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);
480 fold_stmt_inplace (stmt);
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 use_stmt = gsi_stmt (*use_stmt_gsi);
769 /* That should have created gimple, so there is no need to
770 record information to undo the propagation. */
771 fold_stmt_inplace (use_stmt);
772 tidy_after_forward_propagate_addr (use_stmt);
776 /* NAME is a SSA_NAME representing DEF_RHS which is of the form
777 ADDR_EXPR <whatever>.
779 Try to forward propagate the ADDR_EXPR into the use USE_STMT.
780 Often this will allow for removal of an ADDR_EXPR and INDIRECT_REF
781 node or for recovery of array indexing from pointer arithmetic.
783 Return true if the propagation was successful (the propagation can
784 be not totally successful, yet things may have been changed). */
787 forward_propagate_addr_expr_1 (tree name, tree def_rhs,
788 gimple_stmt_iterator *use_stmt_gsi,
791 tree lhs, rhs, rhs2, array_ref;
792 gimple use_stmt = gsi_stmt (*use_stmt_gsi);
793 enum tree_code rhs_code;
796 gcc_assert (TREE_CODE (def_rhs) == ADDR_EXPR);
798 lhs = gimple_assign_lhs (use_stmt);
799 rhs_code = gimple_assign_rhs_code (use_stmt);
800 rhs = gimple_assign_rhs1 (use_stmt);
802 /* Trivial cases. The use statement could be a trivial copy or a
803 useless conversion. Recurse to the uses of the lhs as copyprop does
804 not copy through different variant pointers and FRE does not catch
805 all useless conversions. Treat the case of a single-use name and
806 a conversion to def_rhs type separate, though. */
807 if (TREE_CODE (lhs) == SSA_NAME
808 && ((rhs_code == SSA_NAME && rhs == name)
809 || CONVERT_EXPR_CODE_P (rhs_code)))
811 /* Only recurse if we don't deal with a single use or we cannot
812 do the propagation to the current statement. In particular
813 we can end up with a conversion needed for a non-invariant
814 address which we cannot do in a single statement. */
816 || (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (def_rhs))
817 && (!is_gimple_min_invariant (def_rhs)
818 || (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
819 && POINTER_TYPE_P (TREE_TYPE (def_rhs))
820 && (TYPE_PRECISION (TREE_TYPE (lhs))
821 > TYPE_PRECISION (TREE_TYPE (def_rhs)))))))
822 return forward_propagate_addr_expr (lhs, def_rhs);
824 gimple_assign_set_rhs1 (use_stmt, unshare_expr (def_rhs));
825 if (useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (def_rhs)))
826 gimple_assign_set_rhs_code (use_stmt, TREE_CODE (def_rhs));
828 gimple_assign_set_rhs_code (use_stmt, NOP_EXPR);
832 /* Propagate through constant pointer adjustments. */
833 if (TREE_CODE (lhs) == SSA_NAME
834 && rhs_code == POINTER_PLUS_EXPR
836 && TREE_CODE (gimple_assign_rhs2 (use_stmt)) == INTEGER_CST)
839 /* As we come here with non-invariant addresses in def_rhs we need
840 to make sure we can build a valid constant offsetted address
841 for further propagation. Simply rely on fold building that
842 and check after the fact. */
843 new_def_rhs = fold_build2 (MEM_REF, TREE_TYPE (TREE_TYPE (rhs)),
845 fold_convert (ptr_type_node,
846 gimple_assign_rhs2 (use_stmt)));
847 if (TREE_CODE (new_def_rhs) == MEM_REF
848 && !is_gimple_mem_ref_addr (TREE_OPERAND (new_def_rhs, 0)))
850 new_def_rhs = build_fold_addr_expr_with_type (new_def_rhs,
853 /* Recurse. If we could propagate into all uses of lhs do not
854 bother to replace into the current use but just pretend we did. */
855 if (TREE_CODE (new_def_rhs) == ADDR_EXPR
856 && forward_propagate_addr_expr (lhs, new_def_rhs))
859 if (useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (new_def_rhs)))
860 gimple_assign_set_rhs_with_ops (use_stmt_gsi, TREE_CODE (new_def_rhs),
861 new_def_rhs, NULL_TREE);
862 else if (is_gimple_min_invariant (new_def_rhs))
863 gimple_assign_set_rhs_with_ops (use_stmt_gsi, NOP_EXPR,
864 new_def_rhs, NULL_TREE);
867 gcc_assert (gsi_stmt (*use_stmt_gsi) == use_stmt);
868 update_stmt (use_stmt);
872 /* Now strip away any outer COMPONENT_REF/ARRAY_REF nodes from the LHS.
873 ADDR_EXPR will not appear on the LHS. */
874 lhs = gimple_assign_lhs (use_stmt);
875 while (handled_component_p (lhs))
876 lhs = TREE_OPERAND (lhs, 0);
878 /* Now see if the LHS node is a MEM_REF using NAME. If so,
879 propagate the ADDR_EXPR into the use of NAME and fold the result. */
880 if (TREE_CODE (lhs) == MEM_REF
881 && TREE_OPERAND (lhs, 0) == name)
884 HOST_WIDE_INT def_rhs_offset;
885 /* If the address is invariant we can always fold it. */
886 if ((def_rhs_base = get_addr_base_and_unit_offset (TREE_OPERAND (def_rhs, 0),
889 double_int off = mem_ref_offset (lhs);
891 off = double_int_add (off,
892 shwi_to_double_int (def_rhs_offset));
893 if (TREE_CODE (def_rhs_base) == MEM_REF)
895 off = double_int_add (off, mem_ref_offset (def_rhs_base));
896 new_ptr = TREE_OPERAND (def_rhs_base, 0);
899 new_ptr = build_fold_addr_expr (def_rhs_base);
900 TREE_OPERAND (lhs, 0) = new_ptr;
901 TREE_OPERAND (lhs, 1)
902 = double_int_to_tree (TREE_TYPE (TREE_OPERAND (lhs, 1)), off);
903 tidy_after_forward_propagate_addr (use_stmt);
904 /* Continue propagating into the RHS if this was not the only use. */
908 /* If the LHS is a plain dereference and the value type is the same as
909 that of the pointed-to type of the address we can put the
910 dereferenced address on the LHS preserving the original alias-type. */
911 else if (gimple_assign_lhs (use_stmt) == lhs
912 && useless_type_conversion_p
913 (TREE_TYPE (TREE_OPERAND (def_rhs, 0)),
914 TREE_TYPE (gimple_assign_rhs1 (use_stmt))))
916 tree *def_rhs_basep = &TREE_OPERAND (def_rhs, 0);
917 tree new_offset, new_base, saved;
918 while (handled_component_p (*def_rhs_basep))
919 def_rhs_basep = &TREE_OPERAND (*def_rhs_basep, 0);
920 saved = *def_rhs_basep;
921 if (TREE_CODE (*def_rhs_basep) == MEM_REF)
923 new_base = TREE_OPERAND (*def_rhs_basep, 0);
925 = int_const_binop (PLUS_EXPR, TREE_OPERAND (lhs, 1),
926 TREE_OPERAND (*def_rhs_basep, 1));
930 new_base = build_fold_addr_expr (*def_rhs_basep);
931 new_offset = TREE_OPERAND (lhs, 1);
933 *def_rhs_basep = build2 (MEM_REF, TREE_TYPE (*def_rhs_basep),
934 new_base, new_offset);
935 TREE_THIS_VOLATILE (*def_rhs_basep) = TREE_THIS_VOLATILE (lhs);
936 TREE_THIS_NOTRAP (*def_rhs_basep) = TREE_THIS_NOTRAP (lhs);
937 gimple_assign_set_lhs (use_stmt,
938 unshare_expr (TREE_OPERAND (def_rhs, 0)));
939 *def_rhs_basep = saved;
940 tidy_after_forward_propagate_addr (use_stmt);
941 /* Continue propagating into the RHS if this was not the
947 /* We can have a struct assignment dereferencing our name twice.
948 Note that we didn't propagate into the lhs to not falsely
949 claim we did when propagating into the rhs. */
953 /* Strip away any outer COMPONENT_REF, ARRAY_REF or ADDR_EXPR
954 nodes from the RHS. */
955 rhs = gimple_assign_rhs1 (use_stmt);
956 if (TREE_CODE (rhs) == ADDR_EXPR)
957 rhs = TREE_OPERAND (rhs, 0);
958 while (handled_component_p (rhs))
959 rhs = TREE_OPERAND (rhs, 0);
961 /* Now see if the RHS node is a MEM_REF using NAME. If so,
962 propagate the ADDR_EXPR into the use of NAME and fold the result. */
963 if (TREE_CODE (rhs) == MEM_REF
964 && TREE_OPERAND (rhs, 0) == name)
967 HOST_WIDE_INT def_rhs_offset;
968 if ((def_rhs_base = get_addr_base_and_unit_offset (TREE_OPERAND (def_rhs, 0),
971 double_int off = mem_ref_offset (rhs);
973 off = double_int_add (off,
974 shwi_to_double_int (def_rhs_offset));
975 if (TREE_CODE (def_rhs_base) == MEM_REF)
977 off = double_int_add (off, mem_ref_offset (def_rhs_base));
978 new_ptr = TREE_OPERAND (def_rhs_base, 0);
981 new_ptr = build_fold_addr_expr (def_rhs_base);
982 TREE_OPERAND (rhs, 0) = new_ptr;
983 TREE_OPERAND (rhs, 1)
984 = double_int_to_tree (TREE_TYPE (TREE_OPERAND (rhs, 1)), off);
985 fold_stmt_inplace (use_stmt);
986 tidy_after_forward_propagate_addr (use_stmt);
989 /* If the RHS is a plain dereference and the value type is the same as
990 that of the pointed-to type of the address we can put the
991 dereferenced address on the RHS preserving the original alias-type. */
992 else if (gimple_assign_rhs1 (use_stmt) == rhs
993 && useless_type_conversion_p
994 (TREE_TYPE (gimple_assign_lhs (use_stmt)),
995 TREE_TYPE (TREE_OPERAND (def_rhs, 0))))
997 tree *def_rhs_basep = &TREE_OPERAND (def_rhs, 0);
998 tree new_offset, new_base, saved;
999 while (handled_component_p (*def_rhs_basep))
1000 def_rhs_basep = &TREE_OPERAND (*def_rhs_basep, 0);
1001 saved = *def_rhs_basep;
1002 if (TREE_CODE (*def_rhs_basep) == MEM_REF)
1004 new_base = TREE_OPERAND (*def_rhs_basep, 0);
1006 = int_const_binop (PLUS_EXPR, TREE_OPERAND (rhs, 1),
1007 TREE_OPERAND (*def_rhs_basep, 1));
1011 new_base = build_fold_addr_expr (*def_rhs_basep);
1012 new_offset = TREE_OPERAND (rhs, 1);
1014 *def_rhs_basep = build2 (MEM_REF, TREE_TYPE (*def_rhs_basep),
1015 new_base, new_offset);
1016 TREE_THIS_VOLATILE (*def_rhs_basep) = TREE_THIS_VOLATILE (rhs);
1017 TREE_THIS_NOTRAP (*def_rhs_basep) = TREE_THIS_NOTRAP (rhs);
1018 gimple_assign_set_rhs1 (use_stmt,
1019 unshare_expr (TREE_OPERAND (def_rhs, 0)));
1020 *def_rhs_basep = saved;
1021 fold_stmt_inplace (use_stmt);
1022 tidy_after_forward_propagate_addr (use_stmt);
1027 /* If the use of the ADDR_EXPR is not a POINTER_PLUS_EXPR, there
1028 is nothing to do. */
1029 if (gimple_assign_rhs_code (use_stmt) != POINTER_PLUS_EXPR
1030 || gimple_assign_rhs1 (use_stmt) != name)
1033 /* The remaining cases are all for turning pointer arithmetic into
1034 array indexing. They only apply when we have the address of
1035 element zero in an array. If that is not the case then there
1036 is nothing to do. */
1037 array_ref = TREE_OPERAND (def_rhs, 0);
1038 if ((TREE_CODE (array_ref) != ARRAY_REF
1039 || TREE_CODE (TREE_TYPE (TREE_OPERAND (array_ref, 0))) != ARRAY_TYPE
1040 || TREE_CODE (TREE_OPERAND (array_ref, 1)) != INTEGER_CST)
1041 && TREE_CODE (TREE_TYPE (array_ref)) != ARRAY_TYPE)
1044 rhs2 = gimple_assign_rhs2 (use_stmt);
1045 /* Optimize &x[C1] p+ C2 to &x p+ C3 with C3 = C1 * element_size + C2. */
1046 if (TREE_CODE (rhs2) == INTEGER_CST)
1048 tree new_rhs = build1_loc (gimple_location (use_stmt),
1049 ADDR_EXPR, TREE_TYPE (def_rhs),
1050 fold_build2 (MEM_REF,
1051 TREE_TYPE (TREE_TYPE (def_rhs)),
1052 unshare_expr (def_rhs),
1053 fold_convert (ptr_type_node,
1055 gimple_assign_set_rhs_from_tree (use_stmt_gsi, new_rhs);
1056 use_stmt = gsi_stmt (*use_stmt_gsi);
1057 update_stmt (use_stmt);
1058 tidy_after_forward_propagate_addr (use_stmt);
1062 /* Try to optimize &x[0] p+ OFFSET where OFFSET is defined by
1063 converting a multiplication of an index by the size of the
1064 array elements, then the result is converted into the proper
1065 type for the arithmetic. */
1066 if (TREE_CODE (rhs2) == SSA_NAME
1067 && (TREE_CODE (array_ref) != ARRAY_REF
1068 || integer_zerop (TREE_OPERAND (array_ref, 1)))
1069 && useless_type_conversion_p (TREE_TYPE (name), TREE_TYPE (def_rhs))
1070 /* Avoid problems with IVopts creating PLUS_EXPRs with a
1071 different type than their operands. */
1072 && useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (def_rhs)))
1073 return forward_propagate_addr_into_variable_array_index (rhs2, def_rhs,
1078 /* STMT is a statement of the form SSA_NAME = ADDR_EXPR <whatever>.
1080 Try to forward propagate the ADDR_EXPR into all uses of the SSA_NAME.
1081 Often this will allow for removal of an ADDR_EXPR and INDIRECT_REF
1082 node or for recovery of array indexing from pointer arithmetic.
1083 Returns true, if all uses have been propagated into. */
1086 forward_propagate_addr_expr (tree name, tree rhs)
1088 int stmt_loop_depth = gimple_bb (SSA_NAME_DEF_STMT (name))->loop_depth;
1089 imm_use_iterator iter;
1092 bool single_use_p = has_single_use (name);
1094 FOR_EACH_IMM_USE_STMT (use_stmt, iter, name)
1099 /* If the use is not in a simple assignment statement, then
1100 there is nothing we can do. */
1101 if (gimple_code (use_stmt) != GIMPLE_ASSIGN)
1103 if (!is_gimple_debug (use_stmt))
1108 /* If the use is in a deeper loop nest, then we do not want
1109 to propagate non-invariant ADDR_EXPRs into the loop as that
1110 is likely adding expression evaluations into the loop. */
1111 if (gimple_bb (use_stmt)->loop_depth > stmt_loop_depth
1112 && !is_gimple_min_invariant (rhs))
1119 gimple_stmt_iterator gsi = gsi_for_stmt (use_stmt);
1120 result = forward_propagate_addr_expr_1 (name, rhs, &gsi,
1122 /* If the use has moved to a different statement adjust
1123 the update machinery for the old statement too. */
1124 if (use_stmt != gsi_stmt (gsi))
1126 update_stmt (use_stmt);
1127 use_stmt = gsi_stmt (gsi);
1130 update_stmt (use_stmt);
1134 /* Remove intermediate now unused copy and conversion chains. */
1135 use_rhs = gimple_assign_rhs1 (use_stmt);
1137 && TREE_CODE (gimple_assign_lhs (use_stmt)) == SSA_NAME
1138 && TREE_CODE (use_rhs) == SSA_NAME
1139 && has_zero_uses (gimple_assign_lhs (use_stmt)))
1141 gimple_stmt_iterator gsi = gsi_for_stmt (use_stmt);
1142 release_defs (use_stmt);
1143 gsi_remove (&gsi, true);
1147 return all && has_zero_uses (name);
1151 /* Forward propagate the comparison defined in STMT like
1152 cond_1 = x CMP y to uses of the form
1156 Returns true if stmt is now unused. */
1159 forward_propagate_comparison (gimple stmt)
1161 tree name = gimple_assign_lhs (stmt);
1163 tree tmp = NULL_TREE;
1164 gimple_stmt_iterator gsi;
1165 enum tree_code code;
1168 /* Don't propagate ssa names that occur in abnormal phis. */
1169 if ((TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
1170 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_assign_rhs1 (stmt)))
1171 || (TREE_CODE (gimple_assign_rhs2 (stmt)) == SSA_NAME
1172 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_assign_rhs2 (stmt))))
1175 /* Do not un-cse comparisons. But propagate through copies. */
1176 use_stmt = get_prop_dest_stmt (name, &name);
1178 || !is_gimple_assign (use_stmt))
1181 code = gimple_assign_rhs_code (use_stmt);
1182 lhs = gimple_assign_lhs (use_stmt);
1183 if (!INTEGRAL_TYPE_P (TREE_TYPE (lhs)))
1186 /* We can propagate the condition into a statement that
1187 computes the logical negation of the comparison result. */
1188 if ((code == BIT_NOT_EXPR
1189 && TYPE_PRECISION (TREE_TYPE (lhs)) == 1)
1190 || (code == BIT_XOR_EXPR
1191 && integer_onep (gimple_assign_rhs2 (use_stmt))))
1193 tree type = TREE_TYPE (gimple_assign_rhs1 (stmt));
1194 bool nans = HONOR_NANS (TYPE_MODE (type));
1195 enum tree_code inv_code;
1196 inv_code = invert_tree_comparison (gimple_assign_rhs_code (stmt), nans);
1197 if (inv_code == ERROR_MARK)
1200 tmp = build2 (inv_code, TREE_TYPE (lhs), gimple_assign_rhs1 (stmt),
1201 gimple_assign_rhs2 (stmt));
1206 gsi = gsi_for_stmt (use_stmt);
1207 gimple_assign_set_rhs_from_tree (&gsi, unshare_expr (tmp));
1208 use_stmt = gsi_stmt (gsi);
1209 update_stmt (use_stmt);
1211 if (dump_file && (dump_flags & TDF_DETAILS))
1213 fprintf (dump_file, " Replaced '");
1214 print_gimple_expr (dump_file, stmt, 0, dump_flags);
1215 fprintf (dump_file, "' with '");
1216 print_gimple_expr (dump_file, use_stmt, 0, dump_flags);
1217 fprintf (dump_file, "'\n");
1220 /* Remove defining statements. */
1221 return remove_prop_source_from_use (name);
1225 /* If we have lhs = ~x (STMT), look and see if earlier we had x = ~y.
1226 If so, we can change STMT into lhs = y which can later be copy
1227 propagated. Similarly for negation.
1229 This could trivially be formulated as a forward propagation
1230 to immediate uses. However, we already had an implementation
1231 from DOM which used backward propagation via the use-def links.
1233 It turns out that backward propagation is actually faster as
1234 there's less work to do for each NOT/NEG expression we find.
1235 Backwards propagation needs to look at the statement in a single
1236 backlink. Forward propagation needs to look at potentially more
1237 than one forward link.
1239 Returns true when the statement was changed. */
1242 simplify_not_neg_expr (gimple_stmt_iterator *gsi_p)
1244 gimple stmt = gsi_stmt (*gsi_p);
1245 tree rhs = gimple_assign_rhs1 (stmt);
1246 gimple rhs_def_stmt = SSA_NAME_DEF_STMT (rhs);
1248 /* See if the RHS_DEF_STMT has the same form as our statement. */
1249 if (is_gimple_assign (rhs_def_stmt)
1250 && gimple_assign_rhs_code (rhs_def_stmt) == gimple_assign_rhs_code (stmt))
1252 tree rhs_def_operand = gimple_assign_rhs1 (rhs_def_stmt);
1254 /* Verify that RHS_DEF_OPERAND is a suitable SSA_NAME. */
1255 if (TREE_CODE (rhs_def_operand) == SSA_NAME
1256 && ! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs_def_operand))
1258 gimple_assign_set_rhs_from_tree (gsi_p, rhs_def_operand);
1259 stmt = gsi_stmt (*gsi_p);
1268 /* STMT is a SWITCH_EXPR for which we attempt to find equivalent forms of
1269 the condition which we may be able to optimize better. */
1272 simplify_gimple_switch (gimple stmt)
1274 tree cond = gimple_switch_index (stmt);
1278 /* The optimization that we really care about is removing unnecessary
1279 casts. That will let us do much better in propagating the inferred
1280 constant at the switch target. */
1281 if (TREE_CODE (cond) == SSA_NAME)
1283 def_stmt = SSA_NAME_DEF_STMT (cond);
1284 if (is_gimple_assign (def_stmt))
1286 if (gimple_assign_rhs_code (def_stmt) == NOP_EXPR)
1291 def = gimple_assign_rhs1 (def_stmt);
1293 /* ??? Why was Jeff testing this? We are gimple... */
1294 gcc_checking_assert (is_gimple_val (def));
1296 to = TREE_TYPE (cond);
1297 ti = TREE_TYPE (def);
1299 /* If we have an extension that preserves value, then we
1300 can copy the source value into the switch. */
1302 need_precision = TYPE_PRECISION (ti);
1304 if (! INTEGRAL_TYPE_P (ti))
1306 else if (TYPE_UNSIGNED (to) && !TYPE_UNSIGNED (ti))
1308 else if (!TYPE_UNSIGNED (to) && TYPE_UNSIGNED (ti))
1309 need_precision += 1;
1310 if (TYPE_PRECISION (to) < need_precision)
1315 gimple_switch_set_index (stmt, def);
1326 /* For pointers p2 and p1 return p2 - p1 if the
1327 difference is known and constant, otherwise return NULL. */
1330 constant_pointer_difference (tree p1, tree p2)
1333 #define CPD_ITERATIONS 5
1334 tree exps[2][CPD_ITERATIONS];
1335 tree offs[2][CPD_ITERATIONS];
1338 for (i = 0; i < 2; i++)
1340 tree p = i ? p1 : p2;
1341 tree off = size_zero_node;
1343 enum tree_code code;
1345 /* For each of p1 and p2 we need to iterate at least
1346 twice, to handle ADDR_EXPR directly in p1/p2,
1347 SSA_NAME with ADDR_EXPR or POINTER_PLUS_EXPR etc.
1348 on definition's stmt RHS. Iterate a few extra times. */
1352 if (!POINTER_TYPE_P (TREE_TYPE (p)))
1354 if (TREE_CODE (p) == ADDR_EXPR)
1356 tree q = TREE_OPERAND (p, 0);
1357 HOST_WIDE_INT offset;
1358 tree base = get_addr_base_and_unit_offset (q, &offset);
1363 off = size_binop (PLUS_EXPR, off, size_int (offset));
1365 if (TREE_CODE (q) == MEM_REF
1366 && TREE_CODE (TREE_OPERAND (q, 0)) == SSA_NAME)
1368 p = TREE_OPERAND (q, 0);
1369 off = size_binop (PLUS_EXPR, off,
1370 double_int_to_tree (sizetype,
1371 mem_ref_offset (q)));
1380 if (TREE_CODE (p) != SSA_NAME)
1384 if (j == CPD_ITERATIONS)
1386 stmt = SSA_NAME_DEF_STMT (p);
1387 if (!is_gimple_assign (stmt) || gimple_assign_lhs (stmt) != p)
1389 code = gimple_assign_rhs_code (stmt);
1390 if (code == POINTER_PLUS_EXPR)
1392 if (TREE_CODE (gimple_assign_rhs2 (stmt)) != INTEGER_CST)
1394 off = size_binop (PLUS_EXPR, off, gimple_assign_rhs2 (stmt));
1395 p = gimple_assign_rhs1 (stmt);
1397 else if (code == ADDR_EXPR || code == NOP_EXPR)
1398 p = gimple_assign_rhs1 (stmt);
1406 for (i = 0; i < cnt[0]; i++)
1407 for (j = 0; j < cnt[1]; j++)
1408 if (exps[0][i] == exps[1][j])
1409 return size_binop (MINUS_EXPR, offs[0][i], offs[1][j]);
1414 /* *GSI_P is a GIMPLE_CALL to a builtin function.
1416 memcpy (p, "abcd", 4);
1417 memset (p + 4, ' ', 3);
1419 memcpy (p, "abcd ", 7);
1420 call if the latter can be stored by pieces during expansion. */
1423 simplify_builtin_call (gimple_stmt_iterator *gsi_p, tree callee2)
1425 gimple stmt1, stmt2 = gsi_stmt (*gsi_p);
1426 tree vuse = gimple_vuse (stmt2);
1429 stmt1 = SSA_NAME_DEF_STMT (vuse);
1431 switch (DECL_FUNCTION_CODE (callee2))
1433 case BUILT_IN_MEMSET:
1434 if (gimple_call_num_args (stmt2) != 3
1435 || gimple_call_lhs (stmt2)
1437 || BITS_PER_UNIT != 8)
1442 tree ptr1, src1, str1, off1, len1, lhs1;
1443 tree ptr2 = gimple_call_arg (stmt2, 0);
1444 tree val2 = gimple_call_arg (stmt2, 1);
1445 tree len2 = gimple_call_arg (stmt2, 2);
1446 tree diff, vdef, new_str_cst;
1448 unsigned int ptr1_align;
1449 unsigned HOST_WIDE_INT src_len;
1451 use_operand_p use_p;
1453 if (!host_integerp (val2, 0)
1454 || !host_integerp (len2, 1))
1456 if (is_gimple_call (stmt1))
1458 /* If first stmt is a call, it needs to be memcpy
1459 or mempcpy, with string literal as second argument and
1461 callee1 = gimple_call_fndecl (stmt1);
1462 if (callee1 == NULL_TREE
1463 || DECL_BUILT_IN_CLASS (callee1) != BUILT_IN_NORMAL
1464 || gimple_call_num_args (stmt1) != 3)
1466 if (DECL_FUNCTION_CODE (callee1) != BUILT_IN_MEMCPY
1467 && DECL_FUNCTION_CODE (callee1) != BUILT_IN_MEMPCPY)
1469 ptr1 = gimple_call_arg (stmt1, 0);
1470 src1 = gimple_call_arg (stmt1, 1);
1471 len1 = gimple_call_arg (stmt1, 2);
1472 lhs1 = gimple_call_lhs (stmt1);
1473 if (!host_integerp (len1, 1))
1475 str1 = string_constant (src1, &off1);
1476 if (str1 == NULL_TREE)
1478 if (!host_integerp (off1, 1)
1479 || compare_tree_int (off1, TREE_STRING_LENGTH (str1) - 1) > 0
1480 || compare_tree_int (len1, TREE_STRING_LENGTH (str1)
1481 - tree_low_cst (off1, 1)) > 0
1482 || TREE_CODE (TREE_TYPE (str1)) != ARRAY_TYPE
1483 || TYPE_MODE (TREE_TYPE (TREE_TYPE (str1)))
1484 != TYPE_MODE (char_type_node))
1487 else if (gimple_assign_single_p (stmt1))
1489 /* Otherwise look for length 1 memcpy optimized into
1491 ptr1 = gimple_assign_lhs (stmt1);
1492 src1 = gimple_assign_rhs1 (stmt1);
1493 if (TREE_CODE (ptr1) != MEM_REF
1494 || TYPE_MODE (TREE_TYPE (ptr1)) != TYPE_MODE (char_type_node)
1495 || !host_integerp (src1, 0))
1497 ptr1 = build_fold_addr_expr (ptr1);
1498 callee1 = NULL_TREE;
1499 len1 = size_one_node;
1501 off1 = size_zero_node;
1507 diff = constant_pointer_difference (ptr1, ptr2);
1508 if (diff == NULL && lhs1 != NULL)
1510 diff = constant_pointer_difference (lhs1, ptr2);
1511 if (DECL_FUNCTION_CODE (callee1) == BUILT_IN_MEMPCPY
1513 diff = size_binop (PLUS_EXPR, diff,
1514 fold_convert (sizetype, len1));
1516 /* If the difference between the second and first destination pointer
1517 is not constant, or is bigger than memcpy length, bail out. */
1519 || !host_integerp (diff, 1)
1520 || tree_int_cst_lt (len1, diff))
1523 /* Use maximum of difference plus memset length and memcpy length
1524 as the new memcpy length, if it is too big, bail out. */
1525 src_len = tree_low_cst (diff, 1);
1526 src_len += tree_low_cst (len2, 1);
1527 if (src_len < (unsigned HOST_WIDE_INT) tree_low_cst (len1, 1))
1528 src_len = tree_low_cst (len1, 1);
1532 /* If mempcpy value is used elsewhere, bail out, as mempcpy
1533 with bigger length will return different result. */
1534 if (lhs1 != NULL_TREE
1535 && DECL_FUNCTION_CODE (callee1) == BUILT_IN_MEMPCPY
1536 && (TREE_CODE (lhs1) != SSA_NAME
1537 || !single_imm_use (lhs1, &use_p, &use_stmt)
1538 || use_stmt != stmt2))
1541 /* If anything reads memory in between memcpy and memset
1542 call, the modified memcpy call might change it. */
1543 vdef = gimple_vdef (stmt1);
1545 && (!single_imm_use (vdef, &use_p, &use_stmt)
1546 || use_stmt != stmt2))
1549 ptr1_align = get_pointer_alignment (ptr1);
1550 /* Construct the new source string literal. */
1551 src_buf = XALLOCAVEC (char, src_len + 1);
1554 TREE_STRING_POINTER (str1) + tree_low_cst (off1, 1),
1555 tree_low_cst (len1, 1));
1557 src_buf[0] = tree_low_cst (src1, 0);
1558 memset (src_buf + tree_low_cst (diff, 1),
1559 tree_low_cst (val2, 1), tree_low_cst (len2, 1));
1560 src_buf[src_len] = '\0';
1561 /* Neither builtin_strncpy_read_str nor builtin_memcpy_read_str
1562 handle embedded '\0's. */
1563 if (strlen (src_buf) != src_len)
1565 rtl_profile_for_bb (gimple_bb (stmt2));
1566 /* If the new memcpy wouldn't be emitted by storing the literal
1567 by pieces, this optimization might enlarge .rodata too much,
1568 as commonly used string literals couldn't be shared any
1570 if (!can_store_by_pieces (src_len,
1571 builtin_strncpy_read_str,
1572 src_buf, ptr1_align, false))
1575 new_str_cst = build_string_literal (src_len, src_buf);
1578 /* If STMT1 is a mem{,p}cpy call, adjust it and remove
1580 if (lhs1 && DECL_FUNCTION_CODE (callee1) == BUILT_IN_MEMPCPY)
1581 gimple_call_set_lhs (stmt1, NULL_TREE);
1582 gimple_call_set_arg (stmt1, 1, new_str_cst);
1583 gimple_call_set_arg (stmt1, 2,
1584 build_int_cst (TREE_TYPE (len1), src_len));
1585 update_stmt (stmt1);
1586 unlink_stmt_vdef (stmt2);
1587 gsi_remove (gsi_p, true);
1588 release_defs (stmt2);
1589 if (lhs1 && DECL_FUNCTION_CODE (callee1) == BUILT_IN_MEMPCPY)
1590 release_ssa_name (lhs1);
1595 /* Otherwise, if STMT1 is length 1 memcpy optimized into
1596 assignment, remove STMT1 and change memset call into
1598 gimple_stmt_iterator gsi = gsi_for_stmt (stmt1);
1600 if (!is_gimple_val (ptr1))
1601 ptr1 = force_gimple_operand_gsi (gsi_p, ptr1, true, NULL_TREE,
1602 true, GSI_SAME_STMT);
1603 gimple_call_set_fndecl (stmt2, built_in_decls [BUILT_IN_MEMCPY]);
1604 gimple_call_set_arg (stmt2, 0, ptr1);
1605 gimple_call_set_arg (stmt2, 1, new_str_cst);
1606 gimple_call_set_arg (stmt2, 2,
1607 build_int_cst (TREE_TYPE (len2), src_len));
1608 unlink_stmt_vdef (stmt1);
1609 gsi_remove (&gsi, true);
1610 release_defs (stmt1);
1611 update_stmt (stmt2);
1622 /* Checks if expression has type of one-bit precision, or is a known
1623 truth-valued expression. */
1625 truth_valued_ssa_name (tree name)
1628 tree type = TREE_TYPE (name);
1630 if (!INTEGRAL_TYPE_P (type))
1632 /* Don't check here for BOOLEAN_TYPE as the precision isn't
1633 necessarily one and so ~X is not equal to !X. */
1634 if (TYPE_PRECISION (type) == 1)
1636 def = SSA_NAME_DEF_STMT (name);
1637 if (is_gimple_assign (def))
1638 return truth_value_p (gimple_assign_rhs_code (def));
1642 /* Helper routine for simplify_bitwise_binary_1 function.
1643 Return for the SSA name NAME the expression X if it mets condition
1644 NAME = !X. Otherwise return NULL_TREE.
1645 Detected patterns for NAME = !X are:
1646 !X and X == 0 for X with integral type.
1647 X ^ 1, X != 1,or ~X for X with integral type with precision of one. */
1649 lookup_logical_inverted_value (tree name)
1652 enum tree_code code;
1655 /* If name has none-intergal type, or isn't a SSA_NAME, then
1657 if (TREE_CODE (name) != SSA_NAME
1658 || !INTEGRAL_TYPE_P (TREE_TYPE (name)))
1660 def = SSA_NAME_DEF_STMT (name);
1661 if (!is_gimple_assign (def))
1664 code = gimple_assign_rhs_code (def);
1665 op1 = gimple_assign_rhs1 (def);
1668 /* Get for EQ_EXPR or BIT_XOR_EXPR operation the second operand.
1669 If CODE isn't an EQ_EXPR, BIT_XOR_EXPR, or BIT_NOT_EXPR, then return. */
1670 if (code == EQ_EXPR || code == NE_EXPR
1671 || code == BIT_XOR_EXPR)
1672 op2 = gimple_assign_rhs2 (def);
1677 if (truth_valued_ssa_name (name))
1681 /* Check if we have X == 0 and X has an integral type. */
1682 if (!INTEGRAL_TYPE_P (TREE_TYPE (op1)))
1684 if (integer_zerop (op2))
1688 /* Check if we have X != 1 and X is a truth-valued. */
1689 if (!INTEGRAL_TYPE_P (TREE_TYPE (op1)))
1691 if (integer_onep (op2) && truth_valued_ssa_name (op1))
1695 /* Check if we have X ^ 1 and X is truth valued. */
1696 if (integer_onep (op2) && truth_valued_ssa_name (op1))
1706 /* Optimize ARG1 CODE ARG2 to a constant for bitwise binary
1707 operations CODE, if one operand has the logically inverted
1708 value of the other. */
1710 simplify_bitwise_binary_1 (enum tree_code code, tree type,
1711 tree arg1, tree arg2)
1715 /* If CODE isn't a bitwise binary operation, return NULL_TREE. */
1716 if (code != BIT_AND_EXPR && code != BIT_IOR_EXPR
1717 && code != BIT_XOR_EXPR)
1720 /* First check if operands ARG1 and ARG2 are equal. If so
1721 return NULL_TREE as this optimization is handled fold_stmt. */
1724 /* See if we have in arguments logical-not patterns. */
1725 if (((anot = lookup_logical_inverted_value (arg1)) == NULL_TREE
1727 && ((anot = lookup_logical_inverted_value (arg2)) == NULL_TREE
1732 if (code == BIT_AND_EXPR)
1733 return fold_convert (type, integer_zero_node);
1734 /* X | !X -> 1 and X ^ !X -> 1, if X is truth-valued. */
1735 if (truth_valued_ssa_name (anot))
1736 return fold_convert (type, integer_one_node);
1738 /* ??? Otherwise result is (X != 0 ? X : 1). not handled. */
1742 /* Simplify bitwise binary operations.
1743 Return true if a transformation applied, otherwise return false. */
1746 simplify_bitwise_binary (gimple_stmt_iterator *gsi)
1748 gimple stmt = gsi_stmt (*gsi);
1749 tree arg1 = gimple_assign_rhs1 (stmt);
1750 tree arg2 = gimple_assign_rhs2 (stmt);
1751 enum tree_code code = gimple_assign_rhs_code (stmt);
1753 gimple def1 = NULL, def2 = NULL;
1754 tree def1_arg1, def2_arg1;
1755 enum tree_code def1_code, def2_code;
1757 def1_code = TREE_CODE (arg1);
1759 if (TREE_CODE (arg1) == SSA_NAME)
1761 def1 = SSA_NAME_DEF_STMT (arg1);
1762 if (is_gimple_assign (def1))
1764 def1_code = gimple_assign_rhs_code (def1);
1765 def1_arg1 = gimple_assign_rhs1 (def1);
1769 def2_code = TREE_CODE (arg2);
1771 if (TREE_CODE (arg2) == SSA_NAME)
1773 def2 = SSA_NAME_DEF_STMT (arg2);
1774 if (is_gimple_assign (def2))
1776 def2_code = gimple_assign_rhs_code (def2);
1777 def2_arg1 = gimple_assign_rhs1 (def2);
1781 /* Try to fold (type) X op CST -> (type) (X op ((type-x) CST)). */
1782 if (TREE_CODE (arg2) == INTEGER_CST
1783 && CONVERT_EXPR_CODE_P (def1_code)
1784 && INTEGRAL_TYPE_P (TREE_TYPE (def1_arg1))
1785 && int_fits_type_p (arg2, TREE_TYPE (def1_arg1)))
1788 tree tem = create_tmp_reg (TREE_TYPE (def1_arg1), NULL);
1790 gimple_build_assign_with_ops (code, tem, def1_arg1,
1791 fold_convert_loc (gimple_location (stmt),
1792 TREE_TYPE (def1_arg1),
1794 tem = make_ssa_name (tem, newop);
1795 gimple_assign_set_lhs (newop, tem);
1796 gimple_set_location (newop, gimple_location (stmt));
1797 gsi_insert_before (gsi, newop, GSI_SAME_STMT);
1798 gimple_assign_set_rhs_with_ops_1 (gsi, NOP_EXPR,
1799 tem, NULL_TREE, NULL_TREE);
1800 update_stmt (gsi_stmt (*gsi));
1804 /* For bitwise binary operations apply operand conversions to the
1805 binary operation result instead of to the operands. This allows
1806 to combine successive conversions and bitwise binary operations. */
1807 if (CONVERT_EXPR_CODE_P (def1_code)
1808 && CONVERT_EXPR_CODE_P (def2_code)
1809 && types_compatible_p (TREE_TYPE (def1_arg1), TREE_TYPE (def2_arg1))
1810 /* Make sure that the conversion widens the operands, or has same
1811 precision, or that it changes the operation to a bitfield
1813 && ((TYPE_PRECISION (TREE_TYPE (def1_arg1))
1814 <= TYPE_PRECISION (TREE_TYPE (arg1)))
1815 || (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (arg1)))
1817 || (TYPE_PRECISION (TREE_TYPE (arg1))
1818 != GET_MODE_PRECISION (TYPE_MODE (TREE_TYPE (arg1))))))
1821 tree tem = create_tmp_reg (TREE_TYPE (def1_arg1),
1823 newop = gimple_build_assign_with_ops (code, tem, def1_arg1, def2_arg1);
1824 tem = make_ssa_name (tem, newop);
1825 gimple_assign_set_lhs (newop, tem);
1826 gimple_set_location (newop, gimple_location (stmt));
1827 gsi_insert_before (gsi, newop, GSI_SAME_STMT);
1828 gimple_assign_set_rhs_with_ops_1 (gsi, NOP_EXPR,
1829 tem, NULL_TREE, NULL_TREE);
1830 update_stmt (gsi_stmt (*gsi));
1834 /* (a | CST1) & CST2 -> (a & CST2) | (CST1 & CST2). */
1835 if (code == BIT_AND_EXPR
1836 && def1_code == BIT_IOR_EXPR
1837 && TREE_CODE (arg2) == INTEGER_CST
1838 && TREE_CODE (gimple_assign_rhs2 (def1)) == INTEGER_CST)
1840 tree cst = fold_build2 (BIT_AND_EXPR, TREE_TYPE (arg2),
1841 arg2, gimple_assign_rhs2 (def1));
1844 if (integer_zerop (cst))
1846 gimple_assign_set_rhs1 (stmt, def1_arg1);
1850 tem = create_tmp_reg (TREE_TYPE (arg2), NULL);
1851 newop = gimple_build_assign_with_ops (BIT_AND_EXPR,
1852 tem, def1_arg1, arg2);
1853 tem = make_ssa_name (tem, newop);
1854 gimple_assign_set_lhs (newop, tem);
1855 gimple_set_location (newop, gimple_location (stmt));
1856 /* Make sure to re-process the new stmt as it's walking upwards. */
1857 gsi_insert_before (gsi, newop, GSI_NEW_STMT);
1858 gimple_assign_set_rhs1 (stmt, tem);
1859 gimple_assign_set_rhs2 (stmt, cst);
1860 gimple_assign_set_rhs_code (stmt, BIT_IOR_EXPR);
1865 /* Combine successive equal operations with constants. */
1866 if ((code == BIT_AND_EXPR
1867 || code == BIT_IOR_EXPR
1868 || code == BIT_XOR_EXPR)
1869 && def1_code == code
1870 && TREE_CODE (arg2) == INTEGER_CST
1871 && TREE_CODE (gimple_assign_rhs2 (def1)) == INTEGER_CST)
1873 tree cst = fold_build2 (code, TREE_TYPE (arg2),
1874 arg2, gimple_assign_rhs2 (def1));
1875 gimple_assign_set_rhs1 (stmt, def1_arg1);
1876 gimple_assign_set_rhs2 (stmt, cst);
1881 /* Canonicalize X ^ ~0 to ~X. */
1882 if (code == BIT_XOR_EXPR
1883 && TREE_CODE (arg2) == INTEGER_CST
1884 && integer_all_onesp (arg2))
1886 gimple_assign_set_rhs_with_ops (gsi, BIT_NOT_EXPR, arg1, NULL_TREE);
1887 gcc_assert (gsi_stmt (*gsi) == stmt);
1892 /* Try simple folding for X op !X, and X op X. */
1893 res = simplify_bitwise_binary_1 (code, TREE_TYPE (arg1), arg1, arg2);
1894 if (res != NULL_TREE)
1896 gimple_assign_set_rhs_from_tree (gsi, res);
1897 update_stmt (gsi_stmt (*gsi));
1905 /* Perform re-associations of the plus or minus statement STMT that are
1906 always permitted. Returns true if the CFG was changed. */
1909 associate_plusminus (gimple stmt)
1911 tree rhs1 = gimple_assign_rhs1 (stmt);
1912 tree rhs2 = gimple_assign_rhs2 (stmt);
1913 enum tree_code code = gimple_assign_rhs_code (stmt);
1914 gimple_stmt_iterator gsi;
1917 /* We can't reassociate at all for saturating types. */
1918 if (TYPE_SATURATING (TREE_TYPE (rhs1)))
1921 /* First contract negates. */
1926 /* A +- (-B) -> A -+ B. */
1927 if (TREE_CODE (rhs2) == SSA_NAME)
1929 gimple def_stmt = SSA_NAME_DEF_STMT (rhs2);
1930 if (is_gimple_assign (def_stmt)
1931 && gimple_assign_rhs_code (def_stmt) == NEGATE_EXPR
1932 && can_propagate_from (def_stmt))
1934 code = (code == MINUS_EXPR) ? PLUS_EXPR : MINUS_EXPR;
1935 gimple_assign_set_rhs_code (stmt, code);
1936 rhs2 = gimple_assign_rhs1 (def_stmt);
1937 gimple_assign_set_rhs2 (stmt, rhs2);
1938 gimple_set_modified (stmt, true);
1943 /* (-A) + B -> B - A. */
1944 if (TREE_CODE (rhs1) == SSA_NAME
1945 && code == PLUS_EXPR)
1947 gimple def_stmt = SSA_NAME_DEF_STMT (rhs1);
1948 if (is_gimple_assign (def_stmt)
1949 && gimple_assign_rhs_code (def_stmt) == NEGATE_EXPR
1950 && can_propagate_from (def_stmt))
1953 gimple_assign_set_rhs_code (stmt, code);
1955 gimple_assign_set_rhs1 (stmt, rhs1);
1956 rhs2 = gimple_assign_rhs1 (def_stmt);
1957 gimple_assign_set_rhs2 (stmt, rhs2);
1958 gimple_set_modified (stmt, true);
1965 /* We can't reassociate floating-point or fixed-point plus or minus
1966 because of saturation to +-Inf. */
1967 if (FLOAT_TYPE_P (TREE_TYPE (rhs1))
1968 || FIXED_POINT_TYPE_P (TREE_TYPE (rhs1)))
1971 /* Second match patterns that allow contracting a plus-minus pair
1972 irrespective of overflow issues.
1974 (A +- B) - A -> +- B
1976 (CST +- A) +- CST -> CST +- A
1977 (A + CST) +- CST -> A + CST
1980 A - (A +- B) -> -+ B
1981 A +- (B +- A) -> +- B
1982 CST +- (CST +- A) -> CST +- A
1983 CST +- (A +- CST) -> CST +- A
1986 via commutating the addition and contracting operations to zero
1987 by reassociation. */
1989 gsi = gsi_for_stmt (stmt);
1990 if (TREE_CODE (rhs1) == SSA_NAME)
1992 gimple def_stmt = SSA_NAME_DEF_STMT (rhs1);
1993 if (is_gimple_assign (def_stmt) && can_propagate_from (def_stmt))
1995 enum tree_code def_code = gimple_assign_rhs_code (def_stmt);
1996 if (def_code == PLUS_EXPR
1997 || def_code == MINUS_EXPR)
1999 tree def_rhs1 = gimple_assign_rhs1 (def_stmt);
2000 tree def_rhs2 = gimple_assign_rhs2 (def_stmt);
2001 if (operand_equal_p (def_rhs1, rhs2, 0)
2002 && code == MINUS_EXPR)
2004 /* (A +- B) - A -> +- B. */
2005 code = ((def_code == PLUS_EXPR)
2006 ? TREE_CODE (def_rhs2) : NEGATE_EXPR);
2009 gimple_assign_set_rhs_with_ops (&gsi, code, rhs1, NULL_TREE);
2010 gcc_assert (gsi_stmt (gsi) == stmt);
2011 gimple_set_modified (stmt, true);
2013 else if (operand_equal_p (def_rhs2, rhs2, 0)
2014 && code != def_code)
2016 /* (A +- B) -+ B -> A. */
2017 code = TREE_CODE (def_rhs1);
2020 gimple_assign_set_rhs_with_ops (&gsi, code, rhs1, NULL_TREE);
2021 gcc_assert (gsi_stmt (gsi) == stmt);
2022 gimple_set_modified (stmt, true);
2024 else if (TREE_CODE (rhs2) == INTEGER_CST
2025 && TREE_CODE (def_rhs1) == INTEGER_CST)
2027 /* (CST +- A) +- CST -> CST +- A. */
2028 tree cst = fold_binary (code, TREE_TYPE (rhs1),
2030 if (cst && !TREE_OVERFLOW (cst))
2033 gimple_assign_set_rhs_code (stmt, code);
2035 gimple_assign_set_rhs1 (stmt, rhs1);
2037 gimple_assign_set_rhs2 (stmt, rhs2);
2038 gimple_set_modified (stmt, true);
2041 else if (TREE_CODE (rhs2) == INTEGER_CST
2042 && TREE_CODE (def_rhs2) == INTEGER_CST
2043 && def_code == PLUS_EXPR)
2045 /* (A + CST) +- CST -> A + CST. */
2046 tree cst = fold_binary (code, TREE_TYPE (rhs1),
2048 if (cst && !TREE_OVERFLOW (cst))
2051 gimple_assign_set_rhs_code (stmt, code);
2053 gimple_assign_set_rhs1 (stmt, rhs1);
2055 gimple_assign_set_rhs2 (stmt, rhs2);
2056 gimple_set_modified (stmt, true);
2060 else if (def_code == BIT_NOT_EXPR
2061 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
2063 tree def_rhs1 = gimple_assign_rhs1 (def_stmt);
2064 if (code == PLUS_EXPR
2065 && operand_equal_p (def_rhs1, rhs2, 0))
2069 rhs1 = build_int_cst_type (TREE_TYPE (rhs2), -1);
2071 gimple_assign_set_rhs_with_ops (&gsi, code, rhs1, NULL_TREE);
2072 gcc_assert (gsi_stmt (gsi) == stmt);
2073 gimple_set_modified (stmt, true);
2075 else if (code == PLUS_EXPR
2076 && integer_onep (rhs1))
2082 gimple_assign_set_rhs_with_ops (&gsi, code, rhs1, NULL_TREE);
2083 gcc_assert (gsi_stmt (gsi) == stmt);
2084 gimple_set_modified (stmt, true);
2090 if (rhs2 && TREE_CODE (rhs2) == SSA_NAME)
2092 gimple def_stmt = SSA_NAME_DEF_STMT (rhs2);
2093 if (is_gimple_assign (def_stmt) && can_propagate_from (def_stmt))
2095 enum tree_code def_code = gimple_assign_rhs_code (def_stmt);
2096 if (def_code == PLUS_EXPR
2097 || def_code == MINUS_EXPR)
2099 tree def_rhs1 = gimple_assign_rhs1 (def_stmt);
2100 tree def_rhs2 = gimple_assign_rhs2 (def_stmt);
2101 if (operand_equal_p (def_rhs1, rhs1, 0)
2102 && code == MINUS_EXPR)
2104 /* A - (A +- B) -> -+ B. */
2105 code = ((def_code == PLUS_EXPR)
2106 ? NEGATE_EXPR : TREE_CODE (def_rhs2));
2109 gimple_assign_set_rhs_with_ops (&gsi, code, rhs1, NULL_TREE);
2110 gcc_assert (gsi_stmt (gsi) == stmt);
2111 gimple_set_modified (stmt, true);
2113 else if (operand_equal_p (def_rhs2, rhs1, 0)
2114 && code != def_code)
2116 /* A +- (B +- A) -> +- B. */
2117 code = ((code == PLUS_EXPR)
2118 ? TREE_CODE (def_rhs1) : NEGATE_EXPR);
2121 gimple_assign_set_rhs_with_ops (&gsi, code, rhs1, NULL_TREE);
2122 gcc_assert (gsi_stmt (gsi) == stmt);
2123 gimple_set_modified (stmt, true);
2125 else if (TREE_CODE (rhs1) == INTEGER_CST
2126 && TREE_CODE (def_rhs1) == INTEGER_CST)
2128 /* CST +- (CST +- A) -> CST +- A. */
2129 tree cst = fold_binary (code, TREE_TYPE (rhs2),
2131 if (cst && !TREE_OVERFLOW (cst))
2133 code = (code == def_code ? PLUS_EXPR : MINUS_EXPR);
2134 gimple_assign_set_rhs_code (stmt, code);
2136 gimple_assign_set_rhs1 (stmt, rhs1);
2138 gimple_assign_set_rhs2 (stmt, rhs2);
2139 gimple_set_modified (stmt, true);
2142 else if (TREE_CODE (rhs1) == INTEGER_CST
2143 && TREE_CODE (def_rhs2) == INTEGER_CST)
2145 /* CST +- (A +- CST) -> CST +- A. */
2146 tree cst = fold_binary (def_code == code
2147 ? PLUS_EXPR : MINUS_EXPR,
2150 if (cst && !TREE_OVERFLOW (cst))
2153 gimple_assign_set_rhs1 (stmt, rhs1);
2155 gimple_assign_set_rhs2 (stmt, rhs2);
2156 gimple_set_modified (stmt, true);
2160 else if (def_code == BIT_NOT_EXPR
2161 && INTEGRAL_TYPE_P (TREE_TYPE (rhs2)))
2163 tree def_rhs1 = gimple_assign_rhs1 (def_stmt);
2164 if (code == PLUS_EXPR
2165 && operand_equal_p (def_rhs1, rhs1, 0))
2169 rhs1 = build_int_cst_type (TREE_TYPE (rhs1), -1);
2171 gimple_assign_set_rhs_with_ops (&gsi, code, rhs1, NULL_TREE);
2172 gcc_assert (gsi_stmt (gsi) == stmt);
2173 gimple_set_modified (stmt, true);
2180 if (gimple_modified_p (stmt))
2182 fold_stmt_inplace (stmt);
2184 if (maybe_clean_or_replace_eh_stmt (stmt, stmt)
2185 && gimple_purge_dead_eh_edges (gimple_bb (stmt)))
2192 /* Combine two conversions in a row for the second conversion at *GSI.
2193 Returns 1 if there were any changes made, 2 if cfg-cleanup needs to
2194 run. Else it returns 0. */
2197 combine_conversions (gimple_stmt_iterator *gsi)
2199 gimple stmt = gsi_stmt (*gsi);
2202 enum tree_code code = gimple_assign_rhs_code (stmt);
2204 gcc_checking_assert (CONVERT_EXPR_CODE_P (code)
2205 || code == FLOAT_EXPR
2206 || code == FIX_TRUNC_EXPR);
2208 lhs = gimple_assign_lhs (stmt);
2209 op0 = gimple_assign_rhs1 (stmt);
2210 if (useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (op0)))
2212 gimple_assign_set_rhs_code (stmt, TREE_CODE (op0));
2216 if (TREE_CODE (op0) != SSA_NAME)
2219 def_stmt = SSA_NAME_DEF_STMT (op0);
2220 if (!is_gimple_assign (def_stmt))
2223 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)))
2225 tree defop0 = gimple_assign_rhs1 (def_stmt);
2226 tree type = TREE_TYPE (lhs);
2227 tree inside_type = TREE_TYPE (defop0);
2228 tree inter_type = TREE_TYPE (op0);
2229 int inside_int = INTEGRAL_TYPE_P (inside_type);
2230 int inside_ptr = POINTER_TYPE_P (inside_type);
2231 int inside_float = FLOAT_TYPE_P (inside_type);
2232 int inside_vec = TREE_CODE (inside_type) == VECTOR_TYPE;
2233 unsigned int inside_prec = TYPE_PRECISION (inside_type);
2234 int inside_unsignedp = TYPE_UNSIGNED (inside_type);
2235 int inter_int = INTEGRAL_TYPE_P (inter_type);
2236 int inter_ptr = POINTER_TYPE_P (inter_type);
2237 int inter_float = FLOAT_TYPE_P (inter_type);
2238 int inter_vec = TREE_CODE (inter_type) == VECTOR_TYPE;
2239 unsigned int inter_prec = TYPE_PRECISION (inter_type);
2240 int inter_unsignedp = TYPE_UNSIGNED (inter_type);
2241 int final_int = INTEGRAL_TYPE_P (type);
2242 int final_ptr = POINTER_TYPE_P (type);
2243 int final_float = FLOAT_TYPE_P (type);
2244 int final_vec = TREE_CODE (type) == VECTOR_TYPE;
2245 unsigned int final_prec = TYPE_PRECISION (type);
2246 int final_unsignedp = TYPE_UNSIGNED (type);
2248 /* In addition to the cases of two conversions in a row
2249 handled below, if we are converting something to its own
2250 type via an object of identical or wider precision, neither
2251 conversion is needed. */
2252 if (useless_type_conversion_p (type, inside_type)
2253 && (((inter_int || inter_ptr) && final_int)
2254 || (inter_float && final_float))
2255 && inter_prec >= final_prec)
2257 gimple_assign_set_rhs1 (stmt, unshare_expr (defop0));
2258 gimple_assign_set_rhs_code (stmt, TREE_CODE (defop0));
2260 return remove_prop_source_from_use (op0) ? 2 : 1;
2263 /* Likewise, if the intermediate and initial types are either both
2264 float or both integer, we don't need the middle conversion if the
2265 former is wider than the latter and doesn't change the signedness
2266 (for integers). Avoid this if the final type is a pointer since
2267 then we sometimes need the middle conversion. Likewise if the
2268 final type has a precision not equal to the size of its mode. */
2269 if (((inter_int && inside_int)
2270 || (inter_float && inside_float)
2271 || (inter_vec && inside_vec))
2272 && inter_prec >= inside_prec
2273 && (inter_float || inter_vec
2274 || inter_unsignedp == inside_unsignedp)
2275 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (type))
2276 && TYPE_MODE (type) == TYPE_MODE (inter_type))
2278 && (! final_vec || inter_prec == inside_prec))
2280 gimple_assign_set_rhs1 (stmt, defop0);
2282 return remove_prop_source_from_use (op0) ? 2 : 1;
2285 /* If we have a sign-extension of a zero-extended value, we can
2286 replace that by a single zero-extension. */
2287 if (inside_int && inter_int && final_int
2288 && inside_prec < inter_prec && inter_prec < final_prec
2289 && inside_unsignedp && !inter_unsignedp)
2291 gimple_assign_set_rhs1 (stmt, defop0);
2293 return remove_prop_source_from_use (op0) ? 2 : 1;
2296 /* Two conversions in a row are not needed unless:
2297 - some conversion is floating-point (overstrict for now), or
2298 - some conversion is a vector (overstrict for now), or
2299 - the intermediate type is narrower than both initial and
2301 - the intermediate type and innermost type differ in signedness,
2302 and the outermost type is wider than the intermediate, or
2303 - the initial type is a pointer type and the precisions of the
2304 intermediate and final types differ, or
2305 - the final type is a pointer type and the precisions of the
2306 initial and intermediate types differ. */
2307 if (! inside_float && ! inter_float && ! final_float
2308 && ! inside_vec && ! inter_vec && ! final_vec
2309 && (inter_prec >= inside_prec || inter_prec >= final_prec)
2310 && ! (inside_int && inter_int
2311 && inter_unsignedp != inside_unsignedp
2312 && inter_prec < final_prec)
2313 && ((inter_unsignedp && inter_prec > inside_prec)
2314 == (final_unsignedp && final_prec > inter_prec))
2315 && ! (inside_ptr && inter_prec != final_prec)
2316 && ! (final_ptr && inside_prec != inter_prec)
2317 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (type))
2318 && TYPE_MODE (type) == TYPE_MODE (inter_type)))
2320 gimple_assign_set_rhs1 (stmt, defop0);
2322 return remove_prop_source_from_use (op0) ? 2 : 1;
2325 /* A truncation to an unsigned type should be canonicalized as
2326 bitwise and of a mask. */
2327 if (final_int && inter_int && inside_int
2328 && final_prec == inside_prec
2329 && final_prec > inter_prec
2333 tem = fold_build2 (BIT_AND_EXPR, inside_type,
2336 (inside_type, double_int_mask (inter_prec)));
2337 if (!useless_type_conversion_p (type, inside_type))
2339 tem = force_gimple_operand_gsi (gsi, tem, true, NULL_TREE, true,
2341 gimple_assign_set_rhs1 (stmt, tem);
2344 gimple_assign_set_rhs_from_tree (gsi, tem);
2345 update_stmt (gsi_stmt (*gsi));
2353 /* Main entry point for the forward propagation and statement combine
2357 ssa_forward_propagate_and_combine (void)
2360 unsigned int todoflags = 0;
2362 cfg_changed = false;
2366 gimple_stmt_iterator gsi, prev;
2367 bool prev_initialized;
2369 /* Apply forward propagation to all stmts in the basic-block.
2370 Note we update GSI within the loop as necessary. */
2371 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); )
2373 gimple stmt = gsi_stmt (gsi);
2375 enum tree_code code;
2377 if (!is_gimple_assign (stmt))
2383 lhs = gimple_assign_lhs (stmt);
2384 rhs = gimple_assign_rhs1 (stmt);
2385 code = gimple_assign_rhs_code (stmt);
2386 if (TREE_CODE (lhs) != SSA_NAME
2387 || has_zero_uses (lhs))
2393 /* If this statement sets an SSA_NAME to an address,
2394 try to propagate the address into the uses of the SSA_NAME. */
2395 if (code == ADDR_EXPR
2396 /* Handle pointer conversions on invariant addresses
2397 as well, as this is valid gimple. */
2398 || (CONVERT_EXPR_CODE_P (code)
2399 && TREE_CODE (rhs) == ADDR_EXPR
2400 && POINTER_TYPE_P (TREE_TYPE (lhs))))
2402 tree base = get_base_address (TREE_OPERAND (rhs, 0));
2405 || decl_address_invariant_p (base))
2406 && !stmt_references_abnormal_ssa_name (stmt)
2407 && forward_propagate_addr_expr (lhs, rhs))
2409 release_defs (stmt);
2410 todoflags |= TODO_remove_unused_locals;
2411 gsi_remove (&gsi, true);
2416 else if (code == POINTER_PLUS_EXPR)
2418 tree off = gimple_assign_rhs2 (stmt);
2419 if (TREE_CODE (off) == INTEGER_CST
2420 && can_propagate_from (stmt)
2421 && !simple_iv_increment_p (stmt)
2422 /* ??? Better adjust the interface to that function
2423 instead of building new trees here. */
2424 && forward_propagate_addr_expr
2426 build1_loc (gimple_location (stmt),
2427 ADDR_EXPR, TREE_TYPE (rhs),
2428 fold_build2 (MEM_REF,
2429 TREE_TYPE (TREE_TYPE (rhs)),
2431 fold_convert (ptr_type_node,
2434 release_defs (stmt);
2435 todoflags |= TODO_remove_unused_locals;
2436 gsi_remove (&gsi, true);
2438 else if (is_gimple_min_invariant (rhs))
2440 /* Make sure to fold &a[0] + off_1 here. */
2441 fold_stmt_inplace (stmt);
2443 if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR)
2449 else if (TREE_CODE_CLASS (code) == tcc_comparison)
2451 if (forward_propagate_comparison (stmt))
2459 /* Combine stmts with the stmts defining their operands.
2460 Note we update GSI within the loop as necessary. */
2461 prev_initialized = false;
2462 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi);)
2464 gimple stmt = gsi_stmt (gsi);
2465 bool changed = false;
2467 switch (gimple_code (stmt))
2471 tree rhs1 = gimple_assign_rhs1 (stmt);
2472 enum tree_code code = gimple_assign_rhs_code (stmt);
2474 if ((code == BIT_NOT_EXPR
2475 || code == NEGATE_EXPR)
2476 && TREE_CODE (rhs1) == SSA_NAME)
2477 changed = simplify_not_neg_expr (&gsi);
2478 else if (code == COND_EXPR)
2480 /* In this case the entire COND_EXPR is in rhs1. */
2481 changed |= forward_propagate_into_cond (&gsi);
2482 stmt = gsi_stmt (gsi);
2484 else if (TREE_CODE_CLASS (code) == tcc_comparison)
2487 did_something = forward_propagate_into_comparison (&gsi);
2488 if (did_something == 2)
2490 changed = did_something != 0;
2492 else if (code == BIT_AND_EXPR
2493 || code == BIT_IOR_EXPR
2494 || code == BIT_XOR_EXPR)
2495 changed = simplify_bitwise_binary (&gsi);
2496 else if (code == PLUS_EXPR
2497 || code == MINUS_EXPR)
2498 changed = associate_plusminus (stmt);
2499 else if (CONVERT_EXPR_CODE_P (code)
2500 || code == FLOAT_EXPR
2501 || code == FIX_TRUNC_EXPR)
2503 int did_something = combine_conversions (&gsi);
2504 if (did_something == 2)
2506 changed = did_something != 0;
2512 changed = simplify_gimple_switch (stmt);
2518 did_something = forward_propagate_into_gimple_cond (stmt);
2519 if (did_something == 2)
2521 changed = did_something != 0;
2527 tree callee = gimple_call_fndecl (stmt);
2528 if (callee != NULL_TREE
2529 && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
2530 changed = simplify_builtin_call (&gsi, callee);
2539 /* If the stmt changed then re-visit it and the statements
2540 inserted before it. */
2541 if (!prev_initialized)
2542 gsi = gsi_start_bb (bb);
2552 prev_initialized = true;
2559 todoflags |= TODO_cleanup_cfg;
2566 gate_forwprop (void)
2568 return flag_tree_forwprop;
2571 struct gimple_opt_pass pass_forwprop =
2575 "forwprop", /* name */
2576 gate_forwprop, /* gate */
2577 ssa_forward_propagate_and_combine, /* execute */
2580 0, /* static_pass_number */
2581 TV_TREE_FORWPROP, /* tv_id */
2582 PROP_cfg | PROP_ssa, /* properties_required */
2583 0, /* properties_provided */
2584 0, /* properties_destroyed */
2585 0, /* todo_flags_start */
2588 | TODO_verify_ssa /* todo_flags_finish */