats.fmas_inserted);
2132 return cfg_changed ? TODO_cleanup_cfg : 0;
2136 gate_optimize_widening_mul (void)
2138 return flag_expensive_optimizations && optimize;
2141 struct gimple_opt_pass pass_optimize_widening_mul =
2145 "widening_mul", /* name */
2146 gate_optimize_widening_mul, /* gate */
2147 execute_optimize_widening_mul, /* execute */
2150 0, /* static_pass_number */
2151 TV_NONE, /* tv_id */
2152 PROP_ssa, /* properties_required */
2153 0, /* properties_provided */
2154 0, /* properties_destroyed */
2155 0, /* todo_flags_start */
2159 | TODO_update_ssa /* todo_flags_finish */