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 chain of dead statements starting at the definition of
299 NAME. The chain is linked via the first operand of the defining statements.
300 If NAME was replaced in its only use then this function can be used
301 to clean up dead stmts. The function handles already released SSA
303 Returns true if cleanup-cfg has to run. */
306 remove_prop_source_from_use (tree name)
308 gimple_stmt_iterator gsi;
310 bool cfg_changed = false;
315 if (SSA_NAME_IN_FREE_LIST (name)
316 || SSA_NAME_IS_DEFAULT_DEF (name)
317 || !has_zero_uses (name))
320 stmt = SSA_NAME_DEF_STMT (name);
321 if (gimple_code (stmt) == GIMPLE_PHI
322 || gimple_has_side_effects (stmt))
325 bb = gimple_bb (stmt);
326 gsi = gsi_for_stmt (stmt);
327 unlink_stmt_vdef (stmt);
328 gsi_remove (&gsi, true);
330 cfg_changed |= gimple_purge_dead_eh_edges (bb);
332 name = is_gimple_assign (stmt) ? gimple_assign_rhs1 (stmt) : NULL_TREE;
333 } while (name && TREE_CODE (name) == SSA_NAME);
338 /* Return the rhs of a gimple_assign STMT in a form of a single tree,
339 converted to type TYPE.
341 This should disappear, but is needed so we can combine expressions and use
342 the fold() interfaces. Long term, we need to develop folding and combine
343 routines that deal with gimple exclusively . */
346 rhs_to_tree (tree type, gimple stmt)
348 location_t loc = gimple_location (stmt);
349 enum tree_code code = gimple_assign_rhs_code (stmt);
350 if (get_gimple_rhs_class (code) == GIMPLE_TERNARY_RHS)
351 return fold_build3_loc (loc, code, type, gimple_assign_rhs1 (stmt),
352 gimple_assign_rhs2 (stmt),
353 gimple_assign_rhs3 (stmt));
354 else if (get_gimple_rhs_class (code) == GIMPLE_BINARY_RHS)
355 return fold_build2_loc (loc, code, type, gimple_assign_rhs1 (stmt),
356 gimple_assign_rhs2 (stmt));
357 else if (get_gimple_rhs_class (code) == GIMPLE_UNARY_RHS)
358 return build1 (code, type, gimple_assign_rhs1 (stmt));
359 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS)
360 return gimple_assign_rhs1 (stmt);
365 /* Combine OP0 CODE OP1 in the context of a COND_EXPR. Returns
366 the folded result in a form suitable for COND_EXPR_COND or
367 NULL_TREE, if there is no suitable simplified form. If
368 INVARIANT_ONLY is true only gimple_min_invariant results are
369 considered simplified. */
372 combine_cond_expr_cond (gimple stmt, enum tree_code code, tree type,
373 tree op0, tree op1, bool invariant_only)
377 gcc_assert (TREE_CODE_CLASS (code) == tcc_comparison);
379 fold_defer_overflow_warnings ();
380 t = fold_binary_loc (gimple_location (stmt), code, type, op0, op1);
383 fold_undefer_overflow_warnings (false, NULL, 0);
387 /* Require that we got a boolean type out if we put one in. */
388 gcc_assert (TREE_CODE (TREE_TYPE (t)) == TREE_CODE (type));
390 /* Canonicalize the combined condition for use in a COND_EXPR. */
391 t = canonicalize_cond_expr_cond (t);
393 /* Bail out if we required an invariant but didn't get one. */
394 if (!t || (invariant_only && !is_gimple_min_invariant (t)))
396 fold_undefer_overflow_warnings (false, NULL, 0);
400 fold_undefer_overflow_warnings (!gimple_no_warning_p (stmt), stmt, 0);
405 /* Combine the comparison OP0 CODE OP1 at LOC with the defining statements
406 of its operand. Return a new comparison tree or NULL_TREE if there
407 were no simplifying combines. */
410 forward_propagate_into_comparison_1 (gimple stmt,
411 enum tree_code code, tree type,
414 tree tmp = NULL_TREE;
415 tree rhs0 = NULL_TREE, rhs1 = NULL_TREE;
416 bool single_use0_p = false, single_use1_p = false;
418 /* For comparisons use the first operand, that is likely to
419 simplify comparisons against constants. */
420 if (TREE_CODE (op0) == SSA_NAME)
422 gimple def_stmt = get_prop_source_stmt (op0, false, &single_use0_p);
423 if (def_stmt && can_propagate_from (def_stmt))
425 rhs0 = rhs_to_tree (TREE_TYPE (op1), def_stmt);
426 tmp = combine_cond_expr_cond (stmt, code, type,
427 rhs0, op1, !single_use0_p);
433 /* If that wasn't successful, try the second operand. */
434 if (TREE_CODE (op1) == SSA_NAME)
436 gimple def_stmt = get_prop_source_stmt (op1, false, &single_use1_p);
437 if (def_stmt && can_propagate_from (def_stmt))
439 rhs1 = rhs_to_tree (TREE_TYPE (op0), def_stmt);
440 tmp = combine_cond_expr_cond (stmt, code, type,
441 op0, rhs1, !single_use1_p);
447 /* If that wasn't successful either, try both operands. */
448 if (rhs0 != NULL_TREE
449 && rhs1 != NULL_TREE)
450 tmp = combine_cond_expr_cond (stmt, code, type,
452 !(single_use0_p && single_use1_p));
457 /* Propagate from the ssa name definition statements of the assignment
458 from a comparison at *GSI into the conditional if that simplifies it.
459 Returns 1 if the stmt was modified and 2 if the CFG needs cleanup,
460 otherwise returns 0. */
463 forward_propagate_into_comparison (gimple_stmt_iterator *gsi)
465 gimple stmt = gsi_stmt (*gsi);
467 bool cfg_changed = false;
468 tree rhs1 = gimple_assign_rhs1 (stmt);
469 tree rhs2 = gimple_assign_rhs2 (stmt);
471 /* Combine the comparison with defining statements. */
472 tmp = forward_propagate_into_comparison_1 (stmt,
473 gimple_assign_rhs_code (stmt),
475 (gimple_assign_lhs (stmt)),
479 gimple_assign_set_rhs_from_tree (gsi, tmp);
481 update_stmt (gsi_stmt (*gsi));
483 if (TREE_CODE (rhs1) == SSA_NAME)
484 cfg_changed |= remove_prop_source_from_use (rhs1);
485 if (TREE_CODE (rhs2) == SSA_NAME)
486 cfg_changed |= remove_prop_source_from_use (rhs2);
487 return cfg_changed ? 2 : 1;
493 /* Propagate from the ssa name definition statements of COND_EXPR
494 in GIMPLE_COND statement STMT into the conditional if that simplifies it.
495 Returns zero if no statement was changed, one if there were
496 changes and two if cfg_cleanup needs to run.
498 This must be kept in sync with forward_propagate_into_cond. */
501 forward_propagate_into_gimple_cond (gimple stmt)
504 enum tree_code code = gimple_cond_code (stmt);
505 bool cfg_changed = false;
506 tree rhs1 = gimple_cond_lhs (stmt);
507 tree rhs2 = gimple_cond_rhs (stmt);
509 /* We can do tree combining on SSA_NAME and comparison expressions. */
510 if (TREE_CODE_CLASS (gimple_cond_code (stmt)) != tcc_comparison)
513 tmp = forward_propagate_into_comparison_1 (stmt, code,
518 if (dump_file && tmp)
520 fprintf (dump_file, " Replaced '");
521 print_gimple_expr (dump_file, stmt, 0, 0);
522 fprintf (dump_file, "' with '");
523 print_generic_expr (dump_file, tmp, 0);
524 fprintf (dump_file, "'\n");
527 gimple_cond_set_condition_from_tree (stmt, unshare_expr (tmp));
530 if (TREE_CODE (rhs1) == SSA_NAME)
531 cfg_changed |= remove_prop_source_from_use (rhs1);
532 if (TREE_CODE (rhs2) == SSA_NAME)
533 cfg_changed |= remove_prop_source_from_use (rhs2);
534 return (cfg_changed || is_gimple_min_invariant (tmp)) ? 2 : 1;
537 /* Canonicalize _Bool == 0 and _Bool != 1 to _Bool != 0 by swapping edges. */
538 if ((TREE_CODE (TREE_TYPE (rhs1)) == BOOLEAN_TYPE
539 || (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))
540 && TYPE_PRECISION (TREE_TYPE (rhs1)) == 1))
542 && integer_zerop (rhs2))
544 && integer_onep (rhs2))))
546 basic_block bb = gimple_bb (stmt);
547 gimple_cond_set_code (stmt, NE_EXPR);
548 gimple_cond_set_rhs (stmt, build_zero_cst (TREE_TYPE (rhs1)));
549 EDGE_SUCC (bb, 0)->flags ^= (EDGE_TRUE_VALUE|EDGE_FALSE_VALUE);
550 EDGE_SUCC (bb, 1)->flags ^= (EDGE_TRUE_VALUE|EDGE_FALSE_VALUE);
558 /* Propagate from the ssa name definition statements of COND_EXPR
559 in the rhs of statement STMT into the conditional if that simplifies it.
560 Returns true zero if the stmt was changed. */
563 forward_propagate_into_cond (gimple_stmt_iterator *gsi_p)
565 gimple stmt = gsi_stmt (*gsi_p);
566 tree tmp = NULL_TREE;
567 tree cond = gimple_assign_rhs1 (stmt);
570 /* We can do tree combining on SSA_NAME and comparison expressions. */
571 if (COMPARISON_CLASS_P (cond))
572 tmp = forward_propagate_into_comparison_1 (stmt, TREE_CODE (cond),
574 TREE_OPERAND (cond, 0),
575 TREE_OPERAND (cond, 1));
576 else if (TREE_CODE (cond) == SSA_NAME)
580 gimple def_stmt = get_prop_source_stmt (name, true, NULL);
581 if (!def_stmt || !can_propagate_from (def_stmt))
584 code = gimple_assign_rhs_code (def_stmt);
585 if (TREE_CODE_CLASS (code) == tcc_comparison)
586 tmp = fold_build2_loc (gimple_location (def_stmt),
589 gimple_assign_rhs1 (def_stmt),
590 gimple_assign_rhs2 (def_stmt));
591 else if ((code == BIT_NOT_EXPR
592 && TYPE_PRECISION (TREE_TYPE (cond)) == 1)
593 || (code == BIT_XOR_EXPR
594 && integer_onep (gimple_assign_rhs2 (def_stmt))))
596 tmp = gimple_assign_rhs1 (def_stmt);
603 if (dump_file && tmp)
605 fprintf (dump_file, " Replaced '");
606 print_generic_expr (dump_file, cond, 0);
607 fprintf (dump_file, "' with '");
608 print_generic_expr (dump_file, tmp, 0);
609 fprintf (dump_file, "'\n");
612 if (integer_onep (tmp))
613 gimple_assign_set_rhs_from_tree (gsi_p, gimple_assign_rhs2 (stmt));
614 else if (integer_zerop (tmp))
615 gimple_assign_set_rhs_from_tree (gsi_p, gimple_assign_rhs3 (stmt));
618 gimple_assign_set_rhs1 (stmt, unshare_expr (tmp));
621 tree t = gimple_assign_rhs2 (stmt);
622 gimple_assign_set_rhs2 (stmt, gimple_assign_rhs3 (stmt));
623 gimple_assign_set_rhs3 (stmt, t);
626 stmt = gsi_stmt (*gsi_p);
635 /* We've just substituted an ADDR_EXPR into stmt. Update all the
636 relevant data structures to match. */
639 tidy_after_forward_propagate_addr (gimple stmt)
641 /* We may have turned a trapping insn into a non-trapping insn. */
642 if (maybe_clean_or_replace_eh_stmt (stmt, stmt)
643 && gimple_purge_dead_eh_edges (gimple_bb (stmt)))
646 if (TREE_CODE (gimple_assign_rhs1 (stmt)) == ADDR_EXPR)
647 recompute_tree_invariant_for_addr_expr (gimple_assign_rhs1 (stmt));
650 /* DEF_RHS contains the address of the 0th element in an array.
651 USE_STMT uses type of DEF_RHS to compute the address of an
652 arbitrary element within the array. The (variable) byte offset
653 of the element is contained in OFFSET.
655 We walk back through the use-def chains of OFFSET to verify that
656 it is indeed computing the offset of an element within the array
657 and extract the index corresponding to the given byte offset.
659 We then try to fold the entire address expression into a form
662 If we are successful, we replace the right hand side of USE_STMT
663 with the new address computation. */
666 forward_propagate_addr_into_variable_array_index (tree offset,
668 gimple_stmt_iterator *use_stmt_gsi)
671 gimple offset_def, use_stmt = gsi_stmt (*use_stmt_gsi);
674 if (TREE_CODE (TREE_OPERAND (def_rhs, 0)) == ARRAY_REF)
675 tunit = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (def_rhs)));
676 else if (TREE_CODE (TREE_TYPE (TREE_OPERAND (def_rhs, 0))) == ARRAY_TYPE)
677 tunit = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (TREE_TYPE (def_rhs))));
680 if (!host_integerp (tunit, 1))
683 /* Get the offset's defining statement. */
684 offset_def = SSA_NAME_DEF_STMT (offset);
686 /* Try to find an expression for a proper index. This is either a
687 multiplication expression by the element size or just the ssa name we came
688 along in case the element size is one. In that case, however, we do not
689 allow multiplications because they can be computing index to a higher
690 level dimension (PR 37861). */
691 if (integer_onep (tunit))
693 if (is_gimple_assign (offset_def)
694 && gimple_assign_rhs_code (offset_def) == MULT_EXPR)
701 /* The statement which defines OFFSET before type conversion
702 must be a simple GIMPLE_ASSIGN. */
703 if (!is_gimple_assign (offset_def))
706 /* The RHS of the statement which defines OFFSET must be a
707 multiplication of an object by the size of the array elements.
708 This implicitly verifies that the size of the array elements
710 if (gimple_assign_rhs_code (offset_def) == MULT_EXPR
711 && TREE_CODE (gimple_assign_rhs2 (offset_def)) == INTEGER_CST
712 && tree_int_cst_equal (gimple_assign_rhs2 (offset_def), tunit))
714 /* The first operand to the MULT_EXPR is the desired index. */
715 index = gimple_assign_rhs1 (offset_def);
717 /* If we have idx * tunit + CST * tunit re-associate that. */
718 else if ((gimple_assign_rhs_code (offset_def) == PLUS_EXPR
719 || gimple_assign_rhs_code (offset_def) == MINUS_EXPR)
720 && TREE_CODE (gimple_assign_rhs1 (offset_def)) == SSA_NAME
721 && TREE_CODE (gimple_assign_rhs2 (offset_def)) == INTEGER_CST
722 && (tmp = div_if_zero_remainder (EXACT_DIV_EXPR,
723 gimple_assign_rhs2 (offset_def),
724 tunit)) != NULL_TREE)
726 gimple offset_def2 = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (offset_def));
727 if (is_gimple_assign (offset_def2)
728 && gimple_assign_rhs_code (offset_def2) == MULT_EXPR
729 && TREE_CODE (gimple_assign_rhs2 (offset_def2)) == INTEGER_CST
730 && tree_int_cst_equal (gimple_assign_rhs2 (offset_def2), tunit))
732 index = fold_build2 (gimple_assign_rhs_code (offset_def),
734 gimple_assign_rhs1 (offset_def2), tmp);
743 /* Replace the pointer addition with array indexing. */
744 index = force_gimple_operand_gsi (use_stmt_gsi, index, true, NULL_TREE,
745 true, GSI_SAME_STMT);
746 if (TREE_CODE (TREE_OPERAND (def_rhs, 0)) == ARRAY_REF)
748 new_rhs = unshare_expr (def_rhs);
749 TREE_OPERAND (TREE_OPERAND (new_rhs, 0), 1) = index;
753 new_rhs = build4 (ARRAY_REF, TREE_TYPE (TREE_TYPE (TREE_TYPE (def_rhs))),
754 unshare_expr (TREE_OPERAND (def_rhs, 0)),
755 index, integer_zero_node, NULL_TREE);
756 new_rhs = build_fold_addr_expr (new_rhs);
757 if (!useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (use_stmt)),
758 TREE_TYPE (new_rhs)))
760 new_rhs = force_gimple_operand_gsi (use_stmt_gsi, new_rhs, true,
761 NULL_TREE, true, GSI_SAME_STMT);
762 new_rhs = fold_convert (TREE_TYPE (gimple_assign_lhs (use_stmt)),
766 gimple_assign_set_rhs_from_tree (use_stmt_gsi, new_rhs);
767 fold_stmt (use_stmt_gsi);
768 tidy_after_forward_propagate_addr (gsi_stmt (*use_stmt_gsi));
772 /* NAME is a SSA_NAME representing DEF_RHS which is of the form
773 ADDR_EXPR <whatever>.
775 Try to forward propagate the ADDR_EXPR into the use USE_STMT.
776 Often this will allow for removal of an ADDR_EXPR and INDIRECT_REF
777 node or for recovery of array indexing from pointer arithmetic.
779 Return true if the propagation was successful (the propagation can
780 be not totally successful, yet things may have been changed). */
783 forward_propagate_addr_expr_1 (tree name, tree def_rhs,
784 gimple_stmt_iterator *use_stmt_gsi,
787 tree lhs, rhs, rhs2, array_ref;
788 gimple use_stmt = gsi_stmt (*use_stmt_gsi);
789 enum tree_code rhs_code;
792 gcc_assert (TREE_CODE (def_rhs) == ADDR_EXPR);
794 lhs = gimple_assign_lhs (use_stmt);
795 rhs_code = gimple_assign_rhs_code (use_stmt);
796 rhs = gimple_assign_rhs1 (use_stmt);
798 /* Trivial cases. The use statement could be a trivial copy or a
799 useless conversion. Recurse to the uses of the lhs as copyprop does
800 not copy through different variant pointers and FRE does not catch
801 all useless conversions. Treat the case of a single-use name and
802 a conversion to def_rhs type separate, though. */
803 if (TREE_CODE (lhs) == SSA_NAME
804 && ((rhs_code == SSA_NAME && rhs == name)
805 || CONVERT_EXPR_CODE_P (rhs_code)))
807 /* Only recurse if we don't deal with a single use or we cannot
808 do the propagation to the current statement. In particular
809 we can end up with a conversion needed for a non-invariant
810 address which we cannot do in a single statement. */
812 || (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (def_rhs))
813 && (!is_gimple_min_invariant (def_rhs)
814 || (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
815 && POINTER_TYPE_P (TREE_TYPE (def_rhs))
816 && (TYPE_PRECISION (TREE_TYPE (lhs))
817 > TYPE_PRECISION (TREE_TYPE (def_rhs)))))))
818 return forward_propagate_addr_expr (lhs, def_rhs);
820 gimple_assign_set_rhs1 (use_stmt, unshare_expr (def_rhs));
821 if (useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (def_rhs)))
822 gimple_assign_set_rhs_code (use_stmt, TREE_CODE (def_rhs));
824 gimple_assign_set_rhs_code (use_stmt, NOP_EXPR);
828 /* Propagate through constant pointer adjustments. */
829 if (TREE_CODE (lhs) == SSA_NAME
830 && rhs_code == POINTER_PLUS_EXPR
832 && TREE_CODE (gimple_assign_rhs2 (use_stmt)) == INTEGER_CST)
835 /* As we come here with non-invariant addresses in def_rhs we need
836 to make sure we can build a valid constant offsetted address
837 for further propagation. Simply rely on fold building that
838 and check after the fact. */
839 new_def_rhs = fold_build2 (MEM_REF, TREE_TYPE (TREE_TYPE (rhs)),
841 fold_convert (ptr_type_node,
842 gimple_assign_rhs2 (use_stmt)));
843 if (TREE_CODE (new_def_rhs) == MEM_REF
844 && !is_gimple_mem_ref_addr (TREE_OPERAND (new_def_rhs, 0)))
846 new_def_rhs = build_fold_addr_expr_with_type (new_def_rhs,
849 /* Recurse. If we could propagate into all uses of lhs do not
850 bother to replace into the current use but just pretend we did. */
851 if (TREE_CODE (new_def_rhs) == ADDR_EXPR
852 && forward_propagate_addr_expr (lhs, new_def_rhs))
855 if (useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (new_def_rhs)))
856 gimple_assign_set_rhs_with_ops (use_stmt_gsi, TREE_CODE (new_def_rhs),
857 new_def_rhs, NULL_TREE);
858 else if (is_gimple_min_invariant (new_def_rhs))
859 gimple_assign_set_rhs_with_ops (use_stmt_gsi, NOP_EXPR,
860 new_def_rhs, NULL_TREE);
863 gcc_assert (gsi_stmt (*use_stmt_gsi) == use_stmt);
864 update_stmt (use_stmt);
868 /* Now strip away any outer COMPONENT_REF/ARRAY_REF nodes from the LHS.
869 ADDR_EXPR will not appear on the LHS. */
870 lhs = gimple_assign_lhs (use_stmt);
871 while (handled_component_p (lhs))
872 lhs = TREE_OPERAND (lhs, 0);
874 /* Now see if the LHS node is a MEM_REF using NAME. If so,
875 propagate the ADDR_EXPR into the use of NAME and fold the result. */
876 if (TREE_CODE (lhs) == MEM_REF
877 && TREE_OPERAND (lhs, 0) == name)
880 HOST_WIDE_INT def_rhs_offset;
881 /* If the address is invariant we can always fold it. */
882 if ((def_rhs_base = get_addr_base_and_unit_offset (TREE_OPERAND (def_rhs, 0),
885 double_int off = mem_ref_offset (lhs);
887 off = double_int_add (off,
888 shwi_to_double_int (def_rhs_offset));
889 if (TREE_CODE (def_rhs_base) == MEM_REF)
891 off = double_int_add (off, mem_ref_offset (def_rhs_base));
892 new_ptr = TREE_OPERAND (def_rhs_base, 0);
895 new_ptr = build_fold_addr_expr (def_rhs_base);
896 TREE_OPERAND (lhs, 0) = new_ptr;
897 TREE_OPERAND (lhs, 1)
898 = double_int_to_tree (TREE_TYPE (TREE_OPERAND (lhs, 1)), off);
899 tidy_after_forward_propagate_addr (use_stmt);
900 /* Continue propagating into the RHS if this was not the only use. */
904 /* If the LHS is a plain dereference and the value type is the same as
905 that of the pointed-to type of the address we can put the
906 dereferenced address on the LHS preserving the original alias-type. */
907 else if (gimple_assign_lhs (use_stmt) == lhs
908 && useless_type_conversion_p
909 (TREE_TYPE (TREE_OPERAND (def_rhs, 0)),
910 TREE_TYPE (gimple_assign_rhs1 (use_stmt))))
912 tree *def_rhs_basep = &TREE_OPERAND (def_rhs, 0);
913 tree new_offset, new_base, saved;
914 while (handled_component_p (*def_rhs_basep))
915 def_rhs_basep = &TREE_OPERAND (*def_rhs_basep, 0);
916 saved = *def_rhs_basep;
917 if (TREE_CODE (*def_rhs_basep) == MEM_REF)
919 new_base = TREE_OPERAND (*def_rhs_basep, 0);
921 = int_const_binop (PLUS_EXPR, TREE_OPERAND (lhs, 1),
922 TREE_OPERAND (*def_rhs_basep, 1));
926 new_base = build_fold_addr_expr (*def_rhs_basep);
927 new_offset = TREE_OPERAND (lhs, 1);
929 *def_rhs_basep = build2 (MEM_REF, TREE_TYPE (*def_rhs_basep),
930 new_base, new_offset);
931 TREE_THIS_VOLATILE (*def_rhs_basep) = TREE_THIS_VOLATILE (lhs);
932 TREE_THIS_NOTRAP (*def_rhs_basep) = TREE_THIS_NOTRAP (lhs);
933 gimple_assign_set_lhs (use_stmt,
934 unshare_expr (TREE_OPERAND (def_rhs, 0)));
935 *def_rhs_basep = saved;
936 tidy_after_forward_propagate_addr (use_stmt);
937 /* Continue propagating into the RHS if this was not the
943 /* We can have a struct assignment dereferencing our name twice.
944 Note that we didn't propagate into the lhs to not falsely
945 claim we did when propagating into the rhs. */
949 /* Strip away any outer COMPONENT_REF, ARRAY_REF or ADDR_EXPR
950 nodes from the RHS. */
951 rhs = gimple_assign_rhs1 (use_stmt);
952 if (TREE_CODE (rhs) == ADDR_EXPR)
953 rhs = TREE_OPERAND (rhs, 0);
954 while (handled_component_p (rhs))
955 rhs = TREE_OPERAND (rhs, 0);
957 /* Now see if the RHS node is a MEM_REF using NAME. If so,
958 propagate the ADDR_EXPR into the use of NAME and fold the result. */
959 if (TREE_CODE (rhs) == MEM_REF
960 && TREE_OPERAND (rhs, 0) == name)
963 HOST_WIDE_INT def_rhs_offset;
964 if ((def_rhs_base = get_addr_base_and_unit_offset (TREE_OPERAND (def_rhs, 0),
967 double_int off = mem_ref_offset (rhs);
969 off = double_int_add (off,
970 shwi_to_double_int (def_rhs_offset));
971 if (TREE_CODE (def_rhs_base) == MEM_REF)
973 off = double_int_add (off, mem_ref_offset (def_rhs_base));
974 new_ptr = TREE_OPERAND (def_rhs_base, 0);
977 new_ptr = build_fold_addr_expr (def_rhs_base);
978 TREE_OPERAND (rhs, 0) = new_ptr;
979 TREE_OPERAND (rhs, 1)
980 = double_int_to_tree (TREE_TYPE (TREE_OPERAND (rhs, 1)), off);
981 fold_stmt_inplace (use_stmt_gsi);
982 tidy_after_forward_propagate_addr (use_stmt);
985 /* If the RHS is a plain dereference and the value type is the same as
986 that of the pointed-to type of the address we can put the
987 dereferenced address on the RHS preserving the original alias-type. */
988 else if (gimple_assign_rhs1 (use_stmt) == rhs
989 && useless_type_conversion_p
990 (TREE_TYPE (gimple_assign_lhs (use_stmt)),
991 TREE_TYPE (TREE_OPERAND (def_rhs, 0))))
993 tree *def_rhs_basep = &TREE_OPERAND (def_rhs, 0);
994 tree new_offset, new_base, saved;
995 while (handled_component_p (*def_rhs_basep))
996 def_rhs_basep = &TREE_OPERAND (*def_rhs_basep, 0);
997 saved = *def_rhs_basep;
998 if (TREE_CODE (*def_rhs_basep) == MEM_REF)
1000 new_base = TREE_OPERAND (*def_rhs_basep, 0);
1002 = int_const_binop (PLUS_EXPR, TREE_OPERAND (rhs, 1),
1003 TREE_OPERAND (*def_rhs_basep, 1));
1007 new_base = build_fold_addr_expr (*def_rhs_basep);
1008 new_offset = TREE_OPERAND (rhs, 1);
1010 *def_rhs_basep = build2 (MEM_REF, TREE_TYPE (*def_rhs_basep),
1011 new_base, new_offset);
1012 TREE_THIS_VOLATILE (*def_rhs_basep) = TREE_THIS_VOLATILE (rhs);
1013 TREE_THIS_NOTRAP (*def_rhs_basep) = TREE_THIS_NOTRAP (rhs);
1014 gimple_assign_set_rhs1 (use_stmt,
1015 unshare_expr (TREE_OPERAND (def_rhs, 0)));
1016 *def_rhs_basep = saved;
1017 fold_stmt_inplace (use_stmt_gsi);
1018 tidy_after_forward_propagate_addr (use_stmt);
1023 /* If the use of the ADDR_EXPR is not a POINTER_PLUS_EXPR, there
1024 is nothing to do. */
1025 if (gimple_assign_rhs_code (use_stmt) != POINTER_PLUS_EXPR
1026 || gimple_assign_rhs1 (use_stmt) != name)
1029 /* The remaining cases are all for turning pointer arithmetic into
1030 array indexing. They only apply when we have the address of
1031 element zero in an array. If that is not the case then there
1032 is nothing to do. */
1033 array_ref = TREE_OPERAND (def_rhs, 0);
1034 if ((TREE_CODE (array_ref) != ARRAY_REF
1035 || TREE_CODE (TREE_TYPE (TREE_OPERAND (array_ref, 0))) != ARRAY_TYPE
1036 || TREE_CODE (TREE_OPERAND (array_ref, 1)) != INTEGER_CST)
1037 && TREE_CODE (TREE_TYPE (array_ref)) != ARRAY_TYPE)
1040 rhs2 = gimple_assign_rhs2 (use_stmt);
1041 /* Optimize &x[C1] p+ C2 to &x p+ C3 with C3 = C1 * element_size + C2. */
1042 if (TREE_CODE (rhs2) == INTEGER_CST)
1044 tree new_rhs = build1_loc (gimple_location (use_stmt),
1045 ADDR_EXPR, TREE_TYPE (def_rhs),
1046 fold_build2 (MEM_REF,
1047 TREE_TYPE (TREE_TYPE (def_rhs)),
1048 unshare_expr (def_rhs),
1049 fold_convert (ptr_type_node,
1051 gimple_assign_set_rhs_from_tree (use_stmt_gsi, new_rhs);
1052 use_stmt = gsi_stmt (*use_stmt_gsi);
1053 update_stmt (use_stmt);
1054 tidy_after_forward_propagate_addr (use_stmt);
1058 /* Try to optimize &x[0] p+ OFFSET where OFFSET is defined by
1059 converting a multiplication of an index by the size of the
1060 array elements, then the result is converted into the proper
1061 type for the arithmetic. */
1062 if (TREE_CODE (rhs2) == SSA_NAME
1063 && (TREE_CODE (array_ref) != ARRAY_REF
1064 || integer_zerop (TREE_OPERAND (array_ref, 1)))
1065 && useless_type_conversion_p (TREE_TYPE (name), TREE_TYPE (def_rhs))
1066 /* Avoid problems with IVopts creating PLUS_EXPRs with a
1067 different type than their operands. */
1068 && useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (def_rhs)))
1069 return forward_propagate_addr_into_variable_array_index (rhs2, def_rhs,
1074 /* STMT is a statement of the form SSA_NAME = ADDR_EXPR <whatever>.
1076 Try to forward propagate the ADDR_EXPR into all uses of the SSA_NAME.
1077 Often this will allow for removal of an ADDR_EXPR and INDIRECT_REF
1078 node or for recovery of array indexing from pointer arithmetic.
1079 Returns true, if all uses have been propagated into. */
1082 forward_propagate_addr_expr (tree name, tree rhs)
1084 int stmt_loop_depth = gimple_bb (SSA_NAME_DEF_STMT (name))->loop_depth;
1085 imm_use_iterator iter;
1088 bool single_use_p = has_single_use (name);
1090 FOR_EACH_IMM_USE_STMT (use_stmt, iter, name)
1095 /* If the use is not in a simple assignment statement, then
1096 there is nothing we can do. */
1097 if (gimple_code (use_stmt) != GIMPLE_ASSIGN)
1099 if (!is_gimple_debug (use_stmt))
1104 /* If the use is in a deeper loop nest, then we do not want
1105 to propagate non-invariant ADDR_EXPRs into the loop as that
1106 is likely adding expression evaluations into the loop. */
1107 if (gimple_bb (use_stmt)->loop_depth > stmt_loop_depth
1108 && !is_gimple_min_invariant (rhs))
1115 gimple_stmt_iterator gsi = gsi_for_stmt (use_stmt);
1116 result = forward_propagate_addr_expr_1 (name, rhs, &gsi,
1118 /* If the use has moved to a different statement adjust
1119 the update machinery for the old statement too. */
1120 if (use_stmt != gsi_stmt (gsi))
1122 update_stmt (use_stmt);
1123 use_stmt = gsi_stmt (gsi);
1126 update_stmt (use_stmt);
1130 /* Remove intermediate now unused copy and conversion chains. */
1131 use_rhs = gimple_assign_rhs1 (use_stmt);
1133 && TREE_CODE (gimple_assign_lhs (use_stmt)) == SSA_NAME
1134 && TREE_CODE (use_rhs) == SSA_NAME
1135 && has_zero_uses (gimple_assign_lhs (use_stmt)))
1137 gimple_stmt_iterator gsi = gsi_for_stmt (use_stmt);
1138 release_defs (use_stmt);
1139 gsi_remove (&gsi, true);
1143 return all && has_zero_uses (name);
1147 /* Forward propagate the comparison defined in STMT like
1148 cond_1 = x CMP y to uses of the form
1152 Returns true if stmt is now unused. */
1155 forward_propagate_comparison (gimple stmt)
1157 tree name = gimple_assign_lhs (stmt);
1159 tree tmp = NULL_TREE;
1160 gimple_stmt_iterator gsi;
1161 enum tree_code code;
1164 /* Don't propagate ssa names that occur in abnormal phis. */
1165 if ((TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
1166 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_assign_rhs1 (stmt)))
1167 || (TREE_CODE (gimple_assign_rhs2 (stmt)) == SSA_NAME
1168 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_assign_rhs2 (stmt))))
1171 /* Do not un-cse comparisons. But propagate through copies. */
1172 use_stmt = get_prop_dest_stmt (name, &name);
1174 || !is_gimple_assign (use_stmt))
1177 code = gimple_assign_rhs_code (use_stmt);
1178 lhs = gimple_assign_lhs (use_stmt);
1179 if (!INTEGRAL_TYPE_P (TREE_TYPE (lhs)))
1182 /* We can propagate the condition into a statement that
1183 computes the logical negation of the comparison result. */
1184 if ((code == BIT_NOT_EXPR
1185 && TYPE_PRECISION (TREE_TYPE (lhs)) == 1)
1186 || (code == BIT_XOR_EXPR
1187 && integer_onep (gimple_assign_rhs2 (use_stmt))))
1189 tree type = TREE_TYPE (gimple_assign_rhs1 (stmt));
1190 bool nans = HONOR_NANS (TYPE_MODE (type));
1191 enum tree_code inv_code;
1192 inv_code = invert_tree_comparison (gimple_assign_rhs_code (stmt), nans);
1193 if (inv_code == ERROR_MARK)
1196 tmp = build2 (inv_code, TREE_TYPE (lhs), gimple_assign_rhs1 (stmt),
1197 gimple_assign_rhs2 (stmt));
1202 gsi = gsi_for_stmt (use_stmt);
1203 gimple_assign_set_rhs_from_tree (&gsi, unshare_expr (tmp));
1204 use_stmt = gsi_stmt (gsi);
1205 update_stmt (use_stmt);
1207 if (dump_file && (dump_flags & TDF_DETAILS))
1209 fprintf (dump_file, " Replaced '");
1210 print_gimple_expr (dump_file, stmt, 0, dump_flags);
1211 fprintf (dump_file, "' with '");
1212 print_gimple_expr (dump_file, use_stmt, 0, dump_flags);
1213 fprintf (dump_file, "'\n");
1216 /* Remove defining statements. */
1217 return remove_prop_source_from_use (name);
1221 /* If we have lhs = ~x (STMT), look and see if earlier we had x = ~y.
1222 If so, we can change STMT into lhs = y which can later be copy
1223 propagated. Similarly for negation.
1225 This could trivially be formulated as a forward propagation
1226 to immediate uses. However, we already had an implementation
1227 from DOM which used backward propagation via the use-def links.
1229 It turns out that backward propagation is actually faster as
1230 there's less work to do for each NOT/NEG expression we find.
1231 Backwards propagation needs to look at the statement in a single
1232 backlink. Forward propagation needs to look at potentially more
1233 than one forward link.
1235 Returns true when the statement was changed. */
1238 simplify_not_neg_expr (gimple_stmt_iterator *gsi_p)
1240 gimple stmt = gsi_stmt (*gsi_p);
1241 tree rhs = gimple_assign_rhs1 (stmt);
1242 gimple rhs_def_stmt = SSA_NAME_DEF_STMT (rhs);
1244 /* See if the RHS_DEF_STMT has the same form as our statement. */
1245 if (is_gimple_assign (rhs_def_stmt)
1246 && gimple_assign_rhs_code (rhs_def_stmt) == gimple_assign_rhs_code (stmt))
1248 tree rhs_def_operand = gimple_assign_rhs1 (rhs_def_stmt);
1250 /* Verify that RHS_DEF_OPERAND is a suitable SSA_NAME. */
1251 if (TREE_CODE (rhs_def_operand) == SSA_NAME
1252 && ! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs_def_operand))
1254 gimple_assign_set_rhs_from_tree (gsi_p, rhs_def_operand);
1255 stmt = gsi_stmt (*gsi_p);
1264 /* STMT is a SWITCH_EXPR for which we attempt to find equivalent forms of
1265 the condition which we may be able to optimize better. */
1268 simplify_gimple_switch (gimple stmt)
1270 tree cond = gimple_switch_index (stmt);
1274 /* The optimization that we really care about is removing unnecessary
1275 casts. That will let us do much better in propagating the inferred
1276 constant at the switch target. */
1277 if (TREE_CODE (cond) == SSA_NAME)
1279 def_stmt = SSA_NAME_DEF_STMT (cond);
1280 if (is_gimple_assign (def_stmt))
1282 if (gimple_assign_rhs_code (def_stmt) == NOP_EXPR)
1287 def = gimple_assign_rhs1 (def_stmt);
1289 /* ??? Why was Jeff testing this? We are gimple... */
1290 gcc_checking_assert (is_gimple_val (def));
1292 to = TREE_TYPE (cond);
1293 ti = TREE_TYPE (def);
1295 /* If we have an extension that preserves value, then we
1296 can copy the source value into the switch. */
1298 need_precision = TYPE_PRECISION (ti);
1300 if (! INTEGRAL_TYPE_P (ti))
1302 else if (TYPE_UNSIGNED (to) && !TYPE_UNSIGNED (ti))
1304 else if (!TYPE_UNSIGNED (to) && TYPE_UNSIGNED (ti))
1305 need_precision += 1;
1306 if (TYPE_PRECISION (to) < need_precision)
1311 gimple_switch_set_index (stmt, def);
1322 /* For pointers p2 and p1 return p2 - p1 if the
1323 difference is known and constant, otherwise return NULL. */
1326 constant_pointer_difference (tree p1, tree p2)
1329 #define CPD_ITERATIONS 5
1330 tree exps[2][CPD_ITERATIONS];
1331 tree offs[2][CPD_ITERATIONS];
1334 for (i = 0; i < 2; i++)
1336 tree p = i ? p1 : p2;
1337 tree off = size_zero_node;
1339 enum tree_code code;
1341 /* For each of p1 and p2 we need to iterate at least
1342 twice, to handle ADDR_EXPR directly in p1/p2,
1343 SSA_NAME with ADDR_EXPR or POINTER_PLUS_EXPR etc.
1344 on definition's stmt RHS. Iterate a few extra times. */
1348 if (!POINTER_TYPE_P (TREE_TYPE (p)))
1350 if (TREE_CODE (p) == ADDR_EXPR)
1352 tree q = TREE_OPERAND (p, 0);
1353 HOST_WIDE_INT offset;
1354 tree base = get_addr_base_and_unit_offset (q, &offset);
1359 off = size_binop (PLUS_EXPR, off, size_int (offset));
1361 if (TREE_CODE (q) == MEM_REF
1362 && TREE_CODE (TREE_OPERAND (q, 0)) == SSA_NAME)
1364 p = TREE_OPERAND (q, 0);
1365 off = size_binop (PLUS_EXPR, off,
1366 double_int_to_tree (sizetype,
1367 mem_ref_offset (q)));
1376 if (TREE_CODE (p) != SSA_NAME)
1380 if (j == CPD_ITERATIONS)
1382 stmt = SSA_NAME_DEF_STMT (p);
1383 if (!is_gimple_assign (stmt) || gimple_assign_lhs (stmt) != p)
1385 code = gimple_assign_rhs_code (stmt);
1386 if (code == POINTER_PLUS_EXPR)
1388 if (TREE_CODE (gimple_assign_rhs2 (stmt)) != INTEGER_CST)
1390 off = size_binop (PLUS_EXPR, off, gimple_assign_rhs2 (stmt));
1391 p = gimple_assign_rhs1 (stmt);
1393 else if (code == ADDR_EXPR || code == NOP_EXPR)
1394 p = gimple_assign_rhs1 (stmt);
1402 for (i = 0; i < cnt[0]; i++)
1403 for (j = 0; j < cnt[1]; j++)
1404 if (exps[0][i] == exps[1][j])
1405 return size_binop (MINUS_EXPR, offs[0][i], offs[1][j]);
1410 /* *GSI_P is a GIMPLE_CALL to a builtin function.
1412 memcpy (p, "abcd", 4);
1413 memset (p + 4, ' ', 3);
1415 memcpy (p, "abcd ", 7);
1416 call if the latter can be stored by pieces during expansion. */
1419 simplify_builtin_call (gimple_stmt_iterator *gsi_p, tree callee2)
1421 gimple stmt1, stmt2 = gsi_stmt (*gsi_p);
1422 tree vuse = gimple_vuse (stmt2);
1425 stmt1 = SSA_NAME_DEF_STMT (vuse);
1427 switch (DECL_FUNCTION_CODE (callee2))
1429 case BUILT_IN_MEMSET:
1430 if (gimple_call_num_args (stmt2) != 3
1431 || gimple_call_lhs (stmt2)
1433 || BITS_PER_UNIT != 8)
1438 tree ptr1, src1, str1, off1, len1, lhs1;
1439 tree ptr2 = gimple_call_arg (stmt2, 0);
1440 tree val2 = gimple_call_arg (stmt2, 1);
1441 tree len2 = gimple_call_arg (stmt2, 2);
1442 tree diff, vdef, new_str_cst;
1444 unsigned int ptr1_align;
1445 unsigned HOST_WIDE_INT src_len;
1447 use_operand_p use_p;
1449 if (!host_integerp (val2, 0)
1450 || !host_integerp (len2, 1))
1452 if (is_gimple_call (stmt1))
1454 /* If first stmt is a call, it needs to be memcpy
1455 or mempcpy, with string literal as second argument and
1457 callee1 = gimple_call_fndecl (stmt1);
1458 if (callee1 == NULL_TREE
1459 || DECL_BUILT_IN_CLASS (callee1) != BUILT_IN_NORMAL
1460 || gimple_call_num_args (stmt1) != 3)
1462 if (DECL_FUNCTION_CODE (callee1) != BUILT_IN_MEMCPY
1463 && DECL_FUNCTION_CODE (callee1) != BUILT_IN_MEMPCPY)
1465 ptr1 = gimple_call_arg (stmt1, 0);
1466 src1 = gimple_call_arg (stmt1, 1);
1467 len1 = gimple_call_arg (stmt1, 2);
1468 lhs1 = gimple_call_lhs (stmt1);
1469 if (!host_integerp (len1, 1))
1471 str1 = string_constant (src1, &off1);
1472 if (str1 == NULL_TREE)
1474 if (!host_integerp (off1, 1)
1475 || compare_tree_int (off1, TREE_STRING_LENGTH (str1) - 1) > 0
1476 || compare_tree_int (len1, TREE_STRING_LENGTH (str1)
1477 - tree_low_cst (off1, 1)) > 0
1478 || TREE_CODE (TREE_TYPE (str1)) != ARRAY_TYPE
1479 || TYPE_MODE (TREE_TYPE (TREE_TYPE (str1)))
1480 != TYPE_MODE (char_type_node))
1483 else if (gimple_assign_single_p (stmt1))
1485 /* Otherwise look for length 1 memcpy optimized into
1487 ptr1 = gimple_assign_lhs (stmt1);
1488 src1 = gimple_assign_rhs1 (stmt1);
1489 if (TREE_CODE (ptr1) != MEM_REF
1490 || TYPE_MODE (TREE_TYPE (ptr1)) != TYPE_MODE (char_type_node)
1491 || !host_integerp (src1, 0))
1493 ptr1 = build_fold_addr_expr (ptr1);
1494 callee1 = NULL_TREE;
1495 len1 = size_one_node;
1497 off1 = size_zero_node;
1503 diff = constant_pointer_difference (ptr1, ptr2);
1504 if (diff == NULL && lhs1 != NULL)
1506 diff = constant_pointer_difference (lhs1, ptr2);
1507 if (DECL_FUNCTION_CODE (callee1) == BUILT_IN_MEMPCPY
1509 diff = size_binop (PLUS_EXPR, diff,
1510 fold_convert (sizetype, len1));
1512 /* If the difference between the second and first destination pointer
1513 is not constant, or is bigger than memcpy length, bail out. */
1515 || !host_integerp (diff, 1)
1516 || tree_int_cst_lt (len1, diff))
1519 /* Use maximum of difference plus memset length and memcpy length
1520 as the new memcpy length, if it is too big, bail out. */
1521 src_len = tree_low_cst (diff, 1);
1522 src_len += tree_low_cst (len2, 1);
1523 if (src_len < (unsigned HOST_WIDE_INT) tree_low_cst (len1, 1))
1524 src_len = tree_low_cst (len1, 1);
1528 /* If mempcpy value is used elsewhere, bail out, as mempcpy
1529 with bigger length will return different result. */
1530 if (lhs1 != NULL_TREE
1531 && DECL_FUNCTION_CODE (callee1) == BUILT_IN_MEMPCPY
1532 && (TREE_CODE (lhs1) != SSA_NAME
1533 || !single_imm_use (lhs1, &use_p, &use_stmt)
1534 || use_stmt != stmt2))
1537 /* If anything reads memory in between memcpy and memset
1538 call, the modified memcpy call might change it. */
1539 vdef = gimple_vdef (stmt1);
1541 && (!single_imm_use (vdef, &use_p, &use_stmt)
1542 || use_stmt != stmt2))
1545 ptr1_align = get_pointer_alignment (ptr1);
1546 /* Construct the new source string literal. */
1547 src_buf = XALLOCAVEC (char, src_len + 1);
1550 TREE_STRING_POINTER (str1) + tree_low_cst (off1, 1),
1551 tree_low_cst (len1, 1));
1553 src_buf[0] = tree_low_cst (src1, 0);
1554 memset (src_buf + tree_low_cst (diff, 1),
1555 tree_low_cst (val2, 1), tree_low_cst (len2, 1));
1556 src_buf[src_len] = '\0';
1557 /* Neither builtin_strncpy_read_str nor builtin_memcpy_read_str
1558 handle embedded '\0's. */
1559 if (strlen (src_buf) != src_len)
1561 rtl_profile_for_bb (gimple_bb (stmt2));
1562 /* If the new memcpy wouldn't be emitted by storing the literal
1563 by pieces, this optimization might enlarge .rodata too much,
1564 as commonly used string literals couldn't be shared any
1566 if (!can_store_by_pieces (src_len,
1567 builtin_strncpy_read_str,
1568 src_buf, ptr1_align, false))
1571 new_str_cst = build_string_literal (src_len, src_buf);
1574 /* If STMT1 is a mem{,p}cpy call, adjust it and remove
1576 if (lhs1 && DECL_FUNCTION_CODE (callee1) == BUILT_IN_MEMPCPY)
1577 gimple_call_set_lhs (stmt1, NULL_TREE);
1578 gimple_call_set_arg (stmt1, 1, new_str_cst);
1579 gimple_call_set_arg (stmt1, 2,
1580 build_int_cst (TREE_TYPE (len1), src_len));
1581 update_stmt (stmt1);
1582 unlink_stmt_vdef (stmt2);
1583 gsi_remove (gsi_p, true);
1584 release_defs (stmt2);
1585 if (lhs1 && DECL_FUNCTION_CODE (callee1) == BUILT_IN_MEMPCPY)
1586 release_ssa_name (lhs1);
1591 /* Otherwise, if STMT1 is length 1 memcpy optimized into
1592 assignment, remove STMT1 and change memset call into
1594 gimple_stmt_iterator gsi = gsi_for_stmt (stmt1);
1596 if (!is_gimple_val (ptr1))
1597 ptr1 = force_gimple_operand_gsi (gsi_p, ptr1, true, NULL_TREE,
1598 true, GSI_SAME_STMT);
1599 gimple_call_set_fndecl (stmt2, built_in_decls [BUILT_IN_MEMCPY]);
1600 gimple_call_set_arg (stmt2, 0, ptr1);
1601 gimple_call_set_arg (stmt2, 1, new_str_cst);
1602 gimple_call_set_arg (stmt2, 2,
1603 build_int_cst (TREE_TYPE (len2), src_len));
1604 unlink_stmt_vdef (stmt1);
1605 gsi_remove (&gsi, true);
1606 release_defs (stmt1);
1607 update_stmt (stmt2);
1618 /* Checks if expression has type of one-bit precision, or is a known
1619 truth-valued expression. */
1621 truth_valued_ssa_name (tree name)
1624 tree type = TREE_TYPE (name);
1626 if (!INTEGRAL_TYPE_P (type))
1628 /* Don't check here for BOOLEAN_TYPE as the precision isn't
1629 necessarily one and so ~X is not equal to !X. */
1630 if (TYPE_PRECISION (type) == 1)
1632 def = SSA_NAME_DEF_STMT (name);
1633 if (is_gimple_assign (def))
1634 return truth_value_p (gimple_assign_rhs_code (def));
1638 /* Helper routine for simplify_bitwise_binary_1 function.
1639 Return for the SSA name NAME the expression X if it mets condition
1640 NAME = !X. Otherwise return NULL_TREE.
1641 Detected patterns for NAME = !X are:
1642 !X and X == 0 for X with integral type.
1643 X ^ 1, X != 1,or ~X for X with integral type with precision of one. */
1645 lookup_logical_inverted_value (tree name)
1648 enum tree_code code;
1651 /* If name has none-intergal type, or isn't a SSA_NAME, then
1653 if (TREE_CODE (name) != SSA_NAME
1654 || !INTEGRAL_TYPE_P (TREE_TYPE (name)))
1656 def = SSA_NAME_DEF_STMT (name);
1657 if (!is_gimple_assign (def))
1660 code = gimple_assign_rhs_code (def);
1661 op1 = gimple_assign_rhs1 (def);
1664 /* Get for EQ_EXPR or BIT_XOR_EXPR operation the second operand.
1665 If CODE isn't an EQ_EXPR, BIT_XOR_EXPR, or BIT_NOT_EXPR, then return. */
1666 if (code == EQ_EXPR || code == NE_EXPR
1667 || code == BIT_XOR_EXPR)
1668 op2 = gimple_assign_rhs2 (def);
1673 if (truth_valued_ssa_name (name))
1677 /* Check if we have X == 0 and X has an integral type. */
1678 if (!INTEGRAL_TYPE_P (TREE_TYPE (op1)))
1680 if (integer_zerop (op2))
1684 /* Check if we have X != 1 and X is a truth-valued. */
1685 if (!INTEGRAL_TYPE_P (TREE_TYPE (op1)))
1687 if (integer_onep (op2) && truth_valued_ssa_name (op1))
1691 /* Check if we have X ^ 1 and X is truth valued. */
1692 if (integer_onep (op2) && truth_valued_ssa_name (op1))
1702 /* Optimize ARG1 CODE ARG2 to a constant for bitwise binary
1703 operations CODE, if one operand has the logically inverted
1704 value of the other. */
1706 simplify_bitwise_binary_1 (enum tree_code code, tree type,
1707 tree arg1, tree arg2)
1711 /* If CODE isn't a bitwise binary operation, return NULL_TREE. */
1712 if (code != BIT_AND_EXPR && code != BIT_IOR_EXPR
1713 && code != BIT_XOR_EXPR)
1716 /* First check if operands ARG1 and ARG2 are equal. If so
1717 return NULL_TREE as this optimization is handled fold_stmt. */
1720 /* See if we have in arguments logical-not patterns. */
1721 if (((anot = lookup_logical_inverted_value (arg1)) == NULL_TREE
1723 && ((anot = lookup_logical_inverted_value (arg2)) == NULL_TREE
1728 if (code == BIT_AND_EXPR)
1729 return fold_convert (type, integer_zero_node);
1730 /* X | !X -> 1 and X ^ !X -> 1, if X is truth-valued. */
1731 if (truth_valued_ssa_name (anot))
1732 return fold_convert (type, integer_one_node);
1734 /* ??? Otherwise result is (X != 0 ? X : 1). not handled. */
1738 /* Simplify bitwise binary operations.
1739 Return true if a transformation applied, otherwise return false. */
1742 simplify_bitwise_binary (gimple_stmt_iterator *gsi)
1744 gimple stmt = gsi_stmt (*gsi);
1745 tree arg1 = gimple_assign_rhs1 (stmt);
1746 tree arg2 = gimple_assign_rhs2 (stmt);
1747 enum tree_code code = gimple_assign_rhs_code (stmt);
1749 gimple def1 = NULL, def2 = NULL;
1750 tree def1_arg1, def2_arg1;
1751 enum tree_code def1_code, def2_code;
1753 def1_code = TREE_CODE (arg1);
1755 if (TREE_CODE (arg1) == SSA_NAME)
1757 def1 = SSA_NAME_DEF_STMT (arg1);
1758 if (is_gimple_assign (def1))
1760 def1_code = gimple_assign_rhs_code (def1);
1761 def1_arg1 = gimple_assign_rhs1 (def1);
1765 def2_code = TREE_CODE (arg2);
1767 if (TREE_CODE (arg2) == SSA_NAME)
1769 def2 = SSA_NAME_DEF_STMT (arg2);
1770 if (is_gimple_assign (def2))
1772 def2_code = gimple_assign_rhs_code (def2);
1773 def2_arg1 = gimple_assign_rhs1 (def2);
1777 /* Try to fold (type) X op CST -> (type) (X op ((type-x) CST)). */
1778 if (TREE_CODE (arg2) == INTEGER_CST
1779 && CONVERT_EXPR_CODE_P (def1_code)
1780 && INTEGRAL_TYPE_P (TREE_TYPE (def1_arg1))
1781 && int_fits_type_p (arg2, TREE_TYPE (def1_arg1)))
1784 tree tem = create_tmp_reg (TREE_TYPE (def1_arg1), NULL);
1786 gimple_build_assign_with_ops (code, tem, def1_arg1,
1787 fold_convert_loc (gimple_location (stmt),
1788 TREE_TYPE (def1_arg1),
1790 tem = make_ssa_name (tem, newop);
1791 gimple_assign_set_lhs (newop, tem);
1792 gimple_set_location (newop, gimple_location (stmt));
1793 gsi_insert_before (gsi, newop, GSI_SAME_STMT);
1794 gimple_assign_set_rhs_with_ops_1 (gsi, NOP_EXPR,
1795 tem, NULL_TREE, NULL_TREE);
1796 update_stmt (gsi_stmt (*gsi));
1800 /* For bitwise binary operations apply operand conversions to the
1801 binary operation result instead of to the operands. This allows
1802 to combine successive conversions and bitwise binary operations. */
1803 if (CONVERT_EXPR_CODE_P (def1_code)
1804 && CONVERT_EXPR_CODE_P (def2_code)
1805 && types_compatible_p (TREE_TYPE (def1_arg1), TREE_TYPE (def2_arg1))
1806 /* Make sure that the conversion widens the operands, or has same
1807 precision, or that it changes the operation to a bitfield
1809 && ((TYPE_PRECISION (TREE_TYPE (def1_arg1))
1810 <= TYPE_PRECISION (TREE_TYPE (arg1)))
1811 || (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (arg1)))
1813 || (TYPE_PRECISION (TREE_TYPE (arg1))
1814 != GET_MODE_PRECISION (TYPE_MODE (TREE_TYPE (arg1))))))
1817 tree tem = create_tmp_reg (TREE_TYPE (def1_arg1),
1819 newop = gimple_build_assign_with_ops (code, tem, def1_arg1, def2_arg1);
1820 tem = make_ssa_name (tem, newop);
1821 gimple_assign_set_lhs (newop, tem);
1822 gimple_set_location (newop, gimple_location (stmt));
1823 gsi_insert_before (gsi, newop, GSI_SAME_STMT);
1824 gimple_assign_set_rhs_with_ops_1 (gsi, NOP_EXPR,
1825 tem, NULL_TREE, NULL_TREE);
1826 update_stmt (gsi_stmt (*gsi));
1830 /* (a | CST1) & CST2 -> (a & CST2) | (CST1 & CST2). */
1831 if (code == BIT_AND_EXPR
1832 && def1_code == BIT_IOR_EXPR
1833 && TREE_CODE (arg2) == INTEGER_CST
1834 && TREE_CODE (gimple_assign_rhs2 (def1)) == INTEGER_CST)
1836 tree cst = fold_build2 (BIT_AND_EXPR, TREE_TYPE (arg2),
1837 arg2, gimple_assign_rhs2 (def1));
1840 if (integer_zerop (cst))
1842 gimple_assign_set_rhs1 (stmt, def1_arg1);
1846 tem = create_tmp_reg (TREE_TYPE (arg2), NULL);
1847 newop = gimple_build_assign_with_ops (BIT_AND_EXPR,
1848 tem, def1_arg1, arg2);
1849 tem = make_ssa_name (tem, newop);
1850 gimple_assign_set_lhs (newop, tem);
1851 gimple_set_location (newop, gimple_location (stmt));
1852 /* Make sure to re-process the new stmt as it's walking upwards. */
1853 gsi_insert_before (gsi, newop, GSI_NEW_STMT);
1854 gimple_assign_set_rhs1 (stmt, tem);
1855 gimple_assign_set_rhs2 (stmt, cst);
1856 gimple_assign_set_rhs_code (stmt, BIT_IOR_EXPR);
1861 /* Combine successive equal operations with constants. */
1862 if ((code == BIT_AND_EXPR
1863 || code == BIT_IOR_EXPR
1864 || code == BIT_XOR_EXPR)
1865 && def1_code == code
1866 && TREE_CODE (arg2) == INTEGER_CST
1867 && TREE_CODE (gimple_assign_rhs2 (def1)) == INTEGER_CST)
1869 tree cst = fold_build2 (code, TREE_TYPE (arg2),
1870 arg2, gimple_assign_rhs2 (def1));
1871 gimple_assign_set_rhs1 (stmt, def1_arg1);
1872 gimple_assign_set_rhs2 (stmt, cst);
1877 /* Canonicalize X ^ ~0 to ~X. */
1878 if (code == BIT_XOR_EXPR
1879 && TREE_CODE (arg2) == INTEGER_CST
1880 && integer_all_onesp (arg2))
1882 gimple_assign_set_rhs_with_ops (gsi, BIT_NOT_EXPR, arg1, NULL_TREE);
1883 gcc_assert (gsi_stmt (*gsi) == stmt);
1888 /* Try simple folding for X op !X, and X op X. */
1889 res = simplify_bitwise_binary_1 (code, TREE_TYPE (arg1), arg1, arg2);
1890 if (res != NULL_TREE)
1892 gimple_assign_set_rhs_from_tree (gsi, res);
1893 update_stmt (gsi_stmt (*gsi));
1901 /* Perform re-associations of the plus or minus statement STMT that are
1902 always permitted. Returns true if the CFG was changed. */
1905 associate_plusminus (gimple_stmt_iterator *gsi)
1907 gimple stmt = gsi_stmt (*gsi);
1908 tree rhs1 = gimple_assign_rhs1 (stmt);
1909 tree rhs2 = gimple_assign_rhs2 (stmt);
1910 enum tree_code code = gimple_assign_rhs_code (stmt);
1913 /* We can't reassociate at all for saturating types. */
1914 if (TYPE_SATURATING (TREE_TYPE (rhs1)))
1917 /* First contract negates. */
1922 /* A +- (-B) -> A -+ B. */
1923 if (TREE_CODE (rhs2) == SSA_NAME)
1925 gimple def_stmt = SSA_NAME_DEF_STMT (rhs2);
1926 if (is_gimple_assign (def_stmt)
1927 && gimple_assign_rhs_code (def_stmt) == NEGATE_EXPR
1928 && can_propagate_from (def_stmt))
1930 code = (code == MINUS_EXPR) ? PLUS_EXPR : MINUS_EXPR;
1931 gimple_assign_set_rhs_code (stmt, code);
1932 rhs2 = gimple_assign_rhs1 (def_stmt);
1933 gimple_assign_set_rhs2 (stmt, rhs2);
1934 gimple_set_modified (stmt, true);
1939 /* (-A) + B -> B - A. */
1940 if (TREE_CODE (rhs1) == SSA_NAME
1941 && code == PLUS_EXPR)
1943 gimple def_stmt = SSA_NAME_DEF_STMT (rhs1);
1944 if (is_gimple_assign (def_stmt)
1945 && gimple_assign_rhs_code (def_stmt) == NEGATE_EXPR
1946 && can_propagate_from (def_stmt))
1949 gimple_assign_set_rhs_code (stmt, code);
1951 gimple_assign_set_rhs1 (stmt, rhs1);
1952 rhs2 = gimple_assign_rhs1 (def_stmt);
1953 gimple_assign_set_rhs2 (stmt, rhs2);
1954 gimple_set_modified (stmt, true);
1961 /* We can't reassociate floating-point or fixed-point plus or minus
1962 because of saturation to +-Inf. */
1963 if (FLOAT_TYPE_P (TREE_TYPE (rhs1))
1964 || FIXED_POINT_TYPE_P (TREE_TYPE (rhs1)))
1967 /* Second match patterns that allow contracting a plus-minus pair
1968 irrespective of overflow issues.
1970 (A +- B) - A -> +- B
1972 (CST +- A) +- CST -> CST +- A
1973 (A + CST) +- CST -> A + CST
1976 A - (A +- B) -> -+ B
1977 A +- (B +- A) -> +- B
1978 CST +- (CST +- A) -> CST +- A
1979 CST +- (A +- CST) -> CST +- A
1982 via commutating the addition and contracting operations to zero
1983 by reassociation. */
1985 if (TREE_CODE (rhs1) == SSA_NAME)
1987 gimple def_stmt = SSA_NAME_DEF_STMT (rhs1);
1988 if (is_gimple_assign (def_stmt) && can_propagate_from (def_stmt))
1990 enum tree_code def_code = gimple_assign_rhs_code (def_stmt);
1991 if (def_code == PLUS_EXPR
1992 || def_code == MINUS_EXPR)
1994 tree def_rhs1 = gimple_assign_rhs1 (def_stmt);
1995 tree def_rhs2 = gimple_assign_rhs2 (def_stmt);
1996 if (operand_equal_p (def_rhs1, rhs2, 0)
1997 && code == MINUS_EXPR)
1999 /* (A +- B) - A -> +- B. */
2000 code = ((def_code == PLUS_EXPR)
2001 ? TREE_CODE (def_rhs2) : NEGATE_EXPR);
2004 gimple_assign_set_rhs_with_ops (gsi, code, rhs1, NULL_TREE);
2005 gcc_assert (gsi_stmt (*gsi) == stmt);
2006 gimple_set_modified (stmt, true);
2008 else if (operand_equal_p (def_rhs2, rhs2, 0)
2009 && code != def_code)
2011 /* (A +- B) -+ B -> A. */
2012 code = TREE_CODE (def_rhs1);
2015 gimple_assign_set_rhs_with_ops (gsi, code, rhs1, NULL_TREE);
2016 gcc_assert (gsi_stmt (*gsi) == stmt);
2017 gimple_set_modified (stmt, true);
2019 else if (TREE_CODE (rhs2) == INTEGER_CST
2020 && TREE_CODE (def_rhs1) == INTEGER_CST)
2022 /* (CST +- A) +- CST -> CST +- A. */
2023 tree cst = fold_binary (code, TREE_TYPE (rhs1),
2025 if (cst && !TREE_OVERFLOW (cst))
2028 gimple_assign_set_rhs_code (stmt, code);
2030 gimple_assign_set_rhs1 (stmt, rhs1);
2032 gimple_assign_set_rhs2 (stmt, rhs2);
2033 gimple_set_modified (stmt, true);
2036 else if (TREE_CODE (rhs2) == INTEGER_CST
2037 && TREE_CODE (def_rhs2) == INTEGER_CST
2038 && def_code == PLUS_EXPR)
2040 /* (A + CST) +- CST -> A + CST. */
2041 tree cst = fold_binary (code, TREE_TYPE (rhs1),
2043 if (cst && !TREE_OVERFLOW (cst))
2046 gimple_assign_set_rhs_code (stmt, code);
2048 gimple_assign_set_rhs1 (stmt, rhs1);
2050 gimple_assign_set_rhs2 (stmt, rhs2);
2051 gimple_set_modified (stmt, true);
2055 else if (def_code == BIT_NOT_EXPR
2056 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
2058 tree def_rhs1 = gimple_assign_rhs1 (def_stmt);
2059 if (code == PLUS_EXPR
2060 && operand_equal_p (def_rhs1, rhs2, 0))
2064 rhs1 = build_int_cst_type (TREE_TYPE (rhs2), -1);
2066 gimple_assign_set_rhs_with_ops (gsi, code, rhs1, NULL_TREE);
2067 gcc_assert (gsi_stmt (*gsi) == stmt);
2068 gimple_set_modified (stmt, true);
2070 else if (code == PLUS_EXPR
2071 && integer_onep (rhs1))
2077 gimple_assign_set_rhs_with_ops (gsi, code, rhs1, NULL_TREE);
2078 gcc_assert (gsi_stmt (*gsi) == stmt);
2079 gimple_set_modified (stmt, true);
2085 if (rhs2 && TREE_CODE (rhs2) == SSA_NAME)
2087 gimple def_stmt = SSA_NAME_DEF_STMT (rhs2);
2088 if (is_gimple_assign (def_stmt) && can_propagate_from (def_stmt))
2090 enum tree_code def_code = gimple_assign_rhs_code (def_stmt);
2091 if (def_code == PLUS_EXPR
2092 || def_code == MINUS_EXPR)
2094 tree def_rhs1 = gimple_assign_rhs1 (def_stmt);
2095 tree def_rhs2 = gimple_assign_rhs2 (def_stmt);
2096 if (operand_equal_p (def_rhs1, rhs1, 0)
2097 && code == MINUS_EXPR)
2099 /* A - (A +- B) -> -+ B. */
2100 code = ((def_code == PLUS_EXPR)
2101 ? NEGATE_EXPR : TREE_CODE (def_rhs2));
2104 gimple_assign_set_rhs_with_ops (gsi, code, rhs1, NULL_TREE);
2105 gcc_assert (gsi_stmt (*gsi) == stmt);
2106 gimple_set_modified (stmt, true);
2108 else if (operand_equal_p (def_rhs2, rhs1, 0)
2109 && code != def_code)
2111 /* A +- (B +- A) -> +- B. */
2112 code = ((code == PLUS_EXPR)
2113 ? TREE_CODE (def_rhs1) : NEGATE_EXPR);
2116 gimple_assign_set_rhs_with_ops (gsi, code, rhs1, NULL_TREE);
2117 gcc_assert (gsi_stmt (*gsi) == stmt);
2118 gimple_set_modified (stmt, true);
2120 else if (TREE_CODE (rhs1) == INTEGER_CST
2121 && TREE_CODE (def_rhs1) == INTEGER_CST)
2123 /* CST +- (CST +- A) -> CST +- A. */
2124 tree cst = fold_binary (code, TREE_TYPE (rhs2),
2126 if (cst && !TREE_OVERFLOW (cst))
2128 code = (code == def_code ? PLUS_EXPR : MINUS_EXPR);
2129 gimple_assign_set_rhs_code (stmt, code);
2131 gimple_assign_set_rhs1 (stmt, rhs1);
2133 gimple_assign_set_rhs2 (stmt, rhs2);
2134 gimple_set_modified (stmt, true);
2137 else if (TREE_CODE (rhs1) == INTEGER_CST
2138 && TREE_CODE (def_rhs2) == INTEGER_CST)
2140 /* CST +- (A +- CST) -> CST +- A. */
2141 tree cst = fold_binary (def_code == code
2142 ? PLUS_EXPR : MINUS_EXPR,
2145 if (cst && !TREE_OVERFLOW (cst))
2148 gimple_assign_set_rhs1 (stmt, rhs1);
2150 gimple_assign_set_rhs2 (stmt, rhs2);
2151 gimple_set_modified (stmt, true);
2155 else if (def_code == BIT_NOT_EXPR
2156 && INTEGRAL_TYPE_P (TREE_TYPE (rhs2)))
2158 tree def_rhs1 = gimple_assign_rhs1 (def_stmt);
2159 if (code == PLUS_EXPR
2160 && operand_equal_p (def_rhs1, rhs1, 0))
2164 rhs1 = build_int_cst_type (TREE_TYPE (rhs1), -1);
2166 gimple_assign_set_rhs_with_ops (gsi, code, rhs1, NULL_TREE);
2167 gcc_assert (gsi_stmt (*gsi) == stmt);
2168 gimple_set_modified (stmt, true);
2175 if (gimple_modified_p (stmt))
2177 fold_stmt_inplace (gsi);
2179 if (maybe_clean_or_replace_eh_stmt (stmt, stmt)
2180 && gimple_purge_dead_eh_edges (gimple_bb (stmt)))
2187 /* Combine two conversions in a row for the second conversion at *GSI.
2188 Returns 1 if there were any changes made, 2 if cfg-cleanup needs to
2189 run. Else it returns 0. */
2192 combine_conversions (gimple_stmt_iterator *gsi)
2194 gimple stmt = gsi_stmt (*gsi);
2197 enum tree_code code = gimple_assign_rhs_code (stmt);
2199 gcc_checking_assert (CONVERT_EXPR_CODE_P (code)
2200 || code == FLOAT_EXPR
2201 || code == FIX_TRUNC_EXPR);
2203 lhs = gimple_assign_lhs (stmt);
2204 op0 = gimple_assign_rhs1 (stmt);
2205 if (useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (op0)))
2207 gimple_assign_set_rhs_code (stmt, TREE_CODE (op0));
2211 if (TREE_CODE (op0) != SSA_NAME)
2214 def_stmt = SSA_NAME_DEF_STMT (op0);
2215 if (!is_gimple_assign (def_stmt))
2218 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)))
2220 tree defop0 = gimple_assign_rhs1 (def_stmt);
2221 tree type = TREE_TYPE (lhs);
2222 tree inside_type = TREE_TYPE (defop0);
2223 tree inter_type = TREE_TYPE (op0);
2224 int inside_int = INTEGRAL_TYPE_P (inside_type);
2225 int inside_ptr = POINTER_TYPE_P (inside_type);
2226 int inside_float = FLOAT_TYPE_P (inside_type);
2227 int inside_vec = TREE_CODE (inside_type) == VECTOR_TYPE;
2228 unsigned int inside_prec = TYPE_PRECISION (inside_type);
2229 int inside_unsignedp = TYPE_UNSIGNED (inside_type);
2230 int inter_int = INTEGRAL_TYPE_P (inter_type);
2231 int inter_ptr = POINTER_TYPE_P (inter_type);
2232 int inter_float = FLOAT_TYPE_P (inter_type);
2233 int inter_vec = TREE_CODE (inter_type) == VECTOR_TYPE;
2234 unsigned int inter_prec = TYPE_PRECISION (inter_type);
2235 int inter_unsignedp = TYPE_UNSIGNED (inter_type);
2236 int final_int = INTEGRAL_TYPE_P (type);
2237 int final_ptr = POINTER_TYPE_P (type);
2238 int final_float = FLOAT_TYPE_P (type);
2239 int final_vec = TREE_CODE (type) == VECTOR_TYPE;
2240 unsigned int final_prec = TYPE_PRECISION (type);
2241 int final_unsignedp = TYPE_UNSIGNED (type);
2243 /* In addition to the cases of two conversions in a row
2244 handled below, if we are converting something to its own
2245 type via an object of identical or wider precision, neither
2246 conversion is needed. */
2247 if (useless_type_conversion_p (type, inside_type)
2248 && (((inter_int || inter_ptr) && final_int)
2249 || (inter_float && final_float))
2250 && inter_prec >= final_prec)
2252 gimple_assign_set_rhs1 (stmt, unshare_expr (defop0));
2253 gimple_assign_set_rhs_code (stmt, TREE_CODE (defop0));
2255 return remove_prop_source_from_use (op0) ? 2 : 1;
2258 /* Likewise, if the intermediate and initial types are either both
2259 float or both integer, we don't need the middle conversion if the
2260 former is wider than the latter and doesn't change the signedness
2261 (for integers). Avoid this if the final type is a pointer since
2262 then we sometimes need the middle conversion. Likewise if the
2263 final type has a precision not equal to the size of its mode. */
2264 if (((inter_int && inside_int)
2265 || (inter_float && inside_float)
2266 || (inter_vec && inside_vec))
2267 && inter_prec >= inside_prec
2268 && (inter_float || inter_vec
2269 || inter_unsignedp == inside_unsignedp)
2270 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (type))
2271 && TYPE_MODE (type) == TYPE_MODE (inter_type))
2273 && (! final_vec || inter_prec == inside_prec))
2275 gimple_assign_set_rhs1 (stmt, defop0);
2277 return remove_prop_source_from_use (op0) ? 2 : 1;
2280 /* If we have a sign-extension of a zero-extended value, we can
2281 replace that by a single zero-extension. */
2282 if (inside_int && inter_int && final_int
2283 && inside_prec < inter_prec && inter_prec < final_prec
2284 && inside_unsignedp && !inter_unsignedp)
2286 gimple_assign_set_rhs1 (stmt, defop0);
2288 return remove_prop_source_from_use (op0) ? 2 : 1;
2291 /* Two conversions in a row are not needed unless:
2292 - some conversion is floating-point (overstrict for now), or
2293 - some conversion is a vector (overstrict for now), or
2294 - the intermediate type is narrower than both initial and
2296 - the intermediate type and innermost type differ in signedness,
2297 and the outermost type is wider than the intermediate, or
2298 - the initial type is a pointer type and the precisions of the
2299 intermediate and final types differ, or
2300 - the final type is a pointer type and the precisions of the
2301 initial and intermediate types differ. */
2302 if (! inside_float && ! inter_float && ! final_float
2303 && ! inside_vec && ! inter_vec && ! final_vec
2304 && (inter_prec >= inside_prec || inter_prec >= final_prec)
2305 && ! (inside_int && inter_int
2306 && inter_unsignedp != inside_unsignedp
2307 && inter_prec < final_prec)
2308 && ((inter_unsignedp && inter_prec > inside_prec)
2309 == (final_unsignedp && final_prec > inter_prec))
2310 && ! (inside_ptr && inter_prec != final_prec)
2311 && ! (final_ptr && inside_prec != inter_prec)
2312 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (type))
2313 && TYPE_MODE (type) == TYPE_MODE (inter_type)))
2315 gimple_assign_set_rhs1 (stmt, defop0);
2317 return remove_prop_source_from_use (op0) ? 2 : 1;
2320 /* A truncation to an unsigned type should be canonicalized as
2321 bitwise and of a mask. */
2322 if (final_int && inter_int && inside_int
2323 && final_prec == inside_prec
2324 && final_prec > inter_prec
2328 tem = fold_build2 (BIT_AND_EXPR, inside_type,
2331 (inside_type, double_int_mask (inter_prec)));
2332 if (!useless_type_conversion_p (type, inside_type))
2334 tem = force_gimple_operand_gsi (gsi, tem, true, NULL_TREE, true,
2336 gimple_assign_set_rhs1 (stmt, tem);
2339 gimple_assign_set_rhs_from_tree (gsi, tem);
2340 update_stmt (gsi_stmt (*gsi));
2348 /* Main entry point for the forward propagation and statement combine
2352 ssa_forward_propagate_and_combine (void)
2355 unsigned int todoflags = 0;
2357 cfg_changed = false;
2361 gimple_stmt_iterator gsi, prev;
2362 bool prev_initialized;
2364 /* Apply forward propagation to all stmts in the basic-block.
2365 Note we update GSI within the loop as necessary. */
2366 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); )
2368 gimple stmt = gsi_stmt (gsi);
2370 enum tree_code code;
2372 if (!is_gimple_assign (stmt))
2378 lhs = gimple_assign_lhs (stmt);
2379 rhs = gimple_assign_rhs1 (stmt);
2380 code = gimple_assign_rhs_code (stmt);
2381 if (TREE_CODE (lhs) != SSA_NAME
2382 || has_zero_uses (lhs))
2388 /* If this statement sets an SSA_NAME to an address,
2389 try to propagate the address into the uses of the SSA_NAME. */
2390 if (code == ADDR_EXPR
2391 /* Handle pointer conversions on invariant addresses
2392 as well, as this is valid gimple. */
2393 || (CONVERT_EXPR_CODE_P (code)
2394 && TREE_CODE (rhs) == ADDR_EXPR
2395 && POINTER_TYPE_P (TREE_TYPE (lhs))))
2397 tree base = get_base_address (TREE_OPERAND (rhs, 0));
2400 || decl_address_invariant_p (base))
2401 && !stmt_references_abnormal_ssa_name (stmt)
2402 && forward_propagate_addr_expr (lhs, rhs))
2404 release_defs (stmt);
2405 todoflags |= TODO_remove_unused_locals;
2406 gsi_remove (&gsi, true);
2411 else if (code == POINTER_PLUS_EXPR)
2413 tree off = gimple_assign_rhs2 (stmt);
2414 if (TREE_CODE (off) == INTEGER_CST
2415 && can_propagate_from (stmt)
2416 && !simple_iv_increment_p (stmt)
2417 /* ??? Better adjust the interface to that function
2418 instead of building new trees here. */
2419 && forward_propagate_addr_expr
2421 build1_loc (gimple_location (stmt),
2422 ADDR_EXPR, TREE_TYPE (rhs),
2423 fold_build2 (MEM_REF,
2424 TREE_TYPE (TREE_TYPE (rhs)),
2426 fold_convert (ptr_type_node,
2429 release_defs (stmt);
2430 todoflags |= TODO_remove_unused_locals;
2431 gsi_remove (&gsi, true);
2433 else if (is_gimple_min_invariant (rhs))
2435 /* Make sure to fold &a[0] + off_1 here. */
2436 fold_stmt_inplace (&gsi);
2438 if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR)
2444 else if (TREE_CODE_CLASS (code) == tcc_comparison)
2446 if (forward_propagate_comparison (stmt))
2454 /* Combine stmts with the stmts defining their operands.
2455 Note we update GSI within the loop as necessary. */
2456 prev_initialized = false;
2457 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi);)
2459 gimple stmt = gsi_stmt (gsi);
2460 bool changed = false;
2462 switch (gimple_code (stmt))
2466 tree rhs1 = gimple_assign_rhs1 (stmt);
2467 enum tree_code code = gimple_assign_rhs_code (stmt);
2469 if ((code == BIT_NOT_EXPR
2470 || code == NEGATE_EXPR)
2471 && TREE_CODE (rhs1) == SSA_NAME)
2472 changed = simplify_not_neg_expr (&gsi);
2473 else if (code == COND_EXPR)
2475 /* In this case the entire COND_EXPR is in rhs1. */
2476 changed |= forward_propagate_into_cond (&gsi);
2477 stmt = gsi_stmt (gsi);
2479 else if (TREE_CODE_CLASS (code) == tcc_comparison)
2482 did_something = forward_propagate_into_comparison (&gsi);
2483 if (did_something == 2)
2485 changed = did_something != 0;
2487 else if (code == BIT_AND_EXPR
2488 || code == BIT_IOR_EXPR
2489 || code == BIT_XOR_EXPR)
2490 changed = simplify_bitwise_binary (&gsi);
2491 else if (code == PLUS_EXPR
2492 || code == MINUS_EXPR)
2493 changed = associate_plusminus (&gsi);
2494 else if (CONVERT_EXPR_CODE_P (code)
2495 || code == FLOAT_EXPR
2496 || code == FIX_TRUNC_EXPR)
2498 int did_something = combine_conversions (&gsi);
2499 if (did_something == 2)
2501 changed = did_something != 0;
2507 changed = simplify_gimple_switch (stmt);
2513 did_something = forward_propagate_into_gimple_cond (stmt);
2514 if (did_something == 2)
2516 changed = did_something != 0;
2522 tree callee = gimple_call_fndecl (stmt);
2523 if (callee != NULL_TREE
2524 && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
2525 changed = simplify_builtin_call (&gsi, callee);
2534 /* If the stmt changed then re-visit it and the statements
2535 inserted before it. */
2536 if (!prev_initialized)
2537 gsi = gsi_start_bb (bb);
2547 prev_initialized = true;
2554 todoflags |= TODO_cleanup_cfg;
2561 gate_forwprop (void)
2563 return flag_tree_forwprop;
2566 struct gimple_opt_pass pass_forwprop =
2570 "forwprop", /* name */
2571 gate_forwprop, /* gate */
2572 ssa_forward_propagate_and_combine, /* execute */
2575 0, /* static_pass_number */
2576 TV_TREE_FORWPROP, /* tv_id */
2577 PROP_cfg | PROP_ssa, /* properties_required */
2578 0, /* properties_provided */
2579 0, /* properties_destroyed */
2580 0, /* todo_flags_start */
2583 | TODO_verify_ssa /* todo_flags_finish */