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 "gimple-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 bb = gimple_bb (stmt);
319 gsi = gsi_for_stmt (stmt);
321 gsi_remove (&gsi, true);
322 cfg_changed |= gimple_purge_dead_eh_edges (bb);
324 name = (gimple_assign_copy_p (stmt)) ? gimple_assign_rhs1 (stmt) : NULL;
325 } while (name && TREE_CODE (name) == SSA_NAME);
330 /* Return the rhs of a gimple_assign STMT in a form of a single tree,
331 converted to type TYPE.
333 This should disappear, but is needed so we can combine expressions and use
334 the fold() interfaces. Long term, we need to develop folding and combine
335 routines that deal with gimple exclusively . */
338 rhs_to_tree (tree type, gimple stmt)
340 location_t loc = gimple_location (stmt);
341 enum tree_code code = gimple_assign_rhs_code (stmt);
342 if (get_gimple_rhs_class (code) == GIMPLE_TERNARY_RHS)
343 return fold_build3_loc (loc, code, type, gimple_assign_rhs1 (stmt),
344 gimple_assign_rhs2 (stmt),
345 gimple_assign_rhs3 (stmt));
346 else if (get_gimple_rhs_class (code) == GIMPLE_BINARY_RHS)
347 return fold_build2_loc (loc, code, type, gimple_assign_rhs1 (stmt),
348 gimple_assign_rhs2 (stmt));
349 else if (get_gimple_rhs_class (code) == GIMPLE_UNARY_RHS)
350 return build1 (code, type, gimple_assign_rhs1 (stmt));
351 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS)
352 return gimple_assign_rhs1 (stmt);
357 /* Combine OP0 CODE OP1 in the context of a COND_EXPR. Returns
358 the folded result in a form suitable for COND_EXPR_COND or
359 NULL_TREE, if there is no suitable simplified form. If
360 INVARIANT_ONLY is true only gimple_min_invariant results are
361 considered simplified. */
364 combine_cond_expr_cond (location_t loc, enum tree_code code, tree type,
365 tree op0, tree op1, bool invariant_only)
369 gcc_assert (TREE_CODE_CLASS (code) == tcc_comparison);
371 t = fold_binary_loc (loc, code, type, op0, op1);
375 /* Require that we got a boolean type out if we put one in. */
376 gcc_assert (TREE_CODE (TREE_TYPE (t)) == TREE_CODE (type));
378 /* Canonicalize the combined condition for use in a COND_EXPR. */
379 t = canonicalize_cond_expr_cond (t);
381 /* Bail out if we required an invariant but didn't get one. */
382 if (!t || (invariant_only && !is_gimple_min_invariant (t)))
388 /* Combine the comparison OP0 CODE OP1 at LOC with the defining statements
389 of its operand. Return a new comparison tree or NULL_TREE if there
390 were no simplifying combines. */
393 forward_propagate_into_comparison_1 (location_t loc,
394 enum tree_code code, tree type,
397 tree tmp = NULL_TREE;
398 tree rhs0 = NULL_TREE, rhs1 = NULL_TREE;
399 bool single_use0_p = false, single_use1_p = false;
401 /* For comparisons use the first operand, that is likely to
402 simplify comparisons against constants. */
403 if (TREE_CODE (op0) == SSA_NAME)
405 gimple def_stmt = get_prop_source_stmt (op0, false, &single_use0_p);
406 if (def_stmt && can_propagate_from (def_stmt))
408 rhs0 = rhs_to_tree (TREE_TYPE (op1), def_stmt);
409 tmp = combine_cond_expr_cond (loc, code, type,
410 rhs0, op1, !single_use0_p);
416 /* If that wasn't successful, try the second operand. */
417 if (TREE_CODE (op1) == SSA_NAME)
419 gimple def_stmt = get_prop_source_stmt (op1, false, &single_use1_p);
420 if (def_stmt && can_propagate_from (def_stmt))
422 rhs1 = rhs_to_tree (TREE_TYPE (op0), def_stmt);
423 tmp = combine_cond_expr_cond (loc, code, type,
424 op0, rhs1, !single_use1_p);
430 /* If that wasn't successful either, try both operands. */
431 if (rhs0 != NULL_TREE
432 && rhs1 != NULL_TREE)
433 tmp = combine_cond_expr_cond (loc, code, type,
435 !(single_use0_p && single_use1_p));
440 /* Propagate from the ssa name definition statements of the assignment
441 from a comparison at *GSI into the conditional if that simplifies it.
442 Returns 1 if the stmt was modified and 2 if the CFG needs cleanup,
443 otherwise returns 0. */
446 forward_propagate_into_comparison (gimple_stmt_iterator *gsi)
448 gimple stmt = gsi_stmt (*gsi);
450 bool cfg_changed = false;
451 tree rhs1 = gimple_assign_rhs1 (stmt);
452 tree rhs2 = gimple_assign_rhs2 (stmt);
454 /* Combine the comparison with defining statements. */
455 tmp = forward_propagate_into_comparison_1 (gimple_location (stmt),
456 gimple_assign_rhs_code (stmt),
458 (gimple_assign_lhs (stmt)),
462 gimple_assign_set_rhs_from_tree (gsi, tmp);
464 if (TREE_CODE (rhs1) == SSA_NAME)
465 cfg_changed |= remove_prop_source_from_use (rhs1);
466 if (TREE_CODE (rhs2) == SSA_NAME)
467 cfg_changed |= remove_prop_source_from_use (rhs2);
468 return cfg_changed ? 2 : 1;
474 /* Propagate from the ssa name definition statements of COND_EXPR
475 in GIMPLE_COND statement STMT into the conditional if that simplifies it.
476 Returns zero if no statement was changed, one if there were
477 changes and two if cfg_cleanup needs to run.
479 This must be kept in sync with forward_propagate_into_cond. */
482 forward_propagate_into_gimple_cond (gimple stmt)
484 location_t loc = gimple_location (stmt);
486 enum tree_code code = gimple_cond_code (stmt);
487 bool cfg_changed = false;
488 tree rhs1 = gimple_cond_lhs (stmt);
489 tree rhs2 = gimple_cond_rhs (stmt);
491 /* We can do tree combining on SSA_NAME and comparison expressions. */
492 if (TREE_CODE_CLASS (gimple_cond_code (stmt)) != tcc_comparison)
495 tmp = forward_propagate_into_comparison_1 (loc, code,
500 if (dump_file && tmp)
502 fprintf (dump_file, " Replaced '");
503 print_gimple_expr (dump_file, stmt, 0, 0);
504 fprintf (dump_file, "' with '");
505 print_generic_expr (dump_file, tmp, 0);
506 fprintf (dump_file, "'\n");
509 gimple_cond_set_condition_from_tree (stmt, unshare_expr (tmp));
512 if (TREE_CODE (rhs1) == SSA_NAME)
513 cfg_changed |= remove_prop_source_from_use (rhs1);
514 if (TREE_CODE (rhs2) == SSA_NAME)
515 cfg_changed |= remove_prop_source_from_use (rhs2);
516 return (cfg_changed || is_gimple_min_invariant (tmp)) ? 2 : 1;
523 /* Propagate from the ssa name definition statements of COND_EXPR
524 in the rhs of statement STMT into the conditional if that simplifies it.
525 Returns zero if no statement was changed, one if there were
526 changes and two if cfg_cleanup needs to run.
528 This must be kept in sync with forward_propagate_into_gimple_cond. */
531 forward_propagate_into_cond (gimple_stmt_iterator *gsi_p)
533 gimple stmt = gsi_stmt (*gsi_p);
534 location_t loc = gimple_location (stmt);
535 tree tmp = NULL_TREE;
536 tree cond = gimple_assign_rhs1 (stmt);
538 /* We can do tree combining on SSA_NAME and comparison expressions. */
539 if (COMPARISON_CLASS_P (cond))
540 tmp = forward_propagate_into_comparison_1 (loc, TREE_CODE (cond),
542 TREE_OPERAND (cond, 0),
543 TREE_OPERAND (cond, 1));
544 else if (TREE_CODE (cond) == SSA_NAME)
546 tree name = cond, rhs0;
547 gimple def_stmt = get_prop_source_stmt (name, true, NULL);
548 if (!def_stmt || !can_propagate_from (def_stmt))
551 rhs0 = gimple_assign_rhs1 (def_stmt);
552 tmp = combine_cond_expr_cond (loc, NE_EXPR, boolean_type_node, rhs0,
553 build_int_cst (TREE_TYPE (rhs0), 0),
559 if (dump_file && tmp)
561 fprintf (dump_file, " Replaced '");
562 print_generic_expr (dump_file, cond, 0);
563 fprintf (dump_file, "' with '");
564 print_generic_expr (dump_file, tmp, 0);
565 fprintf (dump_file, "'\n");
568 gimple_assign_set_rhs_from_tree (gsi_p, unshare_expr (tmp));
569 stmt = gsi_stmt (*gsi_p);
572 return is_gimple_min_invariant (tmp) ? 2 : 1;
578 /* We've just substituted an ADDR_EXPR into stmt. Update all the
579 relevant data structures to match. */
582 tidy_after_forward_propagate_addr (gimple stmt)
584 /* We may have turned a trapping insn into a non-trapping insn. */
585 if (maybe_clean_or_replace_eh_stmt (stmt, stmt)
586 && gimple_purge_dead_eh_edges (gimple_bb (stmt)))
589 if (TREE_CODE (gimple_assign_rhs1 (stmt)) == ADDR_EXPR)
590 recompute_tree_invariant_for_addr_expr (gimple_assign_rhs1 (stmt));
593 /* DEF_RHS contains the address of the 0th element in an array.
594 USE_STMT uses type of DEF_RHS to compute the address of an
595 arbitrary element within the array. The (variable) byte offset
596 of the element is contained in OFFSET.
598 We walk back through the use-def chains of OFFSET to verify that
599 it is indeed computing the offset of an element within the array
600 and extract the index corresponding to the given byte offset.
602 We then try to fold the entire address expression into a form
605 If we are successful, we replace the right hand side of USE_STMT
606 with the new address computation. */
609 forward_propagate_addr_into_variable_array_index (tree offset,
611 gimple_stmt_iterator *use_stmt_gsi)
614 gimple offset_def, use_stmt = gsi_stmt (*use_stmt_gsi);
617 if (TREE_CODE (TREE_OPERAND (def_rhs, 0)) == ARRAY_REF)
618 tunit = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (def_rhs)));
619 else if (TREE_CODE (TREE_TYPE (TREE_OPERAND (def_rhs, 0))) == ARRAY_TYPE)
620 tunit = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (TREE_TYPE (def_rhs))));
623 if (!host_integerp (tunit, 1))
626 /* Get the offset's defining statement. */
627 offset_def = SSA_NAME_DEF_STMT (offset);
629 /* Try to find an expression for a proper index. This is either a
630 multiplication expression by the element size or just the ssa name we came
631 along in case the element size is one. In that case, however, we do not
632 allow multiplications because they can be computing index to a higher
633 level dimension (PR 37861). */
634 if (integer_onep (tunit))
636 if (is_gimple_assign (offset_def)
637 && gimple_assign_rhs_code (offset_def) == MULT_EXPR)
644 /* The statement which defines OFFSET before type conversion
645 must be a simple GIMPLE_ASSIGN. */
646 if (!is_gimple_assign (offset_def))
649 /* The RHS of the statement which defines OFFSET must be a
650 multiplication of an object by the size of the array elements.
651 This implicitly verifies that the size of the array elements
653 if (gimple_assign_rhs_code (offset_def) == MULT_EXPR
654 && TREE_CODE (gimple_assign_rhs2 (offset_def)) == INTEGER_CST
655 && tree_int_cst_equal (gimple_assign_rhs2 (offset_def), tunit))
657 /* The first operand to the MULT_EXPR is the desired index. */
658 index = gimple_assign_rhs1 (offset_def);
660 /* If we have idx * tunit + CST * tunit re-associate that. */
661 else if ((gimple_assign_rhs_code (offset_def) == PLUS_EXPR
662 || gimple_assign_rhs_code (offset_def) == MINUS_EXPR)
663 && TREE_CODE (gimple_assign_rhs1 (offset_def)) == SSA_NAME
664 && TREE_CODE (gimple_assign_rhs2 (offset_def)) == INTEGER_CST
665 && (tmp = div_if_zero_remainder (EXACT_DIV_EXPR,
666 gimple_assign_rhs2 (offset_def),
667 tunit)) != NULL_TREE)
669 gimple offset_def2 = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (offset_def));
670 if (is_gimple_assign (offset_def2)
671 && gimple_assign_rhs_code (offset_def2) == MULT_EXPR
672 && TREE_CODE (gimple_assign_rhs2 (offset_def2)) == INTEGER_CST
673 && tree_int_cst_equal (gimple_assign_rhs2 (offset_def2), tunit))
675 index = fold_build2 (gimple_assign_rhs_code (offset_def),
677 gimple_assign_rhs1 (offset_def2), tmp);
686 /* Replace the pointer addition with array indexing. */
687 index = force_gimple_operand_gsi (use_stmt_gsi, index, true, NULL_TREE,
688 true, GSI_SAME_STMT);
689 if (TREE_CODE (TREE_OPERAND (def_rhs, 0)) == ARRAY_REF)
691 new_rhs = unshare_expr (def_rhs);
692 TREE_OPERAND (TREE_OPERAND (new_rhs, 0), 1) = index;
696 new_rhs = build4 (ARRAY_REF, TREE_TYPE (TREE_TYPE (TREE_TYPE (def_rhs))),
697 unshare_expr (TREE_OPERAND (def_rhs, 0)),
698 index, integer_zero_node, NULL_TREE);
699 new_rhs = build_fold_addr_expr (new_rhs);
700 if (!useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (use_stmt)),
701 TREE_TYPE (new_rhs)))
703 new_rhs = force_gimple_operand_gsi (use_stmt_gsi, new_rhs, true,
704 NULL_TREE, true, GSI_SAME_STMT);
705 new_rhs = fold_convert (TREE_TYPE (gimple_assign_lhs (use_stmt)),
709 gimple_assign_set_rhs_from_tree (use_stmt_gsi, new_rhs);
710 use_stmt = gsi_stmt (*use_stmt_gsi);
712 /* That should have created gimple, so there is no need to
713 record information to undo the propagation. */
714 fold_stmt_inplace (use_stmt);
715 tidy_after_forward_propagate_addr (use_stmt);
719 /* NAME is a SSA_NAME representing DEF_RHS which is of the form
720 ADDR_EXPR <whatever>.
722 Try to forward propagate the ADDR_EXPR into the use USE_STMT.
723 Often this will allow for removal of an ADDR_EXPR and INDIRECT_REF
724 node or for recovery of array indexing from pointer arithmetic.
726 Return true if the propagation was successful (the propagation can
727 be not totally successful, yet things may have been changed). */
730 forward_propagate_addr_expr_1 (tree name, tree def_rhs,
731 gimple_stmt_iterator *use_stmt_gsi,
734 tree lhs, rhs, rhs2, array_ref;
735 gimple use_stmt = gsi_stmt (*use_stmt_gsi);
736 enum tree_code rhs_code;
739 gcc_assert (TREE_CODE (def_rhs) == ADDR_EXPR);
741 lhs = gimple_assign_lhs (use_stmt);
742 rhs_code = gimple_assign_rhs_code (use_stmt);
743 rhs = gimple_assign_rhs1 (use_stmt);
745 /* Trivial cases. The use statement could be a trivial copy or a
746 useless conversion. Recurse to the uses of the lhs as copyprop does
747 not copy through different variant pointers and FRE does not catch
748 all useless conversions. Treat the case of a single-use name and
749 a conversion to def_rhs type separate, though. */
750 if (TREE_CODE (lhs) == SSA_NAME
751 && ((rhs_code == SSA_NAME && rhs == name)
752 || CONVERT_EXPR_CODE_P (rhs_code)))
754 /* Only recurse if we don't deal with a single use or we cannot
755 do the propagation to the current statement. In particular
756 we can end up with a conversion needed for a non-invariant
757 address which we cannot do in a single statement. */
759 || (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (def_rhs))
760 && (!is_gimple_min_invariant (def_rhs)
761 || (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
762 && POINTER_TYPE_P (TREE_TYPE (def_rhs))
763 && (TYPE_PRECISION (TREE_TYPE (lhs))
764 > TYPE_PRECISION (TREE_TYPE (def_rhs)))))))
765 return forward_propagate_addr_expr (lhs, def_rhs);
767 gimple_assign_set_rhs1 (use_stmt, unshare_expr (def_rhs));
768 if (useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (def_rhs)))
769 gimple_assign_set_rhs_code (use_stmt, TREE_CODE (def_rhs));
771 gimple_assign_set_rhs_code (use_stmt, NOP_EXPR);
775 /* Propagate through constant pointer adjustments. */
776 if (TREE_CODE (lhs) == SSA_NAME
777 && rhs_code == POINTER_PLUS_EXPR
779 && TREE_CODE (gimple_assign_rhs2 (use_stmt)) == INTEGER_CST)
782 /* As we come here with non-invariant addresses in def_rhs we need
783 to make sure we can build a valid constant offsetted address
784 for further propagation. Simply rely on fold building that
785 and check after the fact. */
786 new_def_rhs = fold_build2 (MEM_REF, TREE_TYPE (TREE_TYPE (rhs)),
788 fold_convert (ptr_type_node,
789 gimple_assign_rhs2 (use_stmt)));
790 if (TREE_CODE (new_def_rhs) == MEM_REF
791 && !is_gimple_mem_ref_addr (TREE_OPERAND (new_def_rhs, 0)))
793 new_def_rhs = build_fold_addr_expr_with_type (new_def_rhs,
796 /* Recurse. If we could propagate into all uses of lhs do not
797 bother to replace into the current use but just pretend we did. */
798 if (TREE_CODE (new_def_rhs) == ADDR_EXPR
799 && forward_propagate_addr_expr (lhs, new_def_rhs))
802 if (useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (new_def_rhs)))
803 gimple_assign_set_rhs_with_ops (use_stmt_gsi, TREE_CODE (new_def_rhs),
804 new_def_rhs, NULL_TREE);
805 else if (is_gimple_min_invariant (new_def_rhs))
806 gimple_assign_set_rhs_with_ops (use_stmt_gsi, NOP_EXPR,
807 new_def_rhs, NULL_TREE);
810 gcc_assert (gsi_stmt (*use_stmt_gsi) == use_stmt);
811 update_stmt (use_stmt);
815 /* Now strip away any outer COMPONENT_REF/ARRAY_REF nodes from the LHS.
816 ADDR_EXPR will not appear on the LHS. */
817 lhs = gimple_assign_lhs (use_stmt);
818 while (handled_component_p (lhs))
819 lhs = TREE_OPERAND (lhs, 0);
821 /* Now see if the LHS node is a MEM_REF using NAME. If so,
822 propagate the ADDR_EXPR into the use of NAME and fold the result. */
823 if (TREE_CODE (lhs) == MEM_REF
824 && TREE_OPERAND (lhs, 0) == name)
827 HOST_WIDE_INT def_rhs_offset;
828 /* If the address is invariant we can always fold it. */
829 if ((def_rhs_base = get_addr_base_and_unit_offset (TREE_OPERAND (def_rhs, 0),
832 double_int off = mem_ref_offset (lhs);
834 off = double_int_add (off,
835 shwi_to_double_int (def_rhs_offset));
836 if (TREE_CODE (def_rhs_base) == MEM_REF)
838 off = double_int_add (off, mem_ref_offset (def_rhs_base));
839 new_ptr = TREE_OPERAND (def_rhs_base, 0);
842 new_ptr = build_fold_addr_expr (def_rhs_base);
843 TREE_OPERAND (lhs, 0) = new_ptr;
844 TREE_OPERAND (lhs, 1)
845 = double_int_to_tree (TREE_TYPE (TREE_OPERAND (lhs, 1)), off);
846 tidy_after_forward_propagate_addr (use_stmt);
847 /* Continue propagating into the RHS if this was not the only use. */
851 /* If the LHS is a plain dereference and the value type is the same as
852 that of the pointed-to type of the address we can put the
853 dereferenced address on the LHS preserving the original alias-type. */
854 else if (gimple_assign_lhs (use_stmt) == lhs
855 && useless_type_conversion_p
856 (TREE_TYPE (TREE_OPERAND (def_rhs, 0)),
857 TREE_TYPE (gimple_assign_rhs1 (use_stmt))))
859 tree *def_rhs_basep = &TREE_OPERAND (def_rhs, 0);
860 tree new_offset, new_base, saved;
861 while (handled_component_p (*def_rhs_basep))
862 def_rhs_basep = &TREE_OPERAND (*def_rhs_basep, 0);
863 saved = *def_rhs_basep;
864 if (TREE_CODE (*def_rhs_basep) == MEM_REF)
866 new_base = TREE_OPERAND (*def_rhs_basep, 0);
868 = int_const_binop (PLUS_EXPR, TREE_OPERAND (lhs, 1),
869 TREE_OPERAND (*def_rhs_basep, 1));
873 new_base = build_fold_addr_expr (*def_rhs_basep);
874 new_offset = TREE_OPERAND (lhs, 1);
876 *def_rhs_basep = build2 (MEM_REF, TREE_TYPE (*def_rhs_basep),
877 new_base, new_offset);
878 gimple_assign_set_lhs (use_stmt,
879 unshare_expr (TREE_OPERAND (def_rhs, 0)));
880 *def_rhs_basep = saved;
881 tidy_after_forward_propagate_addr (use_stmt);
882 /* Continue propagating into the RHS if this was not the
888 /* We can have a struct assignment dereferencing our name twice.
889 Note that we didn't propagate into the lhs to not falsely
890 claim we did when propagating into the rhs. */
894 /* Strip away any outer COMPONENT_REF, ARRAY_REF or ADDR_EXPR
895 nodes from the RHS. */
896 rhs = gimple_assign_rhs1 (use_stmt);
897 if (TREE_CODE (rhs) == ADDR_EXPR)
898 rhs = TREE_OPERAND (rhs, 0);
899 while (handled_component_p (rhs))
900 rhs = TREE_OPERAND (rhs, 0);
902 /* Now see if the RHS node is a MEM_REF using NAME. If so,
903 propagate the ADDR_EXPR into the use of NAME and fold the result. */
904 if (TREE_CODE (rhs) == MEM_REF
905 && TREE_OPERAND (rhs, 0) == name)
908 HOST_WIDE_INT def_rhs_offset;
909 if ((def_rhs_base = get_addr_base_and_unit_offset (TREE_OPERAND (def_rhs, 0),
912 double_int off = mem_ref_offset (rhs);
914 off = double_int_add (off,
915 shwi_to_double_int (def_rhs_offset));
916 if (TREE_CODE (def_rhs_base) == MEM_REF)
918 off = double_int_add (off, mem_ref_offset (def_rhs_base));
919 new_ptr = TREE_OPERAND (def_rhs_base, 0);
922 new_ptr = build_fold_addr_expr (def_rhs_base);
923 TREE_OPERAND (rhs, 0) = new_ptr;
924 TREE_OPERAND (rhs, 1)
925 = double_int_to_tree (TREE_TYPE (TREE_OPERAND (rhs, 1)), off);
926 fold_stmt_inplace (use_stmt);
927 tidy_after_forward_propagate_addr (use_stmt);
930 /* If the LHS is a plain dereference and the value type is the same as
931 that of the pointed-to type of the address we can put the
932 dereferenced address on the LHS preserving the original alias-type. */
933 else if (gimple_assign_rhs1 (use_stmt) == rhs
934 && useless_type_conversion_p
935 (TREE_TYPE (gimple_assign_lhs (use_stmt)),
936 TREE_TYPE (TREE_OPERAND (def_rhs, 0))))
938 tree *def_rhs_basep = &TREE_OPERAND (def_rhs, 0);
939 tree new_offset, new_base, saved;
940 while (handled_component_p (*def_rhs_basep))
941 def_rhs_basep = &TREE_OPERAND (*def_rhs_basep, 0);
942 saved = *def_rhs_basep;
943 if (TREE_CODE (*def_rhs_basep) == MEM_REF)
945 new_base = TREE_OPERAND (*def_rhs_basep, 0);
947 = int_const_binop (PLUS_EXPR, TREE_OPERAND (rhs, 1),
948 TREE_OPERAND (*def_rhs_basep, 1));
952 new_base = build_fold_addr_expr (*def_rhs_basep);
953 new_offset = TREE_OPERAND (rhs, 1);
955 *def_rhs_basep = build2 (MEM_REF, TREE_TYPE (*def_rhs_basep),
956 new_base, new_offset);
957 gimple_assign_set_rhs1 (use_stmt,
958 unshare_expr (TREE_OPERAND (def_rhs, 0)));
959 *def_rhs_basep = saved;
960 fold_stmt_inplace (use_stmt);
961 tidy_after_forward_propagate_addr (use_stmt);
966 /* If the use of the ADDR_EXPR is not a POINTER_PLUS_EXPR, there
968 if (gimple_assign_rhs_code (use_stmt) != POINTER_PLUS_EXPR
969 || gimple_assign_rhs1 (use_stmt) != name)
972 /* The remaining cases are all for turning pointer arithmetic into
973 array indexing. They only apply when we have the address of
974 element zero in an array. If that is not the case then there
976 array_ref = TREE_OPERAND (def_rhs, 0);
977 if ((TREE_CODE (array_ref) != ARRAY_REF
978 || TREE_CODE (TREE_TYPE (TREE_OPERAND (array_ref, 0))) != ARRAY_TYPE
979 || TREE_CODE (TREE_OPERAND (array_ref, 1)) != INTEGER_CST)
980 && TREE_CODE (TREE_TYPE (array_ref)) != ARRAY_TYPE)
983 rhs2 = gimple_assign_rhs2 (use_stmt);
984 /* Try to optimize &x[C1] p+ C2 where C2 is a multiple of the size
985 of the elements in X into &x[C1 + C2/element size]. */
986 if (TREE_CODE (rhs2) == INTEGER_CST)
988 tree new_rhs = maybe_fold_stmt_addition (gimple_location (use_stmt),
993 tree type = TREE_TYPE (gimple_assign_lhs (use_stmt));
994 new_rhs = unshare_expr (new_rhs);
995 if (!useless_type_conversion_p (type, TREE_TYPE (new_rhs)))
997 if (!is_gimple_min_invariant (new_rhs))
998 new_rhs = force_gimple_operand_gsi (use_stmt_gsi, new_rhs,
1000 true, GSI_SAME_STMT);
1001 new_rhs = fold_convert (type, new_rhs);
1003 gimple_assign_set_rhs_from_tree (use_stmt_gsi, new_rhs);
1004 use_stmt = gsi_stmt (*use_stmt_gsi);
1005 update_stmt (use_stmt);
1006 tidy_after_forward_propagate_addr (use_stmt);
1011 /* Try to optimize &x[0] p+ OFFSET where OFFSET is defined by
1012 converting a multiplication of an index by the size of the
1013 array elements, then the result is converted into the proper
1014 type for the arithmetic. */
1015 if (TREE_CODE (rhs2) == SSA_NAME
1016 && (TREE_CODE (array_ref) != ARRAY_REF
1017 || integer_zerop (TREE_OPERAND (array_ref, 1)))
1018 && useless_type_conversion_p (TREE_TYPE (name), TREE_TYPE (def_rhs))
1019 /* Avoid problems with IVopts creating PLUS_EXPRs with a
1020 different type than their operands. */
1021 && useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (def_rhs)))
1022 return forward_propagate_addr_into_variable_array_index (rhs2, def_rhs,
1027 /* STMT is a statement of the form SSA_NAME = ADDR_EXPR <whatever>.
1029 Try to forward propagate the ADDR_EXPR into all uses of the SSA_NAME.
1030 Often this will allow for removal of an ADDR_EXPR and INDIRECT_REF
1031 node or for recovery of array indexing from pointer arithmetic.
1032 Returns true, if all uses have been propagated into. */
1035 forward_propagate_addr_expr (tree name, tree rhs)
1037 int stmt_loop_depth = gimple_bb (SSA_NAME_DEF_STMT (name))->loop_depth;
1038 imm_use_iterator iter;
1041 bool single_use_p = has_single_use (name);
1043 FOR_EACH_IMM_USE_STMT (use_stmt, iter, name)
1048 /* If the use is not in a simple assignment statement, then
1049 there is nothing we can do. */
1050 if (gimple_code (use_stmt) != GIMPLE_ASSIGN)
1052 if (!is_gimple_debug (use_stmt))
1057 /* If the use is in a deeper loop nest, then we do not want
1058 to propagate non-invariant ADDR_EXPRs into the loop as that
1059 is likely adding expression evaluations into the loop. */
1060 if (gimple_bb (use_stmt)->loop_depth > stmt_loop_depth
1061 && !is_gimple_min_invariant (rhs))
1068 gimple_stmt_iterator gsi = gsi_for_stmt (use_stmt);
1069 result = forward_propagate_addr_expr_1 (name, rhs, &gsi,
1071 /* If the use has moved to a different statement adjust
1072 the update machinery for the old statement too. */
1073 if (use_stmt != gsi_stmt (gsi))
1075 update_stmt (use_stmt);
1076 use_stmt = gsi_stmt (gsi);
1079 update_stmt (use_stmt);
1083 /* Remove intermediate now unused copy and conversion chains. */
1084 use_rhs = gimple_assign_rhs1 (use_stmt);
1086 && TREE_CODE (gimple_assign_lhs (use_stmt)) == SSA_NAME
1087 && TREE_CODE (use_rhs) == SSA_NAME
1088 && has_zero_uses (gimple_assign_lhs (use_stmt)))
1090 gimple_stmt_iterator gsi = gsi_for_stmt (use_stmt);
1091 release_defs (use_stmt);
1092 gsi_remove (&gsi, true);
1096 return all && has_zero_uses (name);
1100 /* Forward propagate the comparison defined in STMT like
1101 cond_1 = x CMP y to uses of the form
1105 Returns true if stmt is now unused. */
1108 forward_propagate_comparison (gimple stmt)
1110 tree name = gimple_assign_lhs (stmt);
1112 tree tmp = NULL_TREE;
1113 gimple_stmt_iterator gsi;
1114 enum tree_code code;
1117 /* Don't propagate ssa names that occur in abnormal phis. */
1118 if ((TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
1119 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_assign_rhs1 (stmt)))
1120 || (TREE_CODE (gimple_assign_rhs2 (stmt)) == SSA_NAME
1121 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_assign_rhs2 (stmt))))
1124 /* Do not un-cse comparisons. But propagate through copies. */
1125 use_stmt = get_prop_dest_stmt (name, &name);
1127 || !is_gimple_assign (use_stmt))
1130 code = gimple_assign_rhs_code (use_stmt);
1131 lhs = gimple_assign_lhs (use_stmt);
1132 if (!INTEGRAL_TYPE_P (TREE_TYPE (lhs)))
1135 /* We can propagate the condition into a conversion. */
1136 if (CONVERT_EXPR_CODE_P (code))
1138 /* Avoid using fold here as that may create a COND_EXPR with
1139 non-boolean condition as canonical form. */
1140 tmp = build2 (gimple_assign_rhs_code (stmt), TREE_TYPE (lhs),
1141 gimple_assign_rhs1 (stmt), gimple_assign_rhs2 (stmt));
1143 /* We can propagate the condition into a statement that
1144 computes the logical negation of the comparison result. */
1145 else if ((code == BIT_NOT_EXPR
1146 && TYPE_PRECISION (TREE_TYPE (lhs)) == 1)
1147 || (code == BIT_XOR_EXPR
1148 && integer_onep (gimple_assign_rhs2 (use_stmt))))
1150 tree type = TREE_TYPE (gimple_assign_rhs1 (stmt));
1151 bool nans = HONOR_NANS (TYPE_MODE (type));
1152 enum tree_code inv_code;
1153 inv_code = invert_tree_comparison (gimple_assign_rhs_code (stmt), nans);
1154 if (inv_code == ERROR_MARK)
1157 tmp = build2 (inv_code, TREE_TYPE (lhs), gimple_assign_rhs1 (stmt),
1158 gimple_assign_rhs2 (stmt));
1163 gsi = gsi_for_stmt (use_stmt);
1164 gimple_assign_set_rhs_from_tree (&gsi, unshare_expr (tmp));
1165 use_stmt = gsi_stmt (gsi);
1166 update_stmt (use_stmt);
1168 if (dump_file && (dump_flags & TDF_DETAILS))
1170 fprintf (dump_file, " Replaced '");
1171 print_gimple_expr (dump_file, stmt, 0, dump_flags);
1172 fprintf (dump_file, "' with '");
1173 print_gimple_expr (dump_file, use_stmt, 0, dump_flags);
1174 fprintf (dump_file, "'\n");
1177 /* Remove defining statements. */
1178 return remove_prop_source_from_use (name);
1182 /* If we have lhs = ~x (STMT), look and see if earlier we had x = ~y.
1183 If so, we can change STMT into lhs = y which can later be copy
1184 propagated. Similarly for negation.
1186 This could trivially be formulated as a forward propagation
1187 to immediate uses. However, we already had an implementation
1188 from DOM which used backward propagation via the use-def links.
1190 It turns out that backward propagation is actually faster as
1191 there's less work to do for each NOT/NEG expression we find.
1192 Backwards propagation needs to look at the statement in a single
1193 backlink. Forward propagation needs to look at potentially more
1194 than one forward link.
1196 Returns true when the statement was changed. */
1199 simplify_not_neg_expr (gimple_stmt_iterator *gsi_p)
1201 gimple stmt = gsi_stmt (*gsi_p);
1202 tree rhs = gimple_assign_rhs1 (stmt);
1203 gimple rhs_def_stmt = SSA_NAME_DEF_STMT (rhs);
1205 /* See if the RHS_DEF_STMT has the same form as our statement. */
1206 if (is_gimple_assign (rhs_def_stmt)
1207 && gimple_assign_rhs_code (rhs_def_stmt) == gimple_assign_rhs_code (stmt))
1209 tree rhs_def_operand = gimple_assign_rhs1 (rhs_def_stmt);
1211 /* Verify that RHS_DEF_OPERAND is a suitable SSA_NAME. */
1212 if (TREE_CODE (rhs_def_operand) == SSA_NAME
1213 && ! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs_def_operand))
1215 gimple_assign_set_rhs_from_tree (gsi_p, rhs_def_operand);
1216 stmt = gsi_stmt (*gsi_p);
1225 /* STMT is a SWITCH_EXPR for which we attempt to find equivalent forms of
1226 the condition which we may be able to optimize better. */
1229 simplify_gimple_switch (gimple stmt)
1231 tree cond = gimple_switch_index (stmt);
1235 /* The optimization that we really care about is removing unnecessary
1236 casts. That will let us do much better in propagating the inferred
1237 constant at the switch target. */
1238 if (TREE_CODE (cond) == SSA_NAME)
1240 def_stmt = SSA_NAME_DEF_STMT (cond);
1241 if (is_gimple_assign (def_stmt))
1243 if (gimple_assign_rhs_code (def_stmt) == NOP_EXPR)
1248 def = gimple_assign_rhs1 (def_stmt);
1250 /* ??? Why was Jeff testing this? We are gimple... */
1251 gcc_checking_assert (is_gimple_val (def));
1253 to = TREE_TYPE (cond);
1254 ti = TREE_TYPE (def);
1256 /* If we have an extension that preserves value, then we
1257 can copy the source value into the switch. */
1259 need_precision = TYPE_PRECISION (ti);
1261 if (! INTEGRAL_TYPE_P (ti))
1263 else if (TYPE_UNSIGNED (to) && !TYPE_UNSIGNED (ti))
1265 else if (!TYPE_UNSIGNED (to) && TYPE_UNSIGNED (ti))
1266 need_precision += 1;
1267 if (TYPE_PRECISION (to) < need_precision)
1272 gimple_switch_set_index (stmt, def);
1283 /* For pointers p2 and p1 return p2 - p1 if the
1284 difference is known and constant, otherwise return NULL. */
1287 constant_pointer_difference (tree p1, tree p2)
1290 #define CPD_ITERATIONS 5
1291 tree exps[2][CPD_ITERATIONS];
1292 tree offs[2][CPD_ITERATIONS];
1295 for (i = 0; i < 2; i++)
1297 tree p = i ? p1 : p2;
1298 tree off = size_zero_node;
1300 enum tree_code code;
1302 /* For each of p1 and p2 we need to iterate at least
1303 twice, to handle ADDR_EXPR directly in p1/p2,
1304 SSA_NAME with ADDR_EXPR or POINTER_PLUS_EXPR etc.
1305 on definition's stmt RHS. Iterate a few extra times. */
1309 if (!POINTER_TYPE_P (TREE_TYPE (p)))
1311 if (TREE_CODE (p) == ADDR_EXPR)
1313 tree q = TREE_OPERAND (p, 0);
1314 HOST_WIDE_INT offset;
1315 tree base = get_addr_base_and_unit_offset (q, &offset);
1320 off = size_binop (PLUS_EXPR, off, size_int (offset));
1322 if (TREE_CODE (q) == MEM_REF
1323 && TREE_CODE (TREE_OPERAND (q, 0)) == SSA_NAME)
1325 p = TREE_OPERAND (q, 0);
1326 off = size_binop (PLUS_EXPR, off,
1327 double_int_to_tree (sizetype,
1328 mem_ref_offset (q)));
1337 if (TREE_CODE (p) != SSA_NAME)
1341 if (j == CPD_ITERATIONS)
1343 stmt = SSA_NAME_DEF_STMT (p);
1344 if (!is_gimple_assign (stmt) || gimple_assign_lhs (stmt) != p)
1346 code = gimple_assign_rhs_code (stmt);
1347 if (code == POINTER_PLUS_EXPR)
1349 if (TREE_CODE (gimple_assign_rhs2 (stmt)) != INTEGER_CST)
1351 off = size_binop (PLUS_EXPR, off, gimple_assign_rhs2 (stmt));
1352 p = gimple_assign_rhs1 (stmt);
1354 else if (code == ADDR_EXPR || code == NOP_EXPR)
1355 p = gimple_assign_rhs1 (stmt);
1363 for (i = 0; i < cnt[0]; i++)
1364 for (j = 0; j < cnt[1]; j++)
1365 if (exps[0][i] == exps[1][j])
1366 return size_binop (MINUS_EXPR, offs[0][i], offs[1][j]);
1371 /* *GSI_P is a GIMPLE_CALL to a builtin function.
1373 memcpy (p, "abcd", 4);
1374 memset (p + 4, ' ', 3);
1376 memcpy (p, "abcd ", 7);
1377 call if the latter can be stored by pieces during expansion. */
1380 simplify_builtin_call (gimple_stmt_iterator *gsi_p, tree callee2)
1382 gimple stmt1, stmt2 = gsi_stmt (*gsi_p);
1383 tree vuse = gimple_vuse (stmt2);
1386 stmt1 = SSA_NAME_DEF_STMT (vuse);
1388 switch (DECL_FUNCTION_CODE (callee2))
1390 case BUILT_IN_MEMSET:
1391 if (gimple_call_num_args (stmt2) != 3
1392 || gimple_call_lhs (stmt2)
1394 || BITS_PER_UNIT != 8)
1399 tree ptr1, src1, str1, off1, len1, lhs1;
1400 tree ptr2 = gimple_call_arg (stmt2, 0);
1401 tree val2 = gimple_call_arg (stmt2, 1);
1402 tree len2 = gimple_call_arg (stmt2, 2);
1403 tree diff, vdef, new_str_cst;
1405 unsigned int ptr1_align;
1406 unsigned HOST_WIDE_INT src_len;
1408 use_operand_p use_p;
1410 if (!host_integerp (val2, 0)
1411 || !host_integerp (len2, 1))
1413 if (is_gimple_call (stmt1))
1415 /* If first stmt is a call, it needs to be memcpy
1416 or mempcpy, with string literal as second argument and
1418 callee1 = gimple_call_fndecl (stmt1);
1419 if (callee1 == NULL_TREE
1420 || DECL_BUILT_IN_CLASS (callee1) != BUILT_IN_NORMAL
1421 || gimple_call_num_args (stmt1) != 3)
1423 if (DECL_FUNCTION_CODE (callee1) != BUILT_IN_MEMCPY
1424 && DECL_FUNCTION_CODE (callee1) != BUILT_IN_MEMPCPY)
1426 ptr1 = gimple_call_arg (stmt1, 0);
1427 src1 = gimple_call_arg (stmt1, 1);
1428 len1 = gimple_call_arg (stmt1, 2);
1429 lhs1 = gimple_call_lhs (stmt1);
1430 if (!host_integerp (len1, 1))
1432 str1 = string_constant (src1, &off1);
1433 if (str1 == NULL_TREE)
1435 if (!host_integerp (off1, 1)
1436 || compare_tree_int (off1, TREE_STRING_LENGTH (str1) - 1) > 0
1437 || compare_tree_int (len1, TREE_STRING_LENGTH (str1)
1438 - tree_low_cst (off1, 1)) > 0
1439 || TREE_CODE (TREE_TYPE (str1)) != ARRAY_TYPE
1440 || TYPE_MODE (TREE_TYPE (TREE_TYPE (str1)))
1441 != TYPE_MODE (char_type_node))
1444 else if (gimple_assign_single_p (stmt1))
1446 /* Otherwise look for length 1 memcpy optimized into
1448 ptr1 = gimple_assign_lhs (stmt1);
1449 src1 = gimple_assign_rhs1 (stmt1);
1450 if (TREE_CODE (ptr1) != MEM_REF
1451 || TYPE_MODE (TREE_TYPE (ptr1)) != TYPE_MODE (char_type_node)
1452 || !host_integerp (src1, 0))
1454 ptr1 = build_fold_addr_expr (ptr1);
1455 callee1 = NULL_TREE;
1456 len1 = size_one_node;
1458 off1 = size_zero_node;
1464 diff = constant_pointer_difference (ptr1, ptr2);
1465 if (diff == NULL && lhs1 != NULL)
1467 diff = constant_pointer_difference (lhs1, ptr2);
1468 if (DECL_FUNCTION_CODE (callee1) == BUILT_IN_MEMPCPY
1470 diff = size_binop (PLUS_EXPR, diff,
1471 fold_convert (sizetype, len1));
1473 /* If the difference between the second and first destination pointer
1474 is not constant, or is bigger than memcpy length, bail out. */
1476 || !host_integerp (diff, 1)
1477 || tree_int_cst_lt (len1, diff))
1480 /* Use maximum of difference plus memset length and memcpy length
1481 as the new memcpy length, if it is too big, bail out. */
1482 src_len = tree_low_cst (diff, 1);
1483 src_len += tree_low_cst (len2, 1);
1484 if (src_len < (unsigned HOST_WIDE_INT) tree_low_cst (len1, 1))
1485 src_len = tree_low_cst (len1, 1);
1489 /* If mempcpy value is used elsewhere, bail out, as mempcpy
1490 with bigger length will return different result. */
1491 if (lhs1 != NULL_TREE
1492 && DECL_FUNCTION_CODE (callee1) == BUILT_IN_MEMPCPY
1493 && (TREE_CODE (lhs1) != SSA_NAME
1494 || !single_imm_use (lhs1, &use_p, &use_stmt)
1495 || use_stmt != stmt2))
1498 /* If anything reads memory in between memcpy and memset
1499 call, the modified memcpy call might change it. */
1500 vdef = gimple_vdef (stmt1);
1502 && (!single_imm_use (vdef, &use_p, &use_stmt)
1503 || use_stmt != stmt2))
1506 ptr1_align = get_pointer_alignment (ptr1, BIGGEST_ALIGNMENT);
1507 /* Construct the new source string literal. */
1508 src_buf = XALLOCAVEC (char, src_len + 1);
1511 TREE_STRING_POINTER (str1) + tree_low_cst (off1, 1),
1512 tree_low_cst (len1, 1));
1514 src_buf[0] = tree_low_cst (src1, 0);
1515 memset (src_buf + tree_low_cst (diff, 1),
1516 tree_low_cst (val2, 1), tree_low_cst (len2, 1));
1517 src_buf[src_len] = '\0';
1518 /* Neither builtin_strncpy_read_str nor builtin_memcpy_read_str
1519 handle embedded '\0's. */
1520 if (strlen (src_buf) != src_len)
1522 rtl_profile_for_bb (gimple_bb (stmt2));
1523 /* If the new memcpy wouldn't be emitted by storing the literal
1524 by pieces, this optimization might enlarge .rodata too much,
1525 as commonly used string literals couldn't be shared any
1527 if (!can_store_by_pieces (src_len,
1528 builtin_strncpy_read_str,
1529 src_buf, ptr1_align, false))
1532 new_str_cst = build_string_literal (src_len, src_buf);
1535 /* If STMT1 is a mem{,p}cpy call, adjust it and remove
1537 if (lhs1 && DECL_FUNCTION_CODE (callee1) == BUILT_IN_MEMPCPY)
1538 gimple_call_set_lhs (stmt1, NULL_TREE);
1539 gimple_call_set_arg (stmt1, 1, new_str_cst);
1540 gimple_call_set_arg (stmt1, 2,
1541 build_int_cst (TREE_TYPE (len1), src_len));
1542 update_stmt (stmt1);
1543 unlink_stmt_vdef (stmt2);
1544 gsi_remove (gsi_p, true);
1545 release_defs (stmt2);
1546 if (lhs1 && DECL_FUNCTION_CODE (callee1) == BUILT_IN_MEMPCPY)
1547 release_ssa_name (lhs1);
1552 /* Otherwise, if STMT1 is length 1 memcpy optimized into
1553 assignment, remove STMT1 and change memset call into
1555 gimple_stmt_iterator gsi = gsi_for_stmt (stmt1);
1557 if (!is_gimple_val (ptr1))
1558 ptr1 = force_gimple_operand_gsi (gsi_p, ptr1, true, NULL_TREE,
1559 true, GSI_SAME_STMT);
1560 gimple_call_set_fndecl (stmt2, built_in_decls [BUILT_IN_MEMCPY]);
1561 gimple_call_set_arg (stmt2, 0, ptr1);
1562 gimple_call_set_arg (stmt2, 1, new_str_cst);
1563 gimple_call_set_arg (stmt2, 2,
1564 build_int_cst (TREE_TYPE (len2), src_len));
1565 unlink_stmt_vdef (stmt1);
1566 gsi_remove (&gsi, true);
1567 release_defs (stmt1);
1568 update_stmt (stmt2);
1579 /* Checks if expression has type of one-bit precision, or is a known
1580 truth-valued expression. */
1582 truth_valued_ssa_name (tree name)
1585 tree type = TREE_TYPE (name);
1587 if (!INTEGRAL_TYPE_P (type))
1589 /* Don't check here for BOOLEAN_TYPE as the precision isn't
1590 necessarily one and so ~X is not equal to !X. */
1591 if (TYPE_PRECISION (type) == 1)
1593 def = SSA_NAME_DEF_STMT (name);
1594 if (is_gimple_assign (def))
1595 return truth_value_p (gimple_assign_rhs_code (def));
1599 /* Helper routine for simplify_bitwise_binary_1 function.
1600 Return for the SSA name NAME the expression X if it mets condition
1601 NAME = !X. Otherwise return NULL_TREE.
1602 Detected patterns for NAME = !X are:
1603 !X and X == 0 for X with integral type.
1604 X ^ 1, X != 1,or ~X for X with integral type with precision of one. */
1606 lookup_logical_inverted_value (tree name)
1609 enum tree_code code;
1612 /* If name has none-intergal type, or isn't a SSA_NAME, then
1614 if (TREE_CODE (name) != SSA_NAME
1615 || !INTEGRAL_TYPE_P (TREE_TYPE (name)))
1617 def = SSA_NAME_DEF_STMT (name);
1618 if (!is_gimple_assign (def))
1621 code = gimple_assign_rhs_code (def);
1622 op1 = gimple_assign_rhs1 (def);
1625 /* Get for EQ_EXPR or BIT_XOR_EXPR operation the second operand.
1626 If CODE isn't an EQ_EXPR, BIT_XOR_EXPR, or BIT_NOT_EXPR, then return. */
1627 if (code == EQ_EXPR || code == NE_EXPR
1628 || code == BIT_XOR_EXPR)
1629 op2 = gimple_assign_rhs2 (def);
1634 if (truth_valued_ssa_name (name))
1638 /* Check if we have X == 0 and X has an integral type. */
1639 if (!INTEGRAL_TYPE_P (TREE_TYPE (op1)))
1641 if (integer_zerop (op2))
1645 /* Check if we have X != 1 and X is a truth-valued. */
1646 if (!INTEGRAL_TYPE_P (TREE_TYPE (op1)))
1648 if (integer_onep (op2) && truth_valued_ssa_name (op1))
1652 /* Check if we have X ^ 1 and X is truth valued. */
1653 if (integer_onep (op2) && truth_valued_ssa_name (op1))
1663 /* Optimize ARG1 CODE ARG2 to a constant for bitwise binary
1664 operations CODE, if one operand has the logically inverted
1665 value of the other. */
1667 simplify_bitwise_binary_1 (enum tree_code code, tree type,
1668 tree arg1, tree arg2)
1672 /* If CODE isn't a bitwise binary operation, return NULL_TREE. */
1673 if (code != BIT_AND_EXPR && code != BIT_IOR_EXPR
1674 && code != BIT_XOR_EXPR)
1677 /* First check if operands ARG1 and ARG2 are equal. If so
1678 return NULL_TREE as this optimization is handled fold_stmt. */
1681 /* See if we have in arguments logical-not patterns. */
1682 if (((anot = lookup_logical_inverted_value (arg1)) == NULL_TREE
1684 && ((anot = lookup_logical_inverted_value (arg2)) == NULL_TREE
1689 if (code == BIT_AND_EXPR)
1690 return fold_convert (type, integer_zero_node);
1691 /* X | !X -> 1 and X ^ !X -> 1, if X is truth-valued. */
1692 if (truth_valued_ssa_name (anot))
1693 return fold_convert (type, integer_one_node);
1695 /* ??? Otherwise result is (X != 0 ? X : 1). not handled. */
1699 /* Simplify bitwise binary operations.
1700 Return true if a transformation applied, otherwise return false. */
1703 simplify_bitwise_binary (gimple_stmt_iterator *gsi)
1705 gimple stmt = gsi_stmt (*gsi);
1706 tree arg1 = gimple_assign_rhs1 (stmt);
1707 tree arg2 = gimple_assign_rhs2 (stmt);
1708 enum tree_code code = gimple_assign_rhs_code (stmt);
1710 gimple def1 = NULL, def2 = NULL;
1711 tree def1_arg1, def2_arg1;
1712 enum tree_code def1_code, def2_code;
1714 def1_code = TREE_CODE (arg1);
1716 if (TREE_CODE (arg1) == SSA_NAME)
1718 def1 = SSA_NAME_DEF_STMT (arg1);
1719 if (is_gimple_assign (def1))
1721 def1_code = gimple_assign_rhs_code (def1);
1722 def1_arg1 = gimple_assign_rhs1 (def1);
1726 def2_code = TREE_CODE (arg2);
1728 if (TREE_CODE (arg2) == SSA_NAME)
1730 def2 = SSA_NAME_DEF_STMT (arg2);
1731 if (is_gimple_assign (def2))
1733 def2_code = gimple_assign_rhs_code (def2);
1734 def2_arg1 = gimple_assign_rhs1 (def2);
1738 /* Try to fold (type) X op CST -> (type) (X op ((type-x) CST)). */
1739 if (TREE_CODE (arg2) == INTEGER_CST
1740 && CONVERT_EXPR_CODE_P (def1_code)
1741 && INTEGRAL_TYPE_P (TREE_TYPE (def1_arg1))
1742 && int_fits_type_p (arg2, TREE_TYPE (def1_arg1)))
1745 tree tem = create_tmp_reg (TREE_TYPE (def1_arg1), NULL);
1747 gimple_build_assign_with_ops (code, tem, def1_arg1,
1748 fold_convert_loc (gimple_location (stmt),
1749 TREE_TYPE (def1_arg1),
1751 tem = make_ssa_name (tem, newop);
1752 gimple_assign_set_lhs (newop, tem);
1753 gsi_insert_before (gsi, newop, GSI_SAME_STMT);
1754 gimple_assign_set_rhs_with_ops_1 (gsi, NOP_EXPR,
1755 tem, NULL_TREE, NULL_TREE);
1756 update_stmt (gsi_stmt (*gsi));
1760 /* For bitwise binary operations apply operand conversions to the
1761 binary operation result instead of to the operands. This allows
1762 to combine successive conversions and bitwise binary operations. */
1763 if (CONVERT_EXPR_CODE_P (def1_code)
1764 && CONVERT_EXPR_CODE_P (def2_code)
1765 && types_compatible_p (TREE_TYPE (def1_arg1), TREE_TYPE (def2_arg1))
1766 /* Make sure that the conversion widens the operands, or has same
1767 precision, or that it changes the operation to a bitfield
1769 && ((TYPE_PRECISION (TREE_TYPE (def1_arg1))
1770 <= TYPE_PRECISION (TREE_TYPE (arg1)))
1771 || (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (arg1)))
1773 || (TYPE_PRECISION (TREE_TYPE (arg1))
1774 != GET_MODE_PRECISION (TYPE_MODE (TREE_TYPE (arg1))))))
1777 tree tem = create_tmp_reg (TREE_TYPE (def1_arg1),
1779 newop = gimple_build_assign_with_ops (code, tem, def1_arg1, def2_arg1);
1780 tem = make_ssa_name (tem, newop);
1781 gimple_assign_set_lhs (newop, tem);
1782 gsi_insert_before (gsi, newop, GSI_SAME_STMT);
1783 gimple_assign_set_rhs_with_ops_1 (gsi, NOP_EXPR,
1784 tem, NULL_TREE, NULL_TREE);
1785 update_stmt (gsi_stmt (*gsi));
1789 /* (a | CST1) & CST2 -> (a & CST2) | (CST1 & CST2). */
1790 if (code == BIT_AND_EXPR
1791 && def1_code == BIT_IOR_EXPR
1792 && TREE_CODE (arg2) == INTEGER_CST
1793 && TREE_CODE (gimple_assign_rhs2 (def1)) == INTEGER_CST)
1795 tree cst = fold_build2 (BIT_AND_EXPR, TREE_TYPE (arg2),
1796 arg2, gimple_assign_rhs2 (def1));
1799 if (integer_zerop (cst))
1801 gimple_assign_set_rhs1 (stmt, def1_arg1);
1805 tem = create_tmp_reg (TREE_TYPE (arg2), NULL);
1806 newop = gimple_build_assign_with_ops (BIT_AND_EXPR,
1807 tem, def1_arg1, arg2);
1808 tem = make_ssa_name (tem, newop);
1809 gimple_assign_set_lhs (newop, tem);
1810 /* Make sure to re-process the new stmt as it's walking upwards. */
1811 gsi_insert_before (gsi, newop, GSI_NEW_STMT);
1812 gimple_assign_set_rhs1 (stmt, tem);
1813 gimple_assign_set_rhs2 (stmt, cst);
1814 gimple_assign_set_rhs_code (stmt, BIT_IOR_EXPR);
1819 /* Combine successive equal operations with constants. */
1820 if ((code == BIT_AND_EXPR
1821 || code == BIT_IOR_EXPR
1822 || code == BIT_XOR_EXPR)
1823 && def1_code == code
1824 && TREE_CODE (arg2) == INTEGER_CST
1825 && TREE_CODE (gimple_assign_rhs2 (def1)) == INTEGER_CST)
1827 tree cst = fold_build2 (code, TREE_TYPE (arg2),
1828 arg2, gimple_assign_rhs2 (def1));
1829 gimple_assign_set_rhs1 (stmt, def1_arg1);
1830 gimple_assign_set_rhs2 (stmt, cst);
1835 /* Canonicalize X ^ ~0 to ~X. */
1836 if (code == BIT_XOR_EXPR
1837 && TREE_CODE (arg2) == INTEGER_CST
1838 && integer_all_onesp (arg2))
1840 gimple_assign_set_rhs_with_ops (gsi, BIT_NOT_EXPR, arg1, NULL_TREE);
1841 gcc_assert (gsi_stmt (*gsi) == stmt);
1846 /* Try simple folding for X op !X, and X op X. */
1847 res = simplify_bitwise_binary_1 (code, TREE_TYPE (arg1), arg1, arg2);
1848 if (res != NULL_TREE)
1850 gimple_assign_set_rhs_from_tree (gsi, res);
1851 update_stmt (gsi_stmt (*gsi));
1859 /* Perform re-associations of the plus or minus statement STMT that are
1860 always permitted. Returns true if the CFG was changed. */
1863 associate_plusminus (gimple stmt)
1865 tree rhs1 = gimple_assign_rhs1 (stmt);
1866 tree rhs2 = gimple_assign_rhs2 (stmt);
1867 enum tree_code code = gimple_assign_rhs_code (stmt);
1868 gimple_stmt_iterator gsi;
1871 /* We can't reassociate at all for saturating types. */
1872 if (TYPE_SATURATING (TREE_TYPE (rhs1)))
1875 /* First contract negates. */
1880 /* A +- (-B) -> A -+ B. */
1881 if (TREE_CODE (rhs2) == SSA_NAME)
1883 gimple def_stmt = SSA_NAME_DEF_STMT (rhs2);
1884 if (is_gimple_assign (def_stmt)
1885 && gimple_assign_rhs_code (def_stmt) == NEGATE_EXPR
1886 && can_propagate_from (def_stmt))
1888 code = (code == MINUS_EXPR) ? PLUS_EXPR : MINUS_EXPR;
1889 gimple_assign_set_rhs_code (stmt, code);
1890 rhs2 = gimple_assign_rhs1 (def_stmt);
1891 gimple_assign_set_rhs2 (stmt, rhs2);
1892 gimple_set_modified (stmt, true);
1897 /* (-A) + B -> B - A. */
1898 if (TREE_CODE (rhs1) == SSA_NAME
1899 && code == PLUS_EXPR)
1901 gimple def_stmt = SSA_NAME_DEF_STMT (rhs1);
1902 if (is_gimple_assign (def_stmt)
1903 && gimple_assign_rhs_code (def_stmt) == NEGATE_EXPR
1904 && can_propagate_from (def_stmt))
1907 gimple_assign_set_rhs_code (stmt, code);
1909 gimple_assign_set_rhs1 (stmt, rhs1);
1910 rhs2 = gimple_assign_rhs1 (def_stmt);
1911 gimple_assign_set_rhs2 (stmt, rhs2);
1912 gimple_set_modified (stmt, true);
1919 /* We can't reassociate floating-point or fixed-point plus or minus
1920 because of saturation to +-Inf. */
1921 if (FLOAT_TYPE_P (TREE_TYPE (rhs1))
1922 || FIXED_POINT_TYPE_P (TREE_TYPE (rhs1)))
1925 /* Second match patterns that allow contracting a plus-minus pair
1926 irrespective of overflow issues.
1928 (A +- B) - A -> +- B
1930 (CST +- A) +- CST -> CST +- A
1931 (A + CST) +- CST -> A + CST
1934 A - (A +- B) -> -+ B
1935 A +- (B +- A) -> +- B
1936 CST +- (CST +- A) -> CST +- A
1937 CST +- (A +- CST) -> CST +- A
1940 via commutating the addition and contracting operations to zero
1941 by reassociation. */
1943 gsi = gsi_for_stmt (stmt);
1944 if (TREE_CODE (rhs1) == SSA_NAME)
1946 gimple def_stmt = SSA_NAME_DEF_STMT (rhs1);
1947 if (is_gimple_assign (def_stmt) && can_propagate_from (def_stmt))
1949 enum tree_code def_code = gimple_assign_rhs_code (def_stmt);
1950 if (def_code == PLUS_EXPR
1951 || def_code == MINUS_EXPR)
1953 tree def_rhs1 = gimple_assign_rhs1 (def_stmt);
1954 tree def_rhs2 = gimple_assign_rhs2 (def_stmt);
1955 if (operand_equal_p (def_rhs1, rhs2, 0)
1956 && code == MINUS_EXPR)
1958 /* (A +- B) - A -> +- B. */
1959 code = ((def_code == PLUS_EXPR)
1960 ? TREE_CODE (def_rhs2) : NEGATE_EXPR);
1963 gimple_assign_set_rhs_with_ops (&gsi, code, rhs1, NULL_TREE);
1964 gcc_assert (gsi_stmt (gsi) == stmt);
1965 gimple_set_modified (stmt, true);
1967 else if (operand_equal_p (def_rhs2, rhs2, 0)
1968 && code != def_code)
1970 /* (A +- B) -+ B -> A. */
1971 code = TREE_CODE (def_rhs1);
1974 gimple_assign_set_rhs_with_ops (&gsi, code, rhs1, NULL_TREE);
1975 gcc_assert (gsi_stmt (gsi) == stmt);
1976 gimple_set_modified (stmt, true);
1978 else if (TREE_CODE (rhs2) == INTEGER_CST
1979 && TREE_CODE (def_rhs1) == INTEGER_CST)
1981 /* (CST +- A) +- CST -> CST +- A. */
1982 tree cst = fold_binary (code, TREE_TYPE (rhs1),
1984 if (cst && !TREE_OVERFLOW (cst))
1987 gimple_assign_set_rhs_code (stmt, code);
1989 gimple_assign_set_rhs1 (stmt, rhs1);
1991 gimple_assign_set_rhs2 (stmt, rhs2);
1992 gimple_set_modified (stmt, true);
1995 else if (TREE_CODE (rhs2) == INTEGER_CST
1996 && TREE_CODE (def_rhs2) == INTEGER_CST
1997 && def_code == PLUS_EXPR)
1999 /* (A + CST) +- CST -> A + CST. */
2000 tree cst = fold_binary (code, TREE_TYPE (rhs1),
2002 if (cst && !TREE_OVERFLOW (cst))
2005 gimple_assign_set_rhs_code (stmt, code);
2007 gimple_assign_set_rhs1 (stmt, rhs1);
2009 gimple_assign_set_rhs2 (stmt, rhs2);
2010 gimple_set_modified (stmt, true);
2014 else if (def_code == BIT_NOT_EXPR
2015 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
2017 tree def_rhs1 = gimple_assign_rhs1 (def_stmt);
2018 if (code == PLUS_EXPR
2019 && operand_equal_p (def_rhs1, rhs2, 0))
2023 rhs1 = build_int_cst_type (TREE_TYPE (rhs2), -1);
2025 gimple_assign_set_rhs_with_ops (&gsi, code, rhs1, NULL_TREE);
2026 gcc_assert (gsi_stmt (gsi) == stmt);
2027 gimple_set_modified (stmt, true);
2029 else if (code == PLUS_EXPR
2030 && integer_onep (rhs1))
2036 gimple_assign_set_rhs_with_ops (&gsi, code, rhs1, NULL_TREE);
2037 gcc_assert (gsi_stmt (gsi) == stmt);
2038 gimple_set_modified (stmt, true);
2044 if (rhs2 && TREE_CODE (rhs2) == SSA_NAME)
2046 gimple def_stmt = SSA_NAME_DEF_STMT (rhs2);
2047 if (is_gimple_assign (def_stmt) && can_propagate_from (def_stmt))
2049 enum tree_code def_code = gimple_assign_rhs_code (def_stmt);
2050 if (def_code == PLUS_EXPR
2051 || def_code == MINUS_EXPR)
2053 tree def_rhs1 = gimple_assign_rhs1 (def_stmt);
2054 tree def_rhs2 = gimple_assign_rhs2 (def_stmt);
2055 if (operand_equal_p (def_rhs1, rhs1, 0)
2056 && code == MINUS_EXPR)
2058 /* A - (A +- B) -> -+ B. */
2059 code = ((def_code == PLUS_EXPR)
2060 ? NEGATE_EXPR : TREE_CODE (def_rhs2));
2063 gimple_assign_set_rhs_with_ops (&gsi, code, rhs1, NULL_TREE);
2064 gcc_assert (gsi_stmt (gsi) == stmt);
2065 gimple_set_modified (stmt, true);
2067 else if (operand_equal_p (def_rhs2, rhs1, 0)
2068 && code != def_code)
2070 /* A +- (B +- A) -> +- B. */
2071 code = ((code == PLUS_EXPR)
2072 ? TREE_CODE (def_rhs1) : NEGATE_EXPR);
2075 gimple_assign_set_rhs_with_ops (&gsi, code, rhs1, NULL_TREE);
2076 gcc_assert (gsi_stmt (gsi) == stmt);
2077 gimple_set_modified (stmt, true);
2079 else if (TREE_CODE (rhs1) == INTEGER_CST
2080 && TREE_CODE (def_rhs1) == INTEGER_CST)
2082 /* CST +- (CST +- A) -> CST +- A. */
2083 tree cst = fold_binary (code, TREE_TYPE (rhs2),
2085 if (cst && !TREE_OVERFLOW (cst))
2087 code = (code == def_code ? PLUS_EXPR : MINUS_EXPR);
2088 gimple_assign_set_rhs_code (stmt, code);
2090 gimple_assign_set_rhs1 (stmt, rhs1);
2092 gimple_assign_set_rhs2 (stmt, rhs2);
2093 gimple_set_modified (stmt, true);
2096 else if (TREE_CODE (rhs1) == INTEGER_CST
2097 && TREE_CODE (def_rhs2) == INTEGER_CST)
2099 /* CST +- (A +- CST) -> CST +- A. */
2100 tree cst = fold_binary (def_code == code
2101 ? PLUS_EXPR : MINUS_EXPR,
2104 if (cst && !TREE_OVERFLOW (cst))
2107 gimple_assign_set_rhs1 (stmt, rhs1);
2109 gimple_assign_set_rhs2 (stmt, rhs2);
2110 gimple_set_modified (stmt, true);
2114 else if (def_code == BIT_NOT_EXPR
2115 && INTEGRAL_TYPE_P (TREE_TYPE (rhs2)))
2117 tree def_rhs1 = gimple_assign_rhs1 (def_stmt);
2118 if (code == PLUS_EXPR
2119 && operand_equal_p (def_rhs1, rhs1, 0))
2123 rhs1 = build_int_cst_type (TREE_TYPE (rhs1), -1);
2125 gimple_assign_set_rhs_with_ops (&gsi, code, rhs1, NULL_TREE);
2126 gcc_assert (gsi_stmt (gsi) == stmt);
2127 gimple_set_modified (stmt, true);
2134 if (gimple_modified_p (stmt))
2136 fold_stmt_inplace (stmt);
2138 if (maybe_clean_or_replace_eh_stmt (stmt, stmt)
2139 && gimple_purge_dead_eh_edges (gimple_bb (stmt)))
2146 /* Combine two conversions in a row for the second conversion at *GSI.
2147 Returns 1 if there were any changes made, 2 if cfg-cleanup needs to
2148 run. Else it returns 0. */
2151 combine_conversions (gimple_stmt_iterator *gsi)
2153 gimple stmt = gsi_stmt (*gsi);
2156 enum tree_code code = gimple_assign_rhs_code (stmt);
2158 gcc_checking_assert (CONVERT_EXPR_CODE_P (code)
2159 || code == FLOAT_EXPR
2160 || code == FIX_TRUNC_EXPR);
2162 lhs = gimple_assign_lhs (stmt);
2163 op0 = gimple_assign_rhs1 (stmt);
2164 if (useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (op0)))
2166 gimple_assign_set_rhs_code (stmt, TREE_CODE (op0));
2170 if (TREE_CODE (op0) != SSA_NAME)
2173 def_stmt = SSA_NAME_DEF_STMT (op0);
2174 if (!is_gimple_assign (def_stmt))
2177 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)))
2179 tree defop0 = gimple_assign_rhs1 (def_stmt);
2180 tree type = TREE_TYPE (lhs);
2181 tree inside_type = TREE_TYPE (defop0);
2182 tree inter_type = TREE_TYPE (op0);
2183 int inside_int = INTEGRAL_TYPE_P (inside_type);
2184 int inside_ptr = POINTER_TYPE_P (inside_type);
2185 int inside_float = FLOAT_TYPE_P (inside_type);
2186 int inside_vec = TREE_CODE (inside_type) == VECTOR_TYPE;
2187 unsigned int inside_prec = TYPE_PRECISION (inside_type);
2188 int inside_unsignedp = TYPE_UNSIGNED (inside_type);
2189 int inter_int = INTEGRAL_TYPE_P (inter_type);
2190 int inter_ptr = POINTER_TYPE_P (inter_type);
2191 int inter_float = FLOAT_TYPE_P (inter_type);
2192 int inter_vec = TREE_CODE (inter_type) == VECTOR_TYPE;
2193 unsigned int inter_prec = TYPE_PRECISION (inter_type);
2194 int inter_unsignedp = TYPE_UNSIGNED (inter_type);
2195 int final_int = INTEGRAL_TYPE_P (type);
2196 int final_ptr = POINTER_TYPE_P (type);
2197 int final_float = FLOAT_TYPE_P (type);
2198 int final_vec = TREE_CODE (type) == VECTOR_TYPE;
2199 unsigned int final_prec = TYPE_PRECISION (type);
2200 int final_unsignedp = TYPE_UNSIGNED (type);
2202 /* In addition to the cases of two conversions in a row
2203 handled below, if we are converting something to its own
2204 type via an object of identical or wider precision, neither
2205 conversion is needed. */
2206 if (useless_type_conversion_p (type, inside_type)
2207 && (((inter_int || inter_ptr) && final_int)
2208 || (inter_float && final_float))
2209 && inter_prec >= final_prec)
2211 gimple_assign_set_rhs1 (stmt, unshare_expr (defop0));
2212 gimple_assign_set_rhs_code (stmt, TREE_CODE (defop0));
2214 return remove_prop_source_from_use (op0) ? 2 : 1;
2217 /* Likewise, if the intermediate and initial types are either both
2218 float or both integer, we don't need the middle conversion if the
2219 former is wider than the latter and doesn't change the signedness
2220 (for integers). Avoid this if the final type is a pointer since
2221 then we sometimes need the middle conversion. Likewise if the
2222 final type has a precision not equal to the size of its mode. */
2223 if (((inter_int && inside_int)
2224 || (inter_float && inside_float)
2225 || (inter_vec && inside_vec))
2226 && inter_prec >= inside_prec
2227 && (inter_float || inter_vec
2228 || inter_unsignedp == inside_unsignedp)
2229 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (type))
2230 && TYPE_MODE (type) == TYPE_MODE (inter_type))
2232 && (! final_vec || inter_prec == inside_prec))
2234 gimple_assign_set_rhs1 (stmt, defop0);
2236 return remove_prop_source_from_use (op0) ? 2 : 1;
2239 /* If we have a sign-extension of a zero-extended value, we can
2240 replace that by a single zero-extension. */
2241 if (inside_int && inter_int && final_int
2242 && inside_prec < inter_prec && inter_prec < final_prec
2243 && inside_unsignedp && !inter_unsignedp)
2245 gimple_assign_set_rhs1 (stmt, defop0);
2247 return remove_prop_source_from_use (op0) ? 2 : 1;
2250 /* Two conversions in a row are not needed unless:
2251 - some conversion is floating-point (overstrict for now), or
2252 - some conversion is a vector (overstrict for now), or
2253 - the intermediate type is narrower than both initial and
2255 - the intermediate type and innermost type differ in signedness,
2256 and the outermost type is wider than the intermediate, or
2257 - the initial type is a pointer type and the precisions of the
2258 intermediate and final types differ, or
2259 - the final type is a pointer type and the precisions of the
2260 initial and intermediate types differ. */
2261 if (! inside_float && ! inter_float && ! final_float
2262 && ! inside_vec && ! inter_vec && ! final_vec
2263 && (inter_prec >= inside_prec || inter_prec >= final_prec)
2264 && ! (inside_int && inter_int
2265 && inter_unsignedp != inside_unsignedp
2266 && inter_prec < final_prec)
2267 && ((inter_unsignedp && inter_prec > inside_prec)
2268 == (final_unsignedp && final_prec > inter_prec))
2269 && ! (inside_ptr && inter_prec != final_prec)
2270 && ! (final_ptr && inside_prec != inter_prec)
2271 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (type))
2272 && TYPE_MODE (type) == TYPE_MODE (inter_type)))
2274 gimple_assign_set_rhs1 (stmt, defop0);
2276 return remove_prop_source_from_use (op0) ? 2 : 1;
2279 /* A truncation to an unsigned type should be canonicalized as
2280 bitwise and of a mask. */
2281 if (final_int && inter_int && inside_int
2282 && final_prec == inside_prec
2283 && final_prec > inter_prec
2287 tem = fold_build2 (BIT_AND_EXPR, inside_type,
2290 (inside_type, double_int_mask (inter_prec)));
2291 if (!useless_type_conversion_p (type, inside_type))
2293 tem = force_gimple_operand_gsi (gsi, tem, true, NULL_TREE, true,
2295 gimple_assign_set_rhs1 (stmt, tem);
2298 gimple_assign_set_rhs_from_tree (gsi, tem);
2299 update_stmt (gsi_stmt (*gsi));
2307 /* Main entry point for the forward propagation and statement combine
2311 ssa_forward_propagate_and_combine (void)
2314 unsigned int todoflags = 0;
2316 cfg_changed = false;
2320 gimple_stmt_iterator gsi, prev;
2321 bool prev_initialized;
2323 /* Apply forward propagation to all stmts in the basic-block.
2324 Note we update GSI within the loop as necessary. */
2325 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); )
2327 gimple stmt = gsi_stmt (gsi);
2329 enum tree_code code;
2331 if (!is_gimple_assign (stmt))
2337 lhs = gimple_assign_lhs (stmt);
2338 rhs = gimple_assign_rhs1 (stmt);
2339 code = gimple_assign_rhs_code (stmt);
2340 if (TREE_CODE (lhs) != SSA_NAME
2341 || has_zero_uses (lhs))
2347 /* If this statement sets an SSA_NAME to an address,
2348 try to propagate the address into the uses of the SSA_NAME. */
2349 if (code == ADDR_EXPR
2350 /* Handle pointer conversions on invariant addresses
2351 as well, as this is valid gimple. */
2352 || (CONVERT_EXPR_CODE_P (code)
2353 && TREE_CODE (rhs) == ADDR_EXPR
2354 && POINTER_TYPE_P (TREE_TYPE (lhs))))
2356 tree base = get_base_address (TREE_OPERAND (rhs, 0));
2359 || decl_address_invariant_p (base))
2360 && !stmt_references_abnormal_ssa_name (stmt)
2361 && forward_propagate_addr_expr (lhs, rhs))
2363 release_defs (stmt);
2364 todoflags |= TODO_remove_unused_locals;
2365 gsi_remove (&gsi, true);
2370 else if (code == POINTER_PLUS_EXPR && can_propagate_from (stmt))
2372 if (TREE_CODE (gimple_assign_rhs2 (stmt)) == INTEGER_CST
2373 /* ??? Better adjust the interface to that function
2374 instead of building new trees here. */
2375 && forward_propagate_addr_expr
2379 fold_build2 (MEM_REF,
2380 TREE_TYPE (TREE_TYPE (rhs)),
2384 gimple_assign_rhs2 (stmt))))))
2386 release_defs (stmt);
2387 todoflags |= TODO_remove_unused_locals;
2388 gsi_remove (&gsi, true);
2390 else if (is_gimple_min_invariant (rhs))
2392 /* Make sure to fold &a[0] + off_1 here. */
2393 fold_stmt_inplace (stmt);
2395 if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR)
2401 else if (TREE_CODE_CLASS (code) == tcc_comparison)
2403 forward_propagate_comparison (stmt);
2410 /* Combine stmts with the stmts defining their operands.
2411 Note we update GSI within the loop as necessary. */
2412 prev_initialized = false;
2413 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi);)
2415 gimple stmt = gsi_stmt (gsi);
2416 bool changed = false;
2418 switch (gimple_code (stmt))
2422 tree rhs1 = gimple_assign_rhs1 (stmt);
2423 enum tree_code code = gimple_assign_rhs_code (stmt);
2425 if ((code == BIT_NOT_EXPR
2426 || code == NEGATE_EXPR)
2427 && TREE_CODE (rhs1) == SSA_NAME)
2428 changed = simplify_not_neg_expr (&gsi);
2429 else if (code == COND_EXPR)
2431 /* In this case the entire COND_EXPR is in rhs1. */
2433 fold_defer_overflow_warnings ();
2434 did_something = forward_propagate_into_cond (&gsi);
2435 stmt = gsi_stmt (gsi);
2436 if (did_something == 2)
2438 fold_undefer_overflow_warnings
2439 (!TREE_NO_WARNING (rhs1) && did_something, stmt,
2440 WARN_STRICT_OVERFLOW_CONDITIONAL);
2441 changed = did_something != 0;
2443 else if (TREE_CODE_CLASS (code) == tcc_comparison)
2445 bool no_warning = gimple_no_warning_p (stmt);
2447 fold_defer_overflow_warnings ();
2448 did_something = forward_propagate_into_comparison (&gsi);
2449 if (did_something == 2)
2451 fold_undefer_overflow_warnings
2452 (!no_warning && changed,
2453 stmt, WARN_STRICT_OVERFLOW_CONDITIONAL);
2454 changed = did_something != 0;
2456 else if (code == BIT_AND_EXPR
2457 || code == BIT_IOR_EXPR
2458 || code == BIT_XOR_EXPR)
2459 changed = simplify_bitwise_binary (&gsi);
2460 else if (code == PLUS_EXPR
2461 || code == MINUS_EXPR)
2462 changed = associate_plusminus (stmt);
2463 else if (CONVERT_EXPR_CODE_P (code)
2464 || code == FLOAT_EXPR
2465 || code == FIX_TRUNC_EXPR)
2467 int did_something = combine_conversions (&gsi);
2468 if (did_something == 2)
2470 changed = did_something != 0;
2476 changed = simplify_gimple_switch (stmt);
2482 fold_defer_overflow_warnings ();
2483 did_something = forward_propagate_into_gimple_cond (stmt);
2484 if (did_something == 2)
2486 fold_undefer_overflow_warnings
2487 (did_something, stmt, WARN_STRICT_OVERFLOW_CONDITIONAL);
2488 changed = did_something != 0;
2494 tree callee = gimple_call_fndecl (stmt);
2495 if (callee != NULL_TREE
2496 && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
2497 changed = simplify_builtin_call (&gsi, callee);
2506 /* If the stmt changed then re-visit it and the statements
2507 inserted before it. */
2508 if (!prev_initialized)
2509 gsi = gsi_start_bb (bb);
2519 prev_initialized = true;
2526 todoflags |= TODO_cleanup_cfg;
2533 gate_forwprop (void)
2535 return flag_tree_forwprop;
2538 struct gimple_opt_pass pass_forwprop =
2542 "forwprop", /* name */
2543 gate_forwprop, /* gate */
2544 ssa_forward_propagate_and_combine, /* execute */
2547 0, /* static_pass_number */
2548 TV_TREE_FORWPROP, /* tv_id */
2549 PROP_cfg | PROP_ssa, /* properties_required */
2550 0, /* properties_provided */
2551 0, /* properties_destroyed */
2552 0, /* todo_flags_start */
2555 | TODO_verify_ssa /* todo_flags_finish */