1 /* Forward propagation of expressions for single use variables.
2 Copyright (C) 2004, 2005, 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
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
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/>. */
23 #include "coretypes.h"
27 #include "basic-block.h"
29 #include "tree-pretty-print.h"
30 #include "tree-flow.h"
31 #include "tree-pass.h"
32 #include "tree-dump.h"
33 #include "langhooks.h"
38 /* This pass propagates the RHS of assignment statements into use
39 sites of the LHS of the assignment. It's basically a specialized
40 form of tree combination. It is hoped all of this can disappear
41 when we have a generalized tree combiner.
43 One class of common cases we handle is forward propagating a single use
44 variable into a COND_EXPR.
48 if (x) goto ... else goto ...
50 Will be transformed into:
53 if (a COND b) goto ... else goto ...
55 Similarly for the tests (x == 0), (x != 0), (x == 1) and (x != 1).
57 Or (assuming c1 and c2 are constants):
61 if (x EQ/NEQ c2) goto ... else goto ...
63 Will be transformed into:
66 if (a EQ/NEQ (c2 - c1)) goto ... else goto ...
68 Similarly for x = a - c1.
74 if (x) goto ... else goto ...
76 Will be transformed into:
79 if (a == 0) goto ... else goto ...
81 Similarly for the tests (x == 0), (x != 0), (x == 1) and (x != 1).
82 For these cases, we propagate A into all, possibly more than one,
83 COND_EXPRs that use X.
89 if (x) goto ... else goto ...
91 Will be transformed into:
94 if (a != 0) goto ... else goto ...
96 (Assuming a is an integral type and x is a boolean or x is an
97 integral and a is a boolean.)
99 Similarly for the tests (x == 0), (x != 0), (x == 1) and (x != 1).
100 For these cases, we propagate A into all, possibly more than one,
101 COND_EXPRs that use X.
103 In addition to eliminating the variable and the statement which assigns
104 a value to the variable, we may be able to later thread the jump without
105 adding insane complexity in the dominator optimizer.
107 Also note these transformations can cascade. We handle this by having
108 a worklist of COND_EXPR statements to examine. As we make a change to
109 a statement, we put it back on the worklist to examine on the next
110 iteration of the main loop.
112 A second class of propagation opportunities arises for ADDR_EXPR
123 ptr = (type1*)&type2var;
126 Will get turned into (if type1 and type2 are the same size
127 and neither have volatile on them):
128 res = VIEW_CONVERT_EXPR<type1>(type2var)
133 ptr2 = ptr + <constant>;
137 ptr2 = &x[constant/elementsize];
142 offset = index * element_size;
143 offset_p = (pointer) offset;
144 ptr2 = ptr + offset_p
146 Will get turned into:
154 Provided that decl has known alignment >= 2, will get turned into
158 We also propagate casts into SWITCH_EXPR and COND_EXPR conditions to
159 allow us to remove the cast and {NOT_EXPR,NEG_EXPR} into a subsequent
162 This will (of course) be extended as other needs arise. */
164 static bool forward_propagate_addr_expr (tree name, tree rhs);
166 /* Set to true if we delete EH edges during the optimization. */
167 static bool cfg_changed;
169 static tree rhs_to_tree (tree type, gimple stmt);
171 /* Get the next statement we can propagate NAME's value into skipping
172 trivial copies. Returns the statement that is suitable as a
173 propagation destination or NULL_TREE if there is no such one.
174 This only returns destinations in a single-use chain. FINAL_NAME_P
175 if non-NULL is written to the ssa name that represents the use. */
178 get_prop_dest_stmt (tree name, tree *final_name_p)
184 /* If name has multiple uses, bail out. */
185 if (!single_imm_use (name, &use, &use_stmt))
188 /* If this is not a trivial copy, we found it. */
189 if (!gimple_assign_ssa_name_copy_p (use_stmt)
190 || gimple_assign_rhs1 (use_stmt) != name)
193 /* Continue searching uses of the copy destination. */
194 name = gimple_assign_lhs (use_stmt);
198 *final_name_p = name;
203 /* Get the statement we can propagate from into NAME skipping
204 trivial copies. Returns the statement which defines the
205 propagation source or NULL_TREE if there is no such one.
206 If SINGLE_USE_ONLY is set considers only sources which have
207 a single use chain up to NAME. If SINGLE_USE_P is non-null,
208 it is set to whether the chain to NAME is a single use chain
209 or not. SINGLE_USE_P is not written to if SINGLE_USE_ONLY is set. */
212 get_prop_source_stmt (tree name, bool single_use_only, bool *single_use_p)
214 bool single_use = true;
217 gimple def_stmt = SSA_NAME_DEF_STMT (name);
219 if (!has_single_use (name))
226 /* If name is defined by a PHI node or is the default def, bail out. */
227 if (!is_gimple_assign (def_stmt))
230 /* If def_stmt is not a simple copy, we possibly found it. */
231 if (!gimple_assign_ssa_name_copy_p (def_stmt))
235 if (!single_use_only && single_use_p)
236 *single_use_p = single_use;
238 /* We can look through pointer conversions in the search
239 for a useful stmt for the comparison folding. */
240 rhs = gimple_assign_rhs1 (def_stmt);
241 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
242 && TREE_CODE (rhs) == SSA_NAME
243 && POINTER_TYPE_P (TREE_TYPE (gimple_assign_lhs (def_stmt)))
244 && POINTER_TYPE_P (TREE_TYPE (rhs)))
251 /* Continue searching the def of the copy source name. */
252 name = gimple_assign_rhs1 (def_stmt);
257 /* Checks if the destination ssa name in DEF_STMT can be used as
258 propagation source. Returns true if so, otherwise false. */
261 can_propagate_from (gimple def_stmt)
263 gcc_assert (is_gimple_assign (def_stmt));
265 /* If the rhs has side-effects we cannot propagate from it. */
266 if (gimple_has_volatile_ops (def_stmt))
269 /* If the rhs is a load we cannot propagate from it. */
270 if (TREE_CODE_CLASS (gimple_assign_rhs_code (def_stmt)) == tcc_reference
271 || TREE_CODE_CLASS (gimple_assign_rhs_code (def_stmt)) == tcc_declaration)
274 /* Constants can be always propagated. */
275 if (gimple_assign_single_p (def_stmt)
276 && is_gimple_min_invariant (gimple_assign_rhs1 (def_stmt)))
279 /* We cannot propagate ssa names that occur in abnormal phi nodes. */
280 if (stmt_references_abnormal_ssa_name (def_stmt))
283 /* If the definition is a conversion of a pointer to a function type,
284 then we can not apply optimizations as some targets require
285 function pointers to be canonicalized and in this case this
286 optimization could eliminate a necessary canonicalization. */
287 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)))
289 tree rhs = gimple_assign_rhs1 (def_stmt);
290 if (POINTER_TYPE_P (TREE_TYPE (rhs))
291 && TREE_CODE (TREE_TYPE (TREE_TYPE (rhs))) == FUNCTION_TYPE)
298 /* Remove a copy chain ending in NAME along the defs.
299 If NAME was replaced in its only use then this function can be used
300 to clean up dead stmts. Returns true if cleanup-cfg has to run. */
303 remove_prop_source_from_use (tree name)
305 gimple_stmt_iterator gsi;
307 bool cfg_changed = false;
312 if (!has_zero_uses (name))
315 stmt = SSA_NAME_DEF_STMT (name);
316 gsi = gsi_for_stmt (stmt);
317 bb = gimple_bb (stmt);
319 gsi_remove (&gsi, true);
320 cfg_changed |= gimple_purge_dead_eh_edges (bb);
322 name = (gimple_assign_copy_p (stmt)) ? gimple_assign_rhs1 (stmt) : NULL;
323 } while (name && TREE_CODE (name) == SSA_NAME);
328 /* Return the rhs of a gimple_assign STMT in a form of a single tree,
329 converted to type TYPE.
331 This should disappear, but is needed so we can combine expressions and use
332 the fold() interfaces. Long term, we need to develop folding and combine
333 routines that deal with gimple exclusively . */
336 rhs_to_tree (tree type, gimple stmt)
338 location_t loc = gimple_location (stmt);
339 enum tree_code code = gimple_assign_rhs_code (stmt);
340 if (get_gimple_rhs_class (code) == GIMPLE_TERNARY_RHS)
341 return fold_build3_loc (loc, code, type, gimple_assign_rhs1 (stmt),
342 gimple_assign_rhs2 (stmt),
343 gimple_assign_rhs3 (stmt));
344 else if (get_gimple_rhs_class (code) == GIMPLE_BINARY_RHS)
345 return fold_build2_loc (loc, code, type, gimple_assign_rhs1 (stmt),
346 gimple_assign_rhs2 (stmt));
347 else if (get_gimple_rhs_class (code) == GIMPLE_UNARY_RHS)
348 return build1 (code, type, gimple_assign_rhs1 (stmt));
349 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS)
350 return gimple_assign_rhs1 (stmt);
355 /* Combine OP0 CODE OP1 in the context of a COND_EXPR. Returns
356 the folded result in a form suitable for COND_EXPR_COND or
357 NULL_TREE, if there is no suitable simplified form. If
358 INVARIANT_ONLY is true only gimple_min_invariant results are
359 considered simplified. */
362 combine_cond_expr_cond (location_t loc, enum tree_code code, tree type,
363 tree op0, tree op1, bool invariant_only)
367 gcc_assert (TREE_CODE_CLASS (code) == tcc_comparison);
369 t = fold_binary_loc (loc, code, type, op0, op1);
373 /* Require that we got a boolean type out if we put one in. */
374 gcc_assert (TREE_CODE (TREE_TYPE (t)) == TREE_CODE (type));
376 /* Canonicalize the combined condition for use in a COND_EXPR. */
377 t = canonicalize_cond_expr_cond (t);
379 /* Bail out if we required an invariant but didn't get one. */
380 if (!t || (invariant_only && !is_gimple_min_invariant (t)))
386 /* Propagate from the ssa name definition statements of COND_EXPR
387 in GIMPLE_COND statement STMT into the conditional if that simplifies it.
388 Returns zero if no statement was changed, one if there were
389 changes and two if cfg_cleanup needs to run.
391 This must be kept in sync with forward_propagate_into_cond. */
394 forward_propagate_into_gimple_cond (gimple stmt)
396 int did_something = 0;
397 location_t loc = gimple_location (stmt);
400 tree tmp = NULL_TREE;
401 tree name = NULL_TREE, rhs0 = NULL_TREE, rhs1 = NULL_TREE;
403 bool single_use0_p = false, single_use1_p = false;
404 enum tree_code code = gimple_cond_code (stmt);
406 /* We can do tree combining on SSA_NAME and comparison expressions. */
407 if (TREE_CODE_CLASS (gimple_cond_code (stmt)) == tcc_comparison)
409 /* For comparisons use the first operand, that is likely to
410 simplify comparisons against constants. */
411 if (TREE_CODE (gimple_cond_lhs (stmt)) == SSA_NAME)
413 name = gimple_cond_lhs (stmt);
414 def_stmt = get_prop_source_stmt (name, false, &single_use0_p);
415 if (def_stmt && can_propagate_from (def_stmt))
417 tree op1 = gimple_cond_rhs (stmt);
418 rhs0 = rhs_to_tree (TREE_TYPE (op1), def_stmt);
419 tmp = combine_cond_expr_cond (loc, code, boolean_type_node,
420 rhs0, op1, !single_use0_p);
423 /* If that wasn't successful, try the second operand. */
425 && TREE_CODE (gimple_cond_rhs (stmt)) == SSA_NAME)
427 tree op0 = gimple_cond_lhs (stmt);
428 name = gimple_cond_rhs (stmt);
429 def_stmt = get_prop_source_stmt (name, false, &single_use1_p);
430 if (!def_stmt || !can_propagate_from (def_stmt))
431 return did_something;
433 rhs1 = rhs_to_tree (TREE_TYPE (op0), def_stmt);
434 tmp = combine_cond_expr_cond (loc, code, boolean_type_node, op0,
435 rhs1, !single_use1_p);
437 /* If that wasn't successful either, try both operands. */
440 && rhs1 != NULL_TREE)
441 tmp = combine_cond_expr_cond (loc, code, boolean_type_node, rhs0,
442 fold_convert_loc (loc,
445 !(single_use0_p && single_use1_p));
450 if (dump_file && tmp)
452 tree cond = build2 (gimple_cond_code (stmt),
454 gimple_cond_lhs (stmt),
455 gimple_cond_rhs (stmt));
456 fprintf (dump_file, " Replaced '");
457 print_generic_expr (dump_file, cond, 0);
458 fprintf (dump_file, "' with '");
459 print_generic_expr (dump_file, tmp, 0);
460 fprintf (dump_file, "'\n");
463 gimple_cond_set_condition_from_tree (stmt, unshare_expr (tmp));
466 /* Remove defining statements. */
467 if (remove_prop_source_from_use (name)
468 || is_gimple_min_invariant (tmp))
470 else if (did_something == 0)
473 /* Continue combining. */
480 return did_something;
484 /* Propagate from the ssa name definition statements of COND_EXPR
485 in the rhs of statement STMT into the conditional if that simplifies it.
486 Returns zero if no statement was changed, one if there were
487 changes and two if cfg_cleanup needs to run.
489 This must be kept in sync with forward_propagate_into_gimple_cond. */
492 forward_propagate_into_cond (gimple_stmt_iterator *gsi_p)
494 gimple stmt = gsi_stmt (*gsi_p);
495 location_t loc = gimple_location (stmt);
496 int did_something = 0;
499 tree tmp = NULL_TREE;
500 tree cond = gimple_assign_rhs1 (stmt);
501 tree name, rhs0 = NULL_TREE, rhs1 = NULL_TREE;
503 bool single_use0_p = false, single_use1_p = false;
505 /* We can do tree combining on SSA_NAME and comparison expressions. */
506 if (COMPARISON_CLASS_P (cond)
507 && TREE_CODE (TREE_OPERAND (cond, 0)) == SSA_NAME)
509 /* For comparisons use the first operand, that is likely to
510 simplify comparisons against constants. */
511 name = TREE_OPERAND (cond, 0);
512 def_stmt = get_prop_source_stmt (name, false, &single_use0_p);
513 if (def_stmt && can_propagate_from (def_stmt))
515 tree op1 = TREE_OPERAND (cond, 1);
516 rhs0 = rhs_to_tree (TREE_TYPE (op1), def_stmt);
517 tmp = combine_cond_expr_cond (loc, TREE_CODE (cond),
519 rhs0, op1, !single_use0_p);
521 /* If that wasn't successful, try the second operand. */
523 && TREE_CODE (TREE_OPERAND (cond, 1)) == SSA_NAME)
525 tree op0 = TREE_OPERAND (cond, 0);
526 name = TREE_OPERAND (cond, 1);
527 def_stmt = get_prop_source_stmt (name, false, &single_use1_p);
528 if (!def_stmt || !can_propagate_from (def_stmt))
529 return did_something;
531 rhs1 = rhs_to_tree (TREE_TYPE (op0), def_stmt);
532 tmp = combine_cond_expr_cond (loc, TREE_CODE (cond),
534 op0, rhs1, !single_use1_p);
536 /* If that wasn't successful either, try both operands. */
539 && rhs1 != NULL_TREE)
540 tmp = combine_cond_expr_cond (loc, TREE_CODE (cond),
543 fold_convert_loc (loc,
546 !(single_use0_p && single_use1_p));
548 else if (TREE_CODE (cond) == SSA_NAME)
551 def_stmt = get_prop_source_stmt (name, true, NULL);
552 if (def_stmt || !can_propagate_from (def_stmt))
553 return did_something;
555 rhs0 = gimple_assign_rhs1 (def_stmt);
556 tmp = combine_cond_expr_cond (loc, NE_EXPR, boolean_type_node, rhs0,
557 build_int_cst (TREE_TYPE (rhs0), 0),
563 if (dump_file && tmp)
565 fprintf (dump_file, " Replaced '");
566 print_generic_expr (dump_file, cond, 0);
567 fprintf (dump_file, "' with '");
568 print_generic_expr (dump_file, tmp, 0);
569 fprintf (dump_file, "'\n");
572 gimple_assign_set_rhs_from_tree (gsi_p, unshare_expr (tmp));
573 stmt = gsi_stmt (*gsi_p);
576 /* Remove defining statements. */
577 if (remove_prop_source_from_use (name)
578 || is_gimple_min_invariant (tmp))
580 else if (did_something == 0)
583 /* Continue combining. */
590 return did_something;
593 /* We've just substituted an ADDR_EXPR into stmt. Update all the
594 relevant data structures to match. */
597 tidy_after_forward_propagate_addr (gimple stmt)
599 /* We may have turned a trapping insn into a non-trapping insn. */
600 if (maybe_clean_or_replace_eh_stmt (stmt, stmt)
601 && gimple_purge_dead_eh_edges (gimple_bb (stmt)))
604 if (TREE_CODE (gimple_assign_rhs1 (stmt)) == ADDR_EXPR)
605 recompute_tree_invariant_for_addr_expr (gimple_assign_rhs1 (stmt));
608 /* DEF_RHS contains the address of the 0th element in an array.
609 USE_STMT uses type of DEF_RHS to compute the address of an
610 arbitrary element within the array. The (variable) byte offset
611 of the element is contained in OFFSET.
613 We walk back through the use-def chains of OFFSET to verify that
614 it is indeed computing the offset of an element within the array
615 and extract the index corresponding to the given byte offset.
617 We then try to fold the entire address expression into a form
620 If we are successful, we replace the right hand side of USE_STMT
621 with the new address computation. */
624 forward_propagate_addr_into_variable_array_index (tree offset,
626 gimple_stmt_iterator *use_stmt_gsi)
629 gimple offset_def, use_stmt = gsi_stmt (*use_stmt_gsi);
632 if (TREE_CODE (TREE_OPERAND (def_rhs, 0)) == ARRAY_REF)
633 tunit = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (def_rhs)));
634 else if (TREE_CODE (TREE_TYPE (TREE_OPERAND (def_rhs, 0))) == ARRAY_TYPE)
635 tunit = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (TREE_TYPE (def_rhs))));
638 if (!host_integerp (tunit, 1))
641 /* Get the offset's defining statement. */
642 offset_def = SSA_NAME_DEF_STMT (offset);
644 /* Try to find an expression for a proper index. This is either a
645 multiplication expression by the element size or just the ssa name we came
646 along in case the element size is one. In that case, however, we do not
647 allow multiplications because they can be computing index to a higher
648 level dimension (PR 37861). */
649 if (integer_onep (tunit))
651 if (is_gimple_assign (offset_def)
652 && gimple_assign_rhs_code (offset_def) == MULT_EXPR)
659 /* The statement which defines OFFSET before type conversion
660 must be a simple GIMPLE_ASSIGN. */
661 if (!is_gimple_assign (offset_def))
664 /* The RHS of the statement which defines OFFSET must be a
665 multiplication of an object by the size of the array elements.
666 This implicitly verifies that the size of the array elements
668 if (gimple_assign_rhs_code (offset_def) == MULT_EXPR
669 && TREE_CODE (gimple_assign_rhs2 (offset_def)) == INTEGER_CST
670 && tree_int_cst_equal (gimple_assign_rhs2 (offset_def), tunit))
672 /* The first operand to the MULT_EXPR is the desired index. */
673 index = gimple_assign_rhs1 (offset_def);
675 /* If we have idx * tunit + CST * tunit re-associate that. */
676 else if ((gimple_assign_rhs_code (offset_def) == PLUS_EXPR
677 || gimple_assign_rhs_code (offset_def) == MINUS_EXPR)
678 && TREE_CODE (gimple_assign_rhs1 (offset_def)) == SSA_NAME
679 && TREE_CODE (gimple_assign_rhs2 (offset_def)) == INTEGER_CST
680 && (tmp = div_if_zero_remainder (EXACT_DIV_EXPR,
681 gimple_assign_rhs2 (offset_def),
682 tunit)) != NULL_TREE)
684 gimple offset_def2 = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (offset_def));
685 if (is_gimple_assign (offset_def2)
686 && gimple_assign_rhs_code (offset_def2) == MULT_EXPR
687 && TREE_CODE (gimple_assign_rhs2 (offset_def2)) == INTEGER_CST
688 && tree_int_cst_equal (gimple_assign_rhs2 (offset_def2), tunit))
690 index = fold_build2 (gimple_assign_rhs_code (offset_def),
692 gimple_assign_rhs1 (offset_def2), tmp);
701 /* Replace the pointer addition with array indexing. */
702 index = force_gimple_operand_gsi (use_stmt_gsi, index, true, NULL_TREE,
703 true, GSI_SAME_STMT);
704 if (TREE_CODE (TREE_OPERAND (def_rhs, 0)) == ARRAY_REF)
706 new_rhs = unshare_expr (def_rhs);
707 TREE_OPERAND (TREE_OPERAND (new_rhs, 0), 1) = index;
711 new_rhs = build4 (ARRAY_REF, TREE_TYPE (TREE_TYPE (TREE_TYPE (def_rhs))),
712 unshare_expr (TREE_OPERAND (def_rhs, 0)),
713 index, integer_zero_node, NULL_TREE);
714 new_rhs = build_fold_addr_expr (new_rhs);
715 if (!useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (use_stmt)),
716 TREE_TYPE (new_rhs)))
718 new_rhs = force_gimple_operand_gsi (use_stmt_gsi, new_rhs, true,
719 NULL_TREE, true, GSI_SAME_STMT);
720 new_rhs = fold_convert (TREE_TYPE (gimple_assign_lhs (use_stmt)),
724 gimple_assign_set_rhs_from_tree (use_stmt_gsi, new_rhs);
725 use_stmt = gsi_stmt (*use_stmt_gsi);
727 /* That should have created gimple, so there is no need to
728 record information to undo the propagation. */
729 fold_stmt_inplace (use_stmt);
730 tidy_after_forward_propagate_addr (use_stmt);
734 /* NAME is a SSA_NAME representing DEF_RHS which is of the form
735 ADDR_EXPR <whatever>.
737 Try to forward propagate the ADDR_EXPR into the use USE_STMT.
738 Often this will allow for removal of an ADDR_EXPR and INDIRECT_REF
739 node or for recovery of array indexing from pointer arithmetic.
741 Return true if the propagation was successful (the propagation can
742 be not totally successful, yet things may have been changed). */
745 forward_propagate_addr_expr_1 (tree name, tree def_rhs,
746 gimple_stmt_iterator *use_stmt_gsi,
749 tree lhs, rhs, rhs2, array_ref;
750 gimple use_stmt = gsi_stmt (*use_stmt_gsi);
751 enum tree_code rhs_code;
754 gcc_assert (TREE_CODE (def_rhs) == ADDR_EXPR);
756 lhs = gimple_assign_lhs (use_stmt);
757 rhs_code = gimple_assign_rhs_code (use_stmt);
758 rhs = gimple_assign_rhs1 (use_stmt);
760 /* Trivial cases. The use statement could be a trivial copy or a
761 useless conversion. Recurse to the uses of the lhs as copyprop does
762 not copy through different variant pointers and FRE does not catch
763 all useless conversions. Treat the case of a single-use name and
764 a conversion to def_rhs type separate, though. */
765 if (TREE_CODE (lhs) == SSA_NAME
766 && ((rhs_code == SSA_NAME && rhs == name)
767 || CONVERT_EXPR_CODE_P (rhs_code)))
769 /* Only recurse if we don't deal with a single use or we cannot
770 do the propagation to the current statement. In particular
771 we can end up with a conversion needed for a non-invariant
772 address which we cannot do in a single statement. */
774 || (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (def_rhs))
775 && (!is_gimple_min_invariant (def_rhs)
776 || (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
777 && POINTER_TYPE_P (TREE_TYPE (def_rhs))
778 && (TYPE_PRECISION (TREE_TYPE (lhs))
779 > TYPE_PRECISION (TREE_TYPE (def_rhs)))))))
780 return forward_propagate_addr_expr (lhs, def_rhs);
782 gimple_assign_set_rhs1 (use_stmt, unshare_expr (def_rhs));
783 if (useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (def_rhs)))
784 gimple_assign_set_rhs_code (use_stmt, TREE_CODE (def_rhs));
786 gimple_assign_set_rhs_code (use_stmt, NOP_EXPR);
790 /* Propagate through constant pointer adjustments. */
791 if (TREE_CODE (lhs) == SSA_NAME
792 && rhs_code == POINTER_PLUS_EXPR
794 && TREE_CODE (gimple_assign_rhs2 (use_stmt)) == INTEGER_CST)
797 /* As we come here with non-invariant addresses in def_rhs we need
798 to make sure we can build a valid constant offsetted address
799 for further propagation. Simply rely on fold building that
800 and check after the fact. */
801 new_def_rhs = fold_build2 (MEM_REF, TREE_TYPE (TREE_TYPE (rhs)),
803 fold_convert (ptr_type_node,
804 gimple_assign_rhs2 (use_stmt)));
805 if (TREE_CODE (new_def_rhs) == MEM_REF
806 && !is_gimple_mem_ref_addr (TREE_OPERAND (new_def_rhs, 0)))
808 new_def_rhs = build_fold_addr_expr_with_type (new_def_rhs,
811 /* Recurse. If we could propagate into all uses of lhs do not
812 bother to replace into the current use but just pretend we did. */
813 if (TREE_CODE (new_def_rhs) == ADDR_EXPR
814 && forward_propagate_addr_expr (lhs, new_def_rhs))
817 if (useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (new_def_rhs)))
818 gimple_assign_set_rhs_with_ops (use_stmt_gsi, TREE_CODE (new_def_rhs),
819 new_def_rhs, NULL_TREE);
820 else if (is_gimple_min_invariant (new_def_rhs))
821 gimple_assign_set_rhs_with_ops (use_stmt_gsi, NOP_EXPR,
822 new_def_rhs, NULL_TREE);
825 gcc_assert (gsi_stmt (*use_stmt_gsi) == use_stmt);
826 update_stmt (use_stmt);
830 /* Now strip away any outer COMPONENT_REF/ARRAY_REF nodes from the LHS.
831 ADDR_EXPR will not appear on the LHS. */
832 lhs = gimple_assign_lhs (use_stmt);
833 while (handled_component_p (lhs))
834 lhs = TREE_OPERAND (lhs, 0);
836 /* Now see if the LHS node is a MEM_REF using NAME. If so,
837 propagate the ADDR_EXPR into the use of NAME and fold the result. */
838 if (TREE_CODE (lhs) == MEM_REF
839 && TREE_OPERAND (lhs, 0) == name)
842 HOST_WIDE_INT def_rhs_offset;
843 /* If the address is invariant we can always fold it. */
844 if ((def_rhs_base = get_addr_base_and_unit_offset (TREE_OPERAND (def_rhs, 0),
847 double_int off = mem_ref_offset (lhs);
849 off = double_int_add (off,
850 shwi_to_double_int (def_rhs_offset));
851 if (TREE_CODE (def_rhs_base) == MEM_REF)
853 off = double_int_add (off, mem_ref_offset (def_rhs_base));
854 new_ptr = TREE_OPERAND (def_rhs_base, 0);
857 new_ptr = build_fold_addr_expr (def_rhs_base);
858 TREE_OPERAND (lhs, 0) = new_ptr;
859 TREE_OPERAND (lhs, 1)
860 = double_int_to_tree (TREE_TYPE (TREE_OPERAND (lhs, 1)), off);
861 tidy_after_forward_propagate_addr (use_stmt);
862 /* Continue propagating into the RHS if this was not the only use. */
866 /* If the LHS is a plain dereference and the value type is the same as
867 that of the pointed-to type of the address we can put the
868 dereferenced address on the LHS preserving the original alias-type. */
869 else if (gimple_assign_lhs (use_stmt) == lhs
870 && useless_type_conversion_p
871 (TREE_TYPE (TREE_OPERAND (def_rhs, 0)),
872 TREE_TYPE (gimple_assign_rhs1 (use_stmt))))
874 tree *def_rhs_basep = &TREE_OPERAND (def_rhs, 0);
875 tree new_offset, new_base, saved, new_lhs;
876 while (handled_component_p (*def_rhs_basep))
877 def_rhs_basep = &TREE_OPERAND (*def_rhs_basep, 0);
878 saved = *def_rhs_basep;
879 if (TREE_CODE (*def_rhs_basep) == MEM_REF)
881 new_base = TREE_OPERAND (*def_rhs_basep, 0);
883 = int_const_binop (PLUS_EXPR, TREE_OPERAND (lhs, 1),
884 TREE_OPERAND (*def_rhs_basep, 1), 0);
888 new_base = build_fold_addr_expr (*def_rhs_basep);
889 new_offset = TREE_OPERAND (lhs, 1);
891 *def_rhs_basep = build2 (MEM_REF, TREE_TYPE (*def_rhs_basep),
892 new_base, new_offset);
893 TREE_THIS_VOLATILE (*def_rhs_basep) = TREE_THIS_VOLATILE (lhs);
894 TREE_SIDE_EFFECTS (*def_rhs_basep) = TREE_SIDE_EFFECTS (lhs);
895 TREE_THIS_NOTRAP (*def_rhs_basep) = TREE_THIS_NOTRAP (lhs);
896 new_lhs = unshare_expr (TREE_OPERAND (def_rhs, 0));
897 gimple_assign_set_lhs (use_stmt, new_lhs);
898 TREE_THIS_VOLATILE (new_lhs) = TREE_THIS_VOLATILE (lhs);
899 TREE_SIDE_EFFECTS (new_lhs) = TREE_SIDE_EFFECTS (lhs);
900 *def_rhs_basep = saved;
901 tidy_after_forward_propagate_addr (use_stmt);
902 /* Continue propagating into the RHS if this was not the
908 /* We can have a struct assignment dereferencing our name twice.
909 Note that we didn't propagate into the lhs to not falsely
910 claim we did when propagating into the rhs. */
914 /* Strip away any outer COMPONENT_REF, ARRAY_REF or ADDR_EXPR
915 nodes from the RHS. */
916 rhs = gimple_assign_rhs1 (use_stmt);
917 if (TREE_CODE (rhs) == ADDR_EXPR)
918 rhs = TREE_OPERAND (rhs, 0);
919 while (handled_component_p (rhs))
920 rhs = TREE_OPERAND (rhs, 0);
922 /* Now see if the RHS node is a MEM_REF using NAME. If so,
923 propagate the ADDR_EXPR into the use of NAME and fold the result. */
924 if (TREE_CODE (rhs) == MEM_REF
925 && TREE_OPERAND (rhs, 0) == name)
928 HOST_WIDE_INT def_rhs_offset;
929 if ((def_rhs_base = get_addr_base_and_unit_offset (TREE_OPERAND (def_rhs, 0),
932 double_int off = mem_ref_offset (rhs);
934 off = double_int_add (off,
935 shwi_to_double_int (def_rhs_offset));
936 if (TREE_CODE (def_rhs_base) == MEM_REF)
938 off = double_int_add (off, mem_ref_offset (def_rhs_base));
939 new_ptr = TREE_OPERAND (def_rhs_base, 0);
942 new_ptr = build_fold_addr_expr (def_rhs_base);
943 TREE_OPERAND (rhs, 0) = new_ptr;
944 TREE_OPERAND (rhs, 1)
945 = double_int_to_tree (TREE_TYPE (TREE_OPERAND (rhs, 1)), off);
946 fold_stmt_inplace (use_stmt);
947 tidy_after_forward_propagate_addr (use_stmt);
950 /* If the RHS is a plain dereference and the value type is the same as
951 that of the pointed-to type of the address we can put the
952 dereferenced address on the RHS preserving the original alias-type. */
953 else if (gimple_assign_rhs1 (use_stmt) == rhs
954 && useless_type_conversion_p
955 (TREE_TYPE (gimple_assign_lhs (use_stmt)),
956 TREE_TYPE (TREE_OPERAND (def_rhs, 0))))
958 tree *def_rhs_basep = &TREE_OPERAND (def_rhs, 0);
959 tree new_offset, new_base, saved, new_rhs;
960 while (handled_component_p (*def_rhs_basep))
961 def_rhs_basep = &TREE_OPERAND (*def_rhs_basep, 0);
962 saved = *def_rhs_basep;
963 if (TREE_CODE (*def_rhs_basep) == MEM_REF)
965 new_base = TREE_OPERAND (*def_rhs_basep, 0);
967 = int_const_binop (PLUS_EXPR, TREE_OPERAND (rhs, 1),
968 TREE_OPERAND (*def_rhs_basep, 1), 0);
972 new_base = build_fold_addr_expr (*def_rhs_basep);
973 new_offset = TREE_OPERAND (rhs, 1);
975 *def_rhs_basep = build2 (MEM_REF, TREE_TYPE (*def_rhs_basep),
976 new_base, new_offset);
977 TREE_THIS_VOLATILE (*def_rhs_basep) = TREE_THIS_VOLATILE (rhs);
978 TREE_SIDE_EFFECTS (*def_rhs_basep) = TREE_SIDE_EFFECTS (rhs);
979 TREE_THIS_NOTRAP (*def_rhs_basep) = TREE_THIS_NOTRAP (rhs);
980 new_rhs = unshare_expr (TREE_OPERAND (def_rhs, 0));
981 gimple_assign_set_rhs1 (use_stmt, new_rhs);
982 TREE_THIS_VOLATILE (new_rhs) = TREE_THIS_VOLATILE (rhs);
983 TREE_SIDE_EFFECTS (new_rhs) = TREE_SIDE_EFFECTS (rhs);
984 *def_rhs_basep = saved;
985 fold_stmt_inplace (use_stmt);
986 tidy_after_forward_propagate_addr (use_stmt);
991 /* If the use of the ADDR_EXPR is not a POINTER_PLUS_EXPR, there
993 if (gimple_assign_rhs_code (use_stmt) != POINTER_PLUS_EXPR
994 || gimple_assign_rhs1 (use_stmt) != name)
997 /* The remaining cases are all for turning pointer arithmetic into
998 array indexing. They only apply when we have the address of
999 element zero in an array. If that is not the case then there
1000 is nothing to do. */
1001 array_ref = TREE_OPERAND (def_rhs, 0);
1002 if ((TREE_CODE (array_ref) != ARRAY_REF
1003 || TREE_CODE (TREE_TYPE (TREE_OPERAND (array_ref, 0))) != ARRAY_TYPE
1004 || TREE_CODE (TREE_OPERAND (array_ref, 1)) != INTEGER_CST)
1005 && TREE_CODE (TREE_TYPE (array_ref)) != ARRAY_TYPE)
1008 rhs2 = gimple_assign_rhs2 (use_stmt);
1009 /* Try to optimize &x[C1] p+ C2 where C2 is a multiple of the size
1010 of the elements in X into &x[C1 + C2/element size]. */
1011 if (TREE_CODE (rhs2) == INTEGER_CST)
1013 tree new_rhs = maybe_fold_stmt_addition (gimple_location (use_stmt),
1014 TREE_TYPE (def_rhs),
1018 tree type = TREE_TYPE (gimple_assign_lhs (use_stmt));
1019 new_rhs = unshare_expr (new_rhs);
1020 if (!useless_type_conversion_p (type, TREE_TYPE (new_rhs)))
1022 if (!is_gimple_min_invariant (new_rhs))
1023 new_rhs = force_gimple_operand_gsi (use_stmt_gsi, new_rhs,
1025 true, GSI_SAME_STMT);
1026 new_rhs = fold_convert (type, new_rhs);
1028 gimple_assign_set_rhs_from_tree (use_stmt_gsi, new_rhs);
1029 use_stmt = gsi_stmt (*use_stmt_gsi);
1030 update_stmt (use_stmt);
1031 tidy_after_forward_propagate_addr (use_stmt);
1036 /* Try to optimize &x[0] p+ OFFSET where OFFSET is defined by
1037 converting a multiplication of an index by the size of the
1038 array elements, then the result is converted into the proper
1039 type for the arithmetic. */
1040 if (TREE_CODE (rhs2) == SSA_NAME
1041 && (TREE_CODE (array_ref) != ARRAY_REF
1042 || integer_zerop (TREE_OPERAND (array_ref, 1)))
1043 && useless_type_conversion_p (TREE_TYPE (name), TREE_TYPE (def_rhs))
1044 /* Avoid problems with IVopts creating PLUS_EXPRs with a
1045 different type than their operands. */
1046 && useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (def_rhs)))
1047 return forward_propagate_addr_into_variable_array_index (rhs2, def_rhs,
1052 /* STMT is a statement of the form SSA_NAME = ADDR_EXPR <whatever>.
1054 Try to forward propagate the ADDR_EXPR into all uses of the SSA_NAME.
1055 Often this will allow for removal of an ADDR_EXPR and INDIRECT_REF
1056 node or for recovery of array indexing from pointer arithmetic.
1057 Returns true, if all uses have been propagated into. */
1060 forward_propagate_addr_expr (tree name, tree rhs)
1062 int stmt_loop_depth = gimple_bb (SSA_NAME_DEF_STMT (name))->loop_depth;
1063 imm_use_iterator iter;
1066 bool single_use_p = has_single_use (name);
1068 FOR_EACH_IMM_USE_STMT (use_stmt, iter, name)
1073 /* If the use is not in a simple assignment statement, then
1074 there is nothing we can do. */
1075 if (gimple_code (use_stmt) != GIMPLE_ASSIGN)
1077 if (!is_gimple_debug (use_stmt))
1082 /* If the use is in a deeper loop nest, then we do not want
1083 to propagate non-invariant ADDR_EXPRs into the loop as that
1084 is likely adding expression evaluations into the loop. */
1085 if (gimple_bb (use_stmt)->loop_depth > stmt_loop_depth
1086 && !is_gimple_min_invariant (rhs))
1093 gimple_stmt_iterator gsi = gsi_for_stmt (use_stmt);
1094 result = forward_propagate_addr_expr_1 (name, rhs, &gsi,
1096 /* If the use has moved to a different statement adjust
1097 the update machinery for the old statement too. */
1098 if (use_stmt != gsi_stmt (gsi))
1100 update_stmt (use_stmt);
1101 use_stmt = gsi_stmt (gsi);
1104 update_stmt (use_stmt);
1108 /* Remove intermediate now unused copy and conversion chains. */
1109 use_rhs = gimple_assign_rhs1 (use_stmt);
1111 && TREE_CODE (gimple_assign_lhs (use_stmt)) == SSA_NAME
1112 && TREE_CODE (use_rhs) == SSA_NAME
1113 && has_zero_uses (gimple_assign_lhs (use_stmt)))
1115 gimple_stmt_iterator gsi = gsi_for_stmt (use_stmt);
1116 release_defs (use_stmt);
1117 gsi_remove (&gsi, true);
1121 return all && has_zero_uses (name);
1124 /* Forward propagate the comparison defined in STMT like
1125 cond_1 = x CMP y to uses of the form
1129 Returns true if stmt is now unused. */
1132 forward_propagate_comparison (gimple stmt)
1134 tree name = gimple_assign_lhs (stmt);
1136 tree tmp = NULL_TREE;
1138 /* Don't propagate ssa names that occur in abnormal phis. */
1139 if ((TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
1140 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_assign_rhs1 (stmt)))
1141 || (TREE_CODE (gimple_assign_rhs2 (stmt)) == SSA_NAME
1142 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_assign_rhs2 (stmt))))
1145 /* Do not un-cse comparisons. But propagate through copies. */
1146 use_stmt = get_prop_dest_stmt (name, &name);
1150 /* Conversion of the condition result to another integral type. */
1151 if (is_gimple_assign (use_stmt)
1152 && (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (use_stmt))
1153 || TREE_CODE_CLASS (gimple_assign_rhs_code (use_stmt))
1155 || gimple_assign_rhs_code (use_stmt) == TRUTH_NOT_EXPR)
1156 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_lhs (use_stmt))))
1158 tree lhs = gimple_assign_lhs (use_stmt);
1160 /* We can propagate the condition into a conversion. */
1161 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (use_stmt)))
1163 /* Avoid using fold here as that may create a COND_EXPR with
1164 non-boolean condition as canonical form. */
1165 tmp = build2 (gimple_assign_rhs_code (stmt), TREE_TYPE (lhs),
1166 gimple_assign_rhs1 (stmt), gimple_assign_rhs2 (stmt));
1168 /* We can propagate the condition into X op CST where op
1169 is EQ_EXPR or NE_EXPR and CST is either one or zero. */
1170 else if (TREE_CODE_CLASS (gimple_assign_rhs_code (use_stmt))
1172 && TREE_CODE (gimple_assign_rhs1 (use_stmt)) == SSA_NAME
1173 && TREE_CODE (gimple_assign_rhs2 (use_stmt)) == INTEGER_CST)
1175 enum tree_code code = gimple_assign_rhs_code (use_stmt);
1176 tree cst = gimple_assign_rhs2 (use_stmt);
1179 cond = build2 (gimple_assign_rhs_code (stmt),
1181 gimple_assign_rhs1 (stmt),
1182 gimple_assign_rhs2 (stmt));
1184 tmp = combine_cond_expr_cond (gimple_location (use_stmt),
1185 code, TREE_TYPE (lhs),
1187 if (tmp == NULL_TREE)
1190 /* We can propagate the condition into a statement that
1191 computes the logical negation of the comparison result. */
1192 else if (gimple_assign_rhs_code (use_stmt) == TRUTH_NOT_EXPR)
1194 tree type = TREE_TYPE (gimple_assign_rhs1 (stmt));
1195 bool nans = HONOR_NANS (TYPE_MODE (type));
1196 enum tree_code code;
1197 code = invert_tree_comparison (gimple_assign_rhs_code (stmt), nans);
1198 if (code == ERROR_MARK)
1201 tmp = build2 (code, TREE_TYPE (lhs), gimple_assign_rhs1 (stmt),
1202 gimple_assign_rhs2 (stmt));
1208 gimple_stmt_iterator gsi = gsi_for_stmt (use_stmt);
1209 gimple_assign_set_rhs_from_tree (&gsi, unshare_expr (tmp));
1210 use_stmt = gsi_stmt (gsi);
1211 update_stmt (use_stmt);
1214 if (dump_file && (dump_flags & TDF_DETAILS))
1216 tree old_rhs = rhs_to_tree (TREE_TYPE (gimple_assign_lhs (stmt)),
1218 fprintf (dump_file, " Replaced '");
1219 print_generic_expr (dump_file, old_rhs, dump_flags);
1220 fprintf (dump_file, "' with '");
1221 print_generic_expr (dump_file, tmp, dump_flags);
1222 fprintf (dump_file, "'\n");
1225 /* Remove defining statements. */
1226 return remove_prop_source_from_use (name);
1232 /* If we have lhs = ~x (STMT), look and see if earlier we had x = ~y.
1233 If so, we can change STMT into lhs = y which can later be copy
1234 propagated. Similarly for negation.
1236 This could trivially be formulated as a forward propagation
1237 to immediate uses. However, we already had an implementation
1238 from DOM which used backward propagation via the use-def links.
1240 It turns out that backward propagation is actually faster as
1241 there's less work to do for each NOT/NEG expression we find.
1242 Backwards propagation needs to look at the statement in a single
1243 backlink. Forward propagation needs to look at potentially more
1244 than one forward link. */
1247 simplify_not_neg_expr (gimple_stmt_iterator *gsi_p)
1249 gimple stmt = gsi_stmt (*gsi_p);
1250 tree rhs = gimple_assign_rhs1 (stmt);
1251 gimple rhs_def_stmt = SSA_NAME_DEF_STMT (rhs);
1253 /* See if the RHS_DEF_STMT has the same form as our statement. */
1254 if (is_gimple_assign (rhs_def_stmt)
1255 && gimple_assign_rhs_code (rhs_def_stmt) == gimple_assign_rhs_code (stmt))
1257 tree rhs_def_operand = gimple_assign_rhs1 (rhs_def_stmt);
1259 /* Verify that RHS_DEF_OPERAND is a suitable SSA_NAME. */
1260 if (TREE_CODE (rhs_def_operand) == SSA_NAME
1261 && ! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs_def_operand))
1263 gimple_assign_set_rhs_from_tree (gsi_p, rhs_def_operand);
1264 stmt = gsi_stmt (*gsi_p);
1270 /* STMT is a SWITCH_EXPR for which we attempt to find equivalent forms of
1271 the condition which we may be able to optimize better. */
1274 simplify_gimple_switch (gimple stmt)
1276 tree cond = gimple_switch_index (stmt);
1280 /* The optimization that we really care about is removing unnecessary
1281 casts. That will let us do much better in propagating the inferred
1282 constant at the switch target. */
1283 if (TREE_CODE (cond) == SSA_NAME)
1285 def_stmt = SSA_NAME_DEF_STMT (cond);
1286 if (is_gimple_assign (def_stmt))
1288 if (gimple_assign_rhs_code (def_stmt) == NOP_EXPR)
1293 def = gimple_assign_rhs1 (def_stmt);
1295 /* ??? Why was Jeff testing this? We are gimple... */
1296 gcc_checking_assert (is_gimple_val (def));
1298 to = TREE_TYPE (cond);
1299 ti = TREE_TYPE (def);
1301 /* If we have an extension that preserves value, then we
1302 can copy the source value into the switch. */
1304 need_precision = TYPE_PRECISION (ti);
1306 if (! INTEGRAL_TYPE_P (ti))
1308 else if (TYPE_UNSIGNED (to) && !TYPE_UNSIGNED (ti))
1310 else if (!TYPE_UNSIGNED (to) && TYPE_UNSIGNED (ti))
1311 need_precision += 1;
1312 if (TYPE_PRECISION (to) < need_precision)
1317 gimple_switch_set_index (stmt, def);
1325 /* For pointers p2 and p1 return p2 - p1 if the
1326 difference is known and constant, otherwise return NULL. */
1329 constant_pointer_difference (tree p1, tree p2)
1332 #define CPD_ITERATIONS 5
1333 tree exps[2][CPD_ITERATIONS];
1334 tree offs[2][CPD_ITERATIONS];
1337 for (i = 0; i < 2; i++)
1339 tree p = i ? p1 : p2;
1340 tree off = size_zero_node;
1342 enum tree_code code;
1344 /* For each of p1 and p2 we need to iterate at least
1345 twice, to handle ADDR_EXPR directly in p1/p2,
1346 SSA_NAME with ADDR_EXPR or POINTER_PLUS_EXPR etc.
1347 on definition's stmt RHS. Iterate a few extra times. */
1351 if (!POINTER_TYPE_P (TREE_TYPE (p)))
1353 if (TREE_CODE (p) == ADDR_EXPR)
1355 tree q = TREE_OPERAND (p, 0);
1356 HOST_WIDE_INT offset;
1357 tree base = get_addr_base_and_unit_offset (q, &offset);
1362 off = size_binop (PLUS_EXPR, off, size_int (offset));
1364 if (TREE_CODE (q) == MEM_REF
1365 && TREE_CODE (TREE_OPERAND (q, 0)) == SSA_NAME)
1367 p = TREE_OPERAND (q, 0);
1368 off = size_binop (PLUS_EXPR, off,
1369 double_int_to_tree (sizetype,
1370 mem_ref_offset (q)));
1379 if (TREE_CODE (p) != SSA_NAME)
1383 if (j == CPD_ITERATIONS)
1385 stmt = SSA_NAME_DEF_STMT (p);
1386 if (!is_gimple_assign (stmt) || gimple_assign_lhs (stmt) != p)
1388 code = gimple_assign_rhs_code (stmt);
1389 if (code == POINTER_PLUS_EXPR)
1391 if (TREE_CODE (gimple_assign_rhs2 (stmt)) != INTEGER_CST)
1393 off = size_binop (PLUS_EXPR, off, gimple_assign_rhs2 (stmt));
1394 p = gimple_assign_rhs1 (stmt);
1396 else if (code == ADDR_EXPR || code == NOP_EXPR)
1397 p = gimple_assign_rhs1 (stmt);
1405 for (i = 0; i < cnt[0]; i++)
1406 for (j = 0; j < cnt[1]; j++)
1407 if (exps[0][i] == exps[1][j])
1408 return size_binop (MINUS_EXPR, offs[0][i], offs[1][j]);
1413 /* *GSI_P is a GIMPLE_CALL to a builtin function.
1415 memcpy (p, "abcd", 4);
1416 memset (p + 4, ' ', 3);
1418 memcpy (p, "abcd ", 7);
1419 call if the latter can be stored by pieces during expansion. */
1422 simplify_builtin_call (gimple_stmt_iterator *gsi_p, tree callee2)
1424 gimple stmt1, stmt2 = gsi_stmt (*gsi_p);
1425 tree vuse = gimple_vuse (stmt2);
1428 stmt1 = SSA_NAME_DEF_STMT (vuse);
1430 switch (DECL_FUNCTION_CODE (callee2))
1432 case BUILT_IN_MEMSET:
1433 if (gimple_call_num_args (stmt2) != 3
1434 || gimple_call_lhs (stmt2)
1436 || BITS_PER_UNIT != 8)
1441 tree ptr1, src1, str1, off1, len1, lhs1;
1442 tree ptr2 = gimple_call_arg (stmt2, 0);
1443 tree val2 = gimple_call_arg (stmt2, 1);
1444 tree len2 = gimple_call_arg (stmt2, 2);
1445 tree diff, vdef, new_str_cst;
1447 unsigned int ptr1_align;
1448 unsigned HOST_WIDE_INT src_len;
1450 use_operand_p use_p;
1452 if (!host_integerp (val2, 0)
1453 || !host_integerp (len2, 1))
1455 if (is_gimple_call (stmt1))
1457 /* If first stmt is a call, it needs to be memcpy
1458 or mempcpy, with string literal as second argument and
1460 callee1 = gimple_call_fndecl (stmt1);
1461 if (callee1 == NULL_TREE
1462 || DECL_BUILT_IN_CLASS (callee1) != BUILT_IN_NORMAL
1463 || gimple_call_num_args (stmt1) != 3)
1465 if (DECL_FUNCTION_CODE (callee1) != BUILT_IN_MEMCPY
1466 && DECL_FUNCTION_CODE (callee1) != BUILT_IN_MEMPCPY)
1468 ptr1 = gimple_call_arg (stmt1, 0);
1469 src1 = gimple_call_arg (stmt1, 1);
1470 len1 = gimple_call_arg (stmt1, 2);
1471 lhs1 = gimple_call_lhs (stmt1);
1472 if (!host_integerp (len1, 1))
1474 str1 = string_constant (src1, &off1);
1475 if (str1 == NULL_TREE)
1477 if (!host_integerp (off1, 1)
1478 || compare_tree_int (off1, TREE_STRING_LENGTH (str1) - 1) > 0
1479 || compare_tree_int (len1, TREE_STRING_LENGTH (str1)
1480 - tree_low_cst (off1, 1)) > 0
1481 || TREE_CODE (TREE_TYPE (str1)) != ARRAY_TYPE
1482 || TYPE_MODE (TREE_TYPE (TREE_TYPE (str1)))
1483 != TYPE_MODE (char_type_node))
1486 else if (gimple_assign_single_p (stmt1))
1488 /* Otherwise look for length 1 memcpy optimized into
1490 ptr1 = gimple_assign_lhs (stmt1);
1491 src1 = gimple_assign_rhs1 (stmt1);
1492 if (TREE_CODE (ptr1) != MEM_REF
1493 || TYPE_MODE (TREE_TYPE (ptr1)) != TYPE_MODE (char_type_node)
1494 || !host_integerp (src1, 0))
1496 ptr1 = build_fold_addr_expr (ptr1);
1497 callee1 = NULL_TREE;
1498 len1 = size_one_node;
1500 off1 = size_zero_node;
1506 diff = constant_pointer_difference (ptr1, ptr2);
1507 if (diff == NULL && lhs1 != NULL)
1509 diff = constant_pointer_difference (lhs1, ptr2);
1510 if (DECL_FUNCTION_CODE (callee1) == BUILT_IN_MEMPCPY
1512 diff = size_binop (PLUS_EXPR, diff,
1513 fold_convert (sizetype, len1));
1515 /* If the difference between the second and first destination pointer
1516 is not constant, or is bigger than memcpy length, bail out. */
1518 || !host_integerp (diff, 1)
1519 || tree_int_cst_lt (len1, diff))
1522 /* Use maximum of difference plus memset length and memcpy length
1523 as the new memcpy length, if it is too big, bail out. */
1524 src_len = tree_low_cst (diff, 1);
1525 src_len += tree_low_cst (len2, 1);
1526 if (src_len < (unsigned HOST_WIDE_INT) tree_low_cst (len1, 1))
1527 src_len = tree_low_cst (len1, 1);
1531 /* If mempcpy value is used elsewhere, bail out, as mempcpy
1532 with bigger length will return different result. */
1533 if (lhs1 != NULL_TREE
1534 && DECL_FUNCTION_CODE (callee1) == BUILT_IN_MEMPCPY
1535 && (TREE_CODE (lhs1) != SSA_NAME
1536 || !single_imm_use (lhs1, &use_p, &use_stmt)
1537 || use_stmt != stmt2))
1540 /* If anything reads memory in between memcpy and memset
1541 call, the modified memcpy call might change it. */
1542 vdef = gimple_vdef (stmt1);
1544 && (!single_imm_use (vdef, &use_p, &use_stmt)
1545 || use_stmt != stmt2))
1548 ptr1_align = get_pointer_alignment (ptr1, BIGGEST_ALIGNMENT);
1549 /* Construct the new source string literal. */
1550 src_buf = XALLOCAVEC (char, src_len + 1);
1553 TREE_STRING_POINTER (str1) + tree_low_cst (off1, 1),
1554 tree_low_cst (len1, 1));
1556 src_buf[0] = tree_low_cst (src1, 0);
1557 memset (src_buf + tree_low_cst (diff, 1),
1558 tree_low_cst (val2, 1), tree_low_cst (len2, 1));
1559 src_buf[src_len] = '\0';
1560 /* Neither builtin_strncpy_read_str nor builtin_memcpy_read_str
1561 handle embedded '\0's. */
1562 if (strlen (src_buf) != src_len)
1564 rtl_profile_for_bb (gimple_bb (stmt2));
1565 /* If the new memcpy wouldn't be emitted by storing the literal
1566 by pieces, this optimization might enlarge .rodata too much,
1567 as commonly used string literals couldn't be shared any
1569 if (!can_store_by_pieces (src_len,
1570 builtin_strncpy_read_str,
1571 src_buf, ptr1_align, false))
1574 new_str_cst = build_string_literal (src_len, src_buf);
1577 /* If STMT1 is a mem{,p}cpy call, adjust it and remove
1579 if (lhs1 && DECL_FUNCTION_CODE (callee1) == BUILT_IN_MEMPCPY)
1580 gimple_call_set_lhs (stmt1, NULL_TREE);
1581 gimple_call_set_arg (stmt1, 1, new_str_cst);
1582 gimple_call_set_arg (stmt1, 2,
1583 build_int_cst (TREE_TYPE (len1), src_len));
1584 update_stmt (stmt1);
1585 unlink_stmt_vdef (stmt2);
1586 gsi_remove (gsi_p, true);
1587 release_defs (stmt2);
1588 if (lhs1 && DECL_FUNCTION_CODE (callee1) == BUILT_IN_MEMPCPY)
1589 release_ssa_name (lhs1);
1594 /* Otherwise, if STMT1 is length 1 memcpy optimized into
1595 assignment, remove STMT1 and change memset call into
1597 gimple_stmt_iterator gsi = gsi_for_stmt (stmt1);
1599 if (!is_gimple_val (ptr1))
1600 ptr1 = force_gimple_operand_gsi (gsi_p, ptr1, true, NULL_TREE,
1601 true, GSI_SAME_STMT);
1602 gimple_call_set_fndecl (stmt2, built_in_decls [BUILT_IN_MEMCPY]);
1603 gimple_call_set_arg (stmt2, 0, ptr1);
1604 gimple_call_set_arg (stmt2, 1, new_str_cst);
1605 gimple_call_set_arg (stmt2, 2,
1606 build_int_cst (TREE_TYPE (len2), src_len));
1607 unlink_stmt_vdef (stmt1);
1608 gsi_remove (&gsi, true);
1609 release_defs (stmt1);
1610 update_stmt (stmt2);
1621 /* Run bitwise and assignments throug the folder. If the first argument is an
1622 ssa name that is itself a result of a typecast of an ADDR_EXPR to an
1623 integer, feed the ADDR_EXPR to the folder rather than the ssa name.
1627 simplify_bitwise_and (gimple_stmt_iterator *gsi, gimple stmt)
1630 tree arg1 = gimple_assign_rhs1 (stmt);
1631 tree arg2 = gimple_assign_rhs2 (stmt);
1633 if (TREE_CODE (arg2) != INTEGER_CST)
1636 if (TREE_CODE (arg1) == SSA_NAME && !SSA_NAME_IS_DEFAULT_DEF (arg1))
1638 gimple def = SSA_NAME_DEF_STMT (arg1);
1640 if (gimple_assign_cast_p (def)
1641 && INTEGRAL_TYPE_P (gimple_expr_type (def)))
1643 tree op = gimple_assign_rhs1 (def);
1645 if (TREE_CODE (op) == ADDR_EXPR)
1650 res = fold_binary_loc (gimple_location (stmt),
1651 BIT_AND_EXPR, TREE_TYPE (gimple_assign_lhs (stmt)),
1653 if (res && is_gimple_min_invariant (res))
1655 gimple_assign_set_rhs_from_tree (gsi, res);
1662 /* Perform re-associations of the plus or minus statement STMT that are
1663 always permitted. Returns true if the CFG was changed. */
1666 associate_plusminus (gimple stmt)
1668 tree rhs1 = gimple_assign_rhs1 (stmt);
1669 tree rhs2 = gimple_assign_rhs2 (stmt);
1670 enum tree_code code = gimple_assign_rhs_code (stmt);
1671 gimple_stmt_iterator gsi;
1674 /* We can't reassociate at all for saturating types. */
1675 if (TYPE_SATURATING (TREE_TYPE (rhs1)))
1678 /* First contract negates. */
1683 /* A +- (-B) -> A -+ B. */
1684 if (TREE_CODE (rhs2) == SSA_NAME)
1686 gimple def_stmt = SSA_NAME_DEF_STMT (rhs2);
1687 if (is_gimple_assign (def_stmt)
1688 && gimple_assign_rhs_code (def_stmt) == NEGATE_EXPR
1689 && can_propagate_from (def_stmt))
1691 code = (code == MINUS_EXPR) ? PLUS_EXPR : MINUS_EXPR;
1692 gimple_assign_set_rhs_code (stmt, code);
1693 rhs2 = gimple_assign_rhs1 (def_stmt);
1694 gimple_assign_set_rhs2 (stmt, rhs2);
1695 gimple_set_modified (stmt, true);
1700 /* (-A) + B -> B - A. */
1701 if (TREE_CODE (rhs1) == SSA_NAME
1702 && code == PLUS_EXPR)
1704 gimple def_stmt = SSA_NAME_DEF_STMT (rhs1);
1705 if (is_gimple_assign (def_stmt)
1706 && gimple_assign_rhs_code (def_stmt) == NEGATE_EXPR
1707 && can_propagate_from (def_stmt))
1710 gimple_assign_set_rhs_code (stmt, code);
1712 gimple_assign_set_rhs1 (stmt, rhs1);
1713 rhs2 = gimple_assign_rhs1 (def_stmt);
1714 gimple_assign_set_rhs2 (stmt, rhs2);
1715 gimple_set_modified (stmt, true);
1722 /* We can't reassociate floating-point or fixed-point plus or minus
1723 because of saturation to +-Inf. */
1724 if (FLOAT_TYPE_P (TREE_TYPE (rhs1))
1725 || FIXED_POINT_TYPE_P (TREE_TYPE (rhs1)))
1728 /* Second match patterns that allow contracting a plus-minus pair
1729 irrespective of overflow issues.
1731 (A +- B) - A -> +- B
1733 (CST +- A) +- CST -> CST +- A
1734 (A + CST) +- CST -> A + CST
1737 A - (A +- B) -> -+ B
1738 A +- (B +- A) -> +- B
1739 CST +- (CST +- A) -> CST +- A
1740 CST +- (A +- CST) -> CST +- A
1743 via commutating the addition and contracting operations to zero
1744 by reassociation. */
1746 gsi = gsi_for_stmt (stmt);
1747 if (TREE_CODE (rhs1) == SSA_NAME)
1749 gimple def_stmt = SSA_NAME_DEF_STMT (rhs1);
1750 if (is_gimple_assign (def_stmt) && can_propagate_from (def_stmt))
1752 enum tree_code def_code = gimple_assign_rhs_code (def_stmt);
1753 if (def_code == PLUS_EXPR
1754 || def_code == MINUS_EXPR)
1756 tree def_rhs1 = gimple_assign_rhs1 (def_stmt);
1757 tree def_rhs2 = gimple_assign_rhs2 (def_stmt);
1758 if (operand_equal_p (def_rhs1, rhs2, 0)
1759 && code == MINUS_EXPR)
1761 /* (A +- B) - A -> +- B. */
1762 code = ((def_code == PLUS_EXPR)
1763 ? TREE_CODE (def_rhs2) : NEGATE_EXPR);
1766 gimple_assign_set_rhs_with_ops (&gsi, code, rhs1, NULL_TREE);
1767 gcc_assert (gsi_stmt (gsi) == stmt);
1768 gimple_set_modified (stmt, true);
1770 else if (operand_equal_p (def_rhs2, rhs2, 0)
1771 && code != def_code)
1773 /* (A +- B) -+ B -> A. */
1774 code = TREE_CODE (def_rhs1);
1777 gimple_assign_set_rhs_with_ops (&gsi, code, rhs1, NULL_TREE);
1778 gcc_assert (gsi_stmt (gsi) == stmt);
1779 gimple_set_modified (stmt, true);
1781 else if (TREE_CODE (rhs2) == INTEGER_CST
1782 && TREE_CODE (def_rhs1) == INTEGER_CST)
1784 /* (CST +- A) +- CST -> CST +- A. */
1785 tree cst = fold_binary (code, TREE_TYPE (rhs1),
1787 if (cst && !TREE_OVERFLOW (cst))
1790 gimple_assign_set_rhs_code (stmt, code);
1792 gimple_assign_set_rhs1 (stmt, rhs1);
1794 gimple_assign_set_rhs2 (stmt, rhs2);
1795 gimple_set_modified (stmt, true);
1798 else if (TREE_CODE (rhs2) == INTEGER_CST
1799 && TREE_CODE (def_rhs2) == INTEGER_CST
1800 && def_code == PLUS_EXPR)
1802 /* (A + CST) +- CST -> A + CST. */
1803 tree cst = fold_binary (code, TREE_TYPE (rhs1),
1805 if (cst && !TREE_OVERFLOW (cst))
1808 gimple_assign_set_rhs_code (stmt, code);
1810 gimple_assign_set_rhs1 (stmt, rhs1);
1812 gimple_assign_set_rhs2 (stmt, rhs2);
1813 gimple_set_modified (stmt, true);
1817 else if (def_code == BIT_NOT_EXPR
1818 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
1820 tree def_rhs1 = gimple_assign_rhs1 (def_stmt);
1821 if (code == PLUS_EXPR
1822 && operand_equal_p (def_rhs1, rhs2, 0))
1826 rhs1 = build_int_cst_type (TREE_TYPE (rhs2), -1);
1828 gimple_assign_set_rhs_with_ops (&gsi, code, rhs1, NULL_TREE);
1829 gcc_assert (gsi_stmt (gsi) == stmt);
1830 gimple_set_modified (stmt, true);
1832 else if (code == PLUS_EXPR
1833 && integer_onep (rhs1))
1839 gimple_assign_set_rhs_with_ops (&gsi, code, rhs1, NULL_TREE);
1840 gcc_assert (gsi_stmt (gsi) == stmt);
1841 gimple_set_modified (stmt, true);
1847 if (rhs2 && TREE_CODE (rhs2) == SSA_NAME)
1849 gimple def_stmt = SSA_NAME_DEF_STMT (rhs2);
1850 if (is_gimple_assign (def_stmt) && can_propagate_from (def_stmt))
1852 enum tree_code def_code = gimple_assign_rhs_code (def_stmt);
1853 if (def_code == PLUS_EXPR
1854 || def_code == MINUS_EXPR)
1856 tree def_rhs1 = gimple_assign_rhs1 (def_stmt);
1857 tree def_rhs2 = gimple_assign_rhs2 (def_stmt);
1858 if (operand_equal_p (def_rhs1, rhs1, 0)
1859 && code == MINUS_EXPR)
1861 /* A - (A +- B) -> -+ B. */
1862 code = ((def_code == PLUS_EXPR)
1863 ? NEGATE_EXPR : TREE_CODE (def_rhs2));
1866 gimple_assign_set_rhs_with_ops (&gsi, code, rhs1, NULL_TREE);
1867 gcc_assert (gsi_stmt (gsi) == stmt);
1868 gimple_set_modified (stmt, true);
1870 else if (operand_equal_p (def_rhs2, rhs1, 0)
1871 && code != def_code)
1873 /* A +- (B +- A) -> +- B. */
1874 code = ((code == PLUS_EXPR)
1875 ? TREE_CODE (def_rhs1) : NEGATE_EXPR);
1878 gimple_assign_set_rhs_with_ops (&gsi, code, rhs1, NULL_TREE);
1879 gcc_assert (gsi_stmt (gsi) == stmt);
1880 gimple_set_modified (stmt, true);
1882 else if (TREE_CODE (rhs1) == INTEGER_CST
1883 && TREE_CODE (def_rhs1) == INTEGER_CST)
1885 /* CST +- (CST +- A) -> CST +- A. */
1886 tree cst = fold_binary (code, TREE_TYPE (rhs2),
1888 if (cst && !TREE_OVERFLOW (cst))
1890 code = (code == def_code ? PLUS_EXPR : MINUS_EXPR);
1891 gimple_assign_set_rhs_code (stmt, code);
1893 gimple_assign_set_rhs1 (stmt, rhs1);
1895 gimple_assign_set_rhs2 (stmt, rhs2);
1896 gimple_set_modified (stmt, true);
1899 else if (TREE_CODE (rhs1) == INTEGER_CST
1900 && TREE_CODE (def_rhs2) == INTEGER_CST)
1902 /* CST +- (A +- CST) -> CST +- A. */
1903 tree cst = fold_binary (def_code == code
1904 ? PLUS_EXPR : MINUS_EXPR,
1907 if (cst && !TREE_OVERFLOW (cst))
1910 gimple_assign_set_rhs1 (stmt, rhs1);
1912 gimple_assign_set_rhs2 (stmt, rhs2);
1913 gimple_set_modified (stmt, true);
1917 else if (def_code == BIT_NOT_EXPR
1918 && INTEGRAL_TYPE_P (TREE_TYPE (rhs2)))
1920 tree def_rhs1 = gimple_assign_rhs1 (def_stmt);
1921 if (code == PLUS_EXPR
1922 && operand_equal_p (def_rhs1, rhs1, 0))
1926 rhs1 = build_int_cst_type (TREE_TYPE (rhs1), -1);
1928 gimple_assign_set_rhs_with_ops (&gsi, code, rhs1, NULL_TREE);
1929 gcc_assert (gsi_stmt (gsi) == stmt);
1930 gimple_set_modified (stmt, true);
1937 if (gimple_modified_p (stmt))
1939 fold_stmt_inplace (stmt);
1941 if (maybe_clean_or_replace_eh_stmt (stmt, stmt)
1942 && gimple_purge_dead_eh_edges (gimple_bb (stmt)))
1949 /* Main entry point for the forward propagation optimizer. */
1952 tree_ssa_forward_propagate_single_use_vars (void)
1955 unsigned int todoflags = 0;
1957 cfg_changed = false;
1961 gimple_stmt_iterator gsi;
1963 /* Note we update GSI within the loop as necessary. */
1964 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); )
1966 gimple stmt = gsi_stmt (gsi);
1968 /* If this statement sets an SSA_NAME to an address,
1969 try to propagate the address into the uses of the SSA_NAME. */
1970 if (is_gimple_assign (stmt))
1972 tree lhs = gimple_assign_lhs (stmt);
1973 tree rhs = gimple_assign_rhs1 (stmt);
1975 if (TREE_CODE (lhs) != SSA_NAME)
1981 if (gimple_assign_rhs_code (stmt) == ADDR_EXPR
1982 /* Handle pointer conversions on invariant addresses
1983 as well, as this is valid gimple. */
1984 || (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt))
1985 && TREE_CODE (rhs) == ADDR_EXPR
1986 && POINTER_TYPE_P (TREE_TYPE (lhs))))
1988 tree base = get_base_address (TREE_OPERAND (rhs, 0));
1991 || decl_address_invariant_p (base))
1992 && !stmt_references_abnormal_ssa_name (stmt)
1993 && forward_propagate_addr_expr (lhs, rhs))
1995 release_defs (stmt);
1996 todoflags |= TODO_remove_unused_locals;
1997 gsi_remove (&gsi, true);
2002 else if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR
2003 && can_propagate_from (stmt))
2005 if (TREE_CODE (gimple_assign_rhs2 (stmt)) == INTEGER_CST
2006 /* ??? Better adjust the interface to that function
2007 instead of building new trees here. */
2008 && forward_propagate_addr_expr
2012 fold_build2 (MEM_REF,
2013 TREE_TYPE (TREE_TYPE (rhs)),
2017 gimple_assign_rhs2 (stmt))))))
2019 release_defs (stmt);
2020 todoflags |= TODO_remove_unused_locals;
2021 gsi_remove (&gsi, true);
2023 else if (is_gimple_min_invariant (rhs))
2025 /* Make sure to fold &a[0] + off_1 here. */
2026 fold_stmt_inplace (stmt);
2028 if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR)
2034 else if ((gimple_assign_rhs_code (stmt) == BIT_NOT_EXPR
2035 || gimple_assign_rhs_code (stmt) == NEGATE_EXPR)
2036 && TREE_CODE (rhs) == SSA_NAME)
2038 simplify_not_neg_expr (&gsi);
2041 else if (gimple_assign_rhs_code (stmt) == COND_EXPR)
2043 /* In this case the entire COND_EXPR is in rhs1. */
2045 fold_defer_overflow_warnings ();
2046 did_something = forward_propagate_into_cond (&gsi);
2047 stmt = gsi_stmt (gsi);
2048 if (did_something == 2)
2050 fold_undefer_overflow_warnings (!TREE_NO_WARNING (rhs)
2051 && did_something, stmt, WARN_STRICT_OVERFLOW_CONDITIONAL);
2054 else if (TREE_CODE_CLASS (gimple_assign_rhs_code (stmt))
2057 if (forward_propagate_comparison (stmt))
2061 else if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR)
2063 simplify_bitwise_and (&gsi, stmt);
2066 else if (gimple_assign_rhs_code (stmt) == PLUS_EXPR
2067 || gimple_assign_rhs_code (stmt) == MINUS_EXPR)
2069 cfg_changed |= associate_plusminus (stmt);
2075 else if (gimple_code (stmt) == GIMPLE_SWITCH)
2077 simplify_gimple_switch (stmt);
2080 else if (gimple_code (stmt) == GIMPLE_COND)
2083 fold_defer_overflow_warnings ();
2084 did_something = forward_propagate_into_gimple_cond (stmt);
2085 if (did_something == 2)
2087 fold_undefer_overflow_warnings (did_something, stmt,
2088 WARN_STRICT_OVERFLOW_CONDITIONAL);
2091 else if (is_gimple_call (stmt))
2093 tree callee = gimple_call_fndecl (stmt);
2094 if (callee == NULL_TREE
2095 || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL
2096 || !simplify_builtin_call (&gsi, callee))
2105 todoflags |= TODO_cleanup_cfg;
2111 gate_forwprop (void)
2113 return flag_tree_forwprop;
2116 struct gimple_opt_pass pass_forwprop =
2120 "forwprop", /* name */
2121 gate_forwprop, /* gate */
2122 tree_ssa_forward_propagate_single_use_vars, /* execute */
2125 0, /* static_pass_number */
2126 TV_TREE_FORWPROP, /* tv_id */
2127 PROP_cfg | PROP_ssa, /* properties_required */
2128 0, /* properties_provided */
2129 0, /* properties_destroyed */
2130 0, /* todo_flags_start */
2134 | TODO_verify_ssa /* todo_flags_finish */