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 type
= TREE_TYPE (gimple_assign_lhs (stmt
));
469 tree rhs1
= gimple_assign_rhs1 (stmt
);
470 tree rhs2
= gimple_assign_rhs2 (stmt
);
472 /* Combine the comparison with defining statements. */
473 tmp
= forward_propagate_into_comparison_1 (stmt
,
474 gimple_assign_rhs_code (stmt
),
476 if (tmp
&& useless_type_conversion_p (type
, TREE_TYPE (tmp
)))
478 gimple_assign_set_rhs_from_tree (gsi
, tmp
);
480 update_stmt (gsi_stmt (*gsi
));
482 if (TREE_CODE (rhs1
) == SSA_NAME
)
483 cfg_changed
|= remove_prop_source_from_use (rhs1
);
484 if (TREE_CODE (rhs2
) == SSA_NAME
)
485 cfg_changed
|= remove_prop_source_from_use (rhs2
);
486 return cfg_changed
? 2 : 1;
492 /* Propagate from the ssa name definition statements of COND_EXPR
493 in GIMPLE_COND statement STMT into the conditional if that simplifies it.
494 Returns zero if no statement was changed, one if there were
495 changes and two if cfg_cleanup needs to run.
497 This must be kept in sync with forward_propagate_into_cond. */
500 forward_propagate_into_gimple_cond (gimple stmt
)
503 enum tree_code code
= gimple_cond_code (stmt
);
504 bool cfg_changed
= false;
505 tree rhs1
= gimple_cond_lhs (stmt
);
506 tree rhs2
= gimple_cond_rhs (stmt
);
508 /* We can do tree combining on SSA_NAME and comparison expressions. */
509 if (TREE_CODE_CLASS (gimple_cond_code (stmt
)) != tcc_comparison
)
512 tmp
= forward_propagate_into_comparison_1 (stmt
, code
,
517 if (dump_file
&& tmp
)
519 fprintf (dump_file
, " Replaced '");
520 print_gimple_expr (dump_file
, stmt
, 0, 0);
521 fprintf (dump_file
, "' with '");
522 print_generic_expr (dump_file
, tmp
, 0);
523 fprintf (dump_file
, "'\n");
526 gimple_cond_set_condition_from_tree (stmt
, unshare_expr (tmp
));
529 if (TREE_CODE (rhs1
) == SSA_NAME
)
530 cfg_changed
|= remove_prop_source_from_use (rhs1
);
531 if (TREE_CODE (rhs2
) == SSA_NAME
)
532 cfg_changed
|= remove_prop_source_from_use (rhs2
);
533 return (cfg_changed
|| is_gimple_min_invariant (tmp
)) ? 2 : 1;
536 /* Canonicalize _Bool == 0 and _Bool != 1 to _Bool != 0 by swapping edges. */
537 if ((TREE_CODE (TREE_TYPE (rhs1
)) == BOOLEAN_TYPE
538 || (INTEGRAL_TYPE_P (TREE_TYPE (rhs1
))
539 && TYPE_PRECISION (TREE_TYPE (rhs1
)) == 1))
541 && integer_zerop (rhs2
))
543 && integer_onep (rhs2
))))
545 basic_block bb
= gimple_bb (stmt
);
546 gimple_cond_set_code (stmt
, NE_EXPR
);
547 gimple_cond_set_rhs (stmt
, build_zero_cst (TREE_TYPE (rhs1
)));
548 EDGE_SUCC (bb
, 0)->flags
^= (EDGE_TRUE_VALUE
|EDGE_FALSE_VALUE
);
549 EDGE_SUCC (bb
, 1)->flags
^= (EDGE_TRUE_VALUE
|EDGE_FALSE_VALUE
);
557 /* Propagate from the ssa name definition statements of COND_EXPR
558 in the rhs of statement STMT into the conditional if that simplifies it.
559 Returns true zero if the stmt was changed. */
562 forward_propagate_into_cond (gimple_stmt_iterator
*gsi_p
)
564 gimple stmt
= gsi_stmt (*gsi_p
);
565 tree tmp
= NULL_TREE
;
566 tree cond
= gimple_assign_rhs1 (stmt
);
569 /* We can do tree combining on SSA_NAME and comparison expressions. */
570 if (COMPARISON_CLASS_P (cond
))
571 tmp
= forward_propagate_into_comparison_1 (stmt
, TREE_CODE (cond
),
573 TREE_OPERAND (cond
, 0),
574 TREE_OPERAND (cond
, 1));
575 else if (TREE_CODE (cond
) == SSA_NAME
)
579 gimple def_stmt
= get_prop_source_stmt (name
, true, NULL
);
580 if (!def_stmt
|| !can_propagate_from (def_stmt
))
583 code
= gimple_assign_rhs_code (def_stmt
);
584 if (TREE_CODE_CLASS (code
) == tcc_comparison
)
585 tmp
= fold_build2_loc (gimple_location (def_stmt
),
588 gimple_assign_rhs1 (def_stmt
),
589 gimple_assign_rhs2 (def_stmt
));
590 else if ((code
== BIT_NOT_EXPR
591 && TYPE_PRECISION (TREE_TYPE (cond
)) == 1)
592 || (code
== BIT_XOR_EXPR
593 && integer_onep (gimple_assign_rhs2 (def_stmt
))))
595 tmp
= gimple_assign_rhs1 (def_stmt
);
601 && is_gimple_condexpr (tmp
))
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
, new_lhs
;
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_SIDE_EFFECTS (*def_rhs_basep
) = TREE_SIDE_EFFECTS (lhs
);
933 TREE_THIS_NOTRAP (*def_rhs_basep
) = TREE_THIS_NOTRAP (lhs
);
934 new_lhs
= unshare_expr (TREE_OPERAND (def_rhs
, 0));
935 gimple_assign_set_lhs (use_stmt
, new_lhs
);
936 TREE_THIS_VOLATILE (new_lhs
) = TREE_THIS_VOLATILE (lhs
);
937 TREE_SIDE_EFFECTS (new_lhs
) = TREE_SIDE_EFFECTS (lhs
);
938 *def_rhs_basep
= saved
;
939 tidy_after_forward_propagate_addr (use_stmt
);
940 /* Continue propagating into the RHS if this was not the
946 /* We can have a struct assignment dereferencing our name twice.
947 Note that we didn't propagate into the lhs to not falsely
948 claim we did when propagating into the rhs. */
952 /* Strip away any outer COMPONENT_REF, ARRAY_REF or ADDR_EXPR
953 nodes from the RHS. */
954 rhs
= gimple_assign_rhs1 (use_stmt
);
955 if (TREE_CODE (rhs
) == ADDR_EXPR
)
956 rhs
= TREE_OPERAND (rhs
, 0);
957 while (handled_component_p (rhs
))
958 rhs
= TREE_OPERAND (rhs
, 0);
960 /* Now see if the RHS node is a MEM_REF using NAME. If so,
961 propagate the ADDR_EXPR into the use of NAME and fold the result. */
962 if (TREE_CODE (rhs
) == MEM_REF
963 && TREE_OPERAND (rhs
, 0) == name
)
966 HOST_WIDE_INT def_rhs_offset
;
967 if ((def_rhs_base
= get_addr_base_and_unit_offset (TREE_OPERAND (def_rhs
, 0),
970 double_int off
= mem_ref_offset (rhs
);
972 off
= double_int_add (off
,
973 shwi_to_double_int (def_rhs_offset
));
974 if (TREE_CODE (def_rhs_base
) == MEM_REF
)
976 off
= double_int_add (off
, mem_ref_offset (def_rhs_base
));
977 new_ptr
= TREE_OPERAND (def_rhs_base
, 0);
980 new_ptr
= build_fold_addr_expr (def_rhs_base
);
981 TREE_OPERAND (rhs
, 0) = new_ptr
;
982 TREE_OPERAND (rhs
, 1)
983 = double_int_to_tree (TREE_TYPE (TREE_OPERAND (rhs
, 1)), off
);
984 fold_stmt_inplace (use_stmt_gsi
);
985 tidy_after_forward_propagate_addr (use_stmt
);
988 /* If the RHS is a plain dereference and the value type is the same as
989 that of the pointed-to type of the address we can put the
990 dereferenced address on the RHS preserving the original alias-type. */
991 else if (gimple_assign_rhs1 (use_stmt
) == rhs
992 && useless_type_conversion_p
993 (TREE_TYPE (gimple_assign_lhs (use_stmt
)),
994 TREE_TYPE (TREE_OPERAND (def_rhs
, 0))))
996 tree
*def_rhs_basep
= &TREE_OPERAND (def_rhs
, 0);
997 tree new_offset
, new_base
, saved
, new_rhs
;
998 while (handled_component_p (*def_rhs_basep
))
999 def_rhs_basep
= &TREE_OPERAND (*def_rhs_basep
, 0);
1000 saved
= *def_rhs_basep
;
1001 if (TREE_CODE (*def_rhs_basep
) == MEM_REF
)
1003 new_base
= TREE_OPERAND (*def_rhs_basep
, 0);
1005 = int_const_binop (PLUS_EXPR
, TREE_OPERAND (rhs
, 1),
1006 TREE_OPERAND (*def_rhs_basep
, 1));
1010 new_base
= build_fold_addr_expr (*def_rhs_basep
);
1011 new_offset
= TREE_OPERAND (rhs
, 1);
1013 *def_rhs_basep
= build2 (MEM_REF
, TREE_TYPE (*def_rhs_basep
),
1014 new_base
, new_offset
);
1015 TREE_THIS_VOLATILE (*def_rhs_basep
) = TREE_THIS_VOLATILE (rhs
);
1016 TREE_SIDE_EFFECTS (*def_rhs_basep
) = TREE_SIDE_EFFECTS (rhs
);
1017 TREE_THIS_NOTRAP (*def_rhs_basep
) = TREE_THIS_NOTRAP (rhs
);
1018 new_rhs
= unshare_expr (TREE_OPERAND (def_rhs
, 0));
1019 gimple_assign_set_rhs1 (use_stmt
, new_rhs
);
1020 TREE_THIS_VOLATILE (new_rhs
) = TREE_THIS_VOLATILE (rhs
);
1021 TREE_SIDE_EFFECTS (new_rhs
) = TREE_SIDE_EFFECTS (rhs
);
1022 *def_rhs_basep
= saved
;
1023 fold_stmt_inplace (use_stmt_gsi
);
1024 tidy_after_forward_propagate_addr (use_stmt
);
1029 /* If the use of the ADDR_EXPR is not a POINTER_PLUS_EXPR, there
1030 is nothing to do. */
1031 if (gimple_assign_rhs_code (use_stmt
) != POINTER_PLUS_EXPR
1032 || gimple_assign_rhs1 (use_stmt
) != name
)
1035 /* The remaining cases are all for turning pointer arithmetic into
1036 array indexing. They only apply when we have the address of
1037 element zero in an array. If that is not the case then there
1038 is nothing to do. */
1039 array_ref
= TREE_OPERAND (def_rhs
, 0);
1040 if ((TREE_CODE (array_ref
) != ARRAY_REF
1041 || TREE_CODE (TREE_TYPE (TREE_OPERAND (array_ref
, 0))) != ARRAY_TYPE
1042 || TREE_CODE (TREE_OPERAND (array_ref
, 1)) != INTEGER_CST
)
1043 && TREE_CODE (TREE_TYPE (array_ref
)) != ARRAY_TYPE
)
1046 rhs2
= gimple_assign_rhs2 (use_stmt
);
1047 /* Optimize &x[C1] p+ C2 to &x p+ C3 with C3 = C1 * element_size + C2. */
1048 if (TREE_CODE (rhs2
) == INTEGER_CST
)
1050 tree new_rhs
= build1_loc (gimple_location (use_stmt
),
1051 ADDR_EXPR
, TREE_TYPE (def_rhs
),
1052 fold_build2 (MEM_REF
,
1053 TREE_TYPE (TREE_TYPE (def_rhs
)),
1054 unshare_expr (def_rhs
),
1055 fold_convert (ptr_type_node
,
1057 gimple_assign_set_rhs_from_tree (use_stmt_gsi
, new_rhs
);
1058 use_stmt
= gsi_stmt (*use_stmt_gsi
);
1059 update_stmt (use_stmt
);
1060 tidy_after_forward_propagate_addr (use_stmt
);
1064 /* Try to optimize &x[0] p+ OFFSET where OFFSET is defined by
1065 converting a multiplication of an index by the size of the
1066 array elements, then the result is converted into the proper
1067 type for the arithmetic. */
1068 if (TREE_CODE (rhs2
) == SSA_NAME
1069 && (TREE_CODE (array_ref
) != ARRAY_REF
1070 || integer_zerop (TREE_OPERAND (array_ref
, 1)))
1071 && useless_type_conversion_p (TREE_TYPE (name
), TREE_TYPE (def_rhs
))
1072 /* Avoid problems with IVopts creating PLUS_EXPRs with a
1073 different type than their operands. */
1074 && useless_type_conversion_p (TREE_TYPE (lhs
), TREE_TYPE (def_rhs
)))
1075 return forward_propagate_addr_into_variable_array_index (rhs2
, def_rhs
,
1080 /* STMT is a statement of the form SSA_NAME = ADDR_EXPR <whatever>.
1082 Try to forward propagate the ADDR_EXPR into all uses of the SSA_NAME.
1083 Often this will allow for removal of an ADDR_EXPR and INDIRECT_REF
1084 node or for recovery of array indexing from pointer arithmetic.
1085 Returns true, if all uses have been propagated into. */
1088 forward_propagate_addr_expr (tree name
, tree rhs
)
1090 int stmt_loop_depth
= gimple_bb (SSA_NAME_DEF_STMT (name
))->loop_depth
;
1091 imm_use_iterator iter
;
1094 bool single_use_p
= has_single_use (name
);
1096 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
, name
)
1101 /* If the use is not in a simple assignment statement, then
1102 there is nothing we can do. */
1103 if (gimple_code (use_stmt
) != GIMPLE_ASSIGN
)
1105 if (!is_gimple_debug (use_stmt
))
1110 /* If the use is in a deeper loop nest, then we do not want
1111 to propagate non-invariant ADDR_EXPRs into the loop as that
1112 is likely adding expression evaluations into the loop. */
1113 if (gimple_bb (use_stmt
)->loop_depth
> stmt_loop_depth
1114 && !is_gimple_min_invariant (rhs
))
1121 gimple_stmt_iterator gsi
= gsi_for_stmt (use_stmt
);
1122 result
= forward_propagate_addr_expr_1 (name
, rhs
, &gsi
,
1124 /* If the use has moved to a different statement adjust
1125 the update machinery for the old statement too. */
1126 if (use_stmt
!= gsi_stmt (gsi
))
1128 update_stmt (use_stmt
);
1129 use_stmt
= gsi_stmt (gsi
);
1132 update_stmt (use_stmt
);
1136 /* Remove intermediate now unused copy and conversion chains. */
1137 use_rhs
= gimple_assign_rhs1 (use_stmt
);
1139 && TREE_CODE (gimple_assign_lhs (use_stmt
)) == SSA_NAME
1140 && TREE_CODE (use_rhs
) == SSA_NAME
1141 && has_zero_uses (gimple_assign_lhs (use_stmt
)))
1143 gimple_stmt_iterator gsi
= gsi_for_stmt (use_stmt
);
1144 release_defs (use_stmt
);
1145 gsi_remove (&gsi
, true);
1149 return all
&& has_zero_uses (name
);
1153 /* Forward propagate the comparison defined in STMT like
1154 cond_1 = x CMP y to uses of the form
1158 Returns true if stmt is now unused. */
1161 forward_propagate_comparison (gimple stmt
)
1163 tree name
= gimple_assign_lhs (stmt
);
1165 tree tmp
= NULL_TREE
;
1166 gimple_stmt_iterator gsi
;
1167 enum tree_code code
;
1170 /* Don't propagate ssa names that occur in abnormal phis. */
1171 if ((TREE_CODE (gimple_assign_rhs1 (stmt
)) == SSA_NAME
1172 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_assign_rhs1 (stmt
)))
1173 || (TREE_CODE (gimple_assign_rhs2 (stmt
)) == SSA_NAME
1174 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_assign_rhs2 (stmt
))))
1177 /* Do not un-cse comparisons. But propagate through copies. */
1178 use_stmt
= get_prop_dest_stmt (name
, &name
);
1180 || !is_gimple_assign (use_stmt
))
1183 code
= gimple_assign_rhs_code (use_stmt
);
1184 lhs
= gimple_assign_lhs (use_stmt
);
1185 if (!INTEGRAL_TYPE_P (TREE_TYPE (lhs
)))
1188 /* We can propagate the condition into a statement that
1189 computes the logical negation of the comparison result. */
1190 if ((code
== BIT_NOT_EXPR
1191 && TYPE_PRECISION (TREE_TYPE (lhs
)) == 1)
1192 || (code
== BIT_XOR_EXPR
1193 && integer_onep (gimple_assign_rhs2 (use_stmt
))))
1195 tree type
= TREE_TYPE (gimple_assign_rhs1 (stmt
));
1196 bool nans
= HONOR_NANS (TYPE_MODE (type
));
1197 enum tree_code inv_code
;
1198 inv_code
= invert_tree_comparison (gimple_assign_rhs_code (stmt
), nans
);
1199 if (inv_code
== ERROR_MARK
)
1202 tmp
= build2 (inv_code
, TREE_TYPE (lhs
), gimple_assign_rhs1 (stmt
),
1203 gimple_assign_rhs2 (stmt
));
1208 gsi
= gsi_for_stmt (use_stmt
);
1209 gimple_assign_set_rhs_from_tree (&gsi
, unshare_expr (tmp
));
1210 use_stmt
= gsi_stmt (gsi
);
1211 update_stmt (use_stmt
);
1213 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1215 fprintf (dump_file
, " Replaced '");
1216 print_gimple_expr (dump_file
, stmt
, 0, dump_flags
);
1217 fprintf (dump_file
, "' with '");
1218 print_gimple_expr (dump_file
, use_stmt
, 0, dump_flags
);
1219 fprintf (dump_file
, "'\n");
1222 /* Remove defining statements. */
1223 return remove_prop_source_from_use (name
);
1227 /* If we have lhs = ~x (STMT), look and see if earlier we had x = ~y.
1228 If so, we can change STMT into lhs = y which can later be copy
1229 propagated. Similarly for negation.
1231 This could trivially be formulated as a forward propagation
1232 to immediate uses. However, we already had an implementation
1233 from DOM which used backward propagation via the use-def links.
1235 It turns out that backward propagation is actually faster as
1236 there's less work to do for each NOT/NEG expression we find.
1237 Backwards propagation needs to look at the statement in a single
1238 backlink. Forward propagation needs to look at potentially more
1239 than one forward link.
1241 Returns true when the statement was changed. */
1244 simplify_not_neg_expr (gimple_stmt_iterator
*gsi_p
)
1246 gimple stmt
= gsi_stmt (*gsi_p
);
1247 tree rhs
= gimple_assign_rhs1 (stmt
);
1248 gimple rhs_def_stmt
= SSA_NAME_DEF_STMT (rhs
);
1250 /* See if the RHS_DEF_STMT has the same form as our statement. */
1251 if (is_gimple_assign (rhs_def_stmt
)
1252 && gimple_assign_rhs_code (rhs_def_stmt
) == gimple_assign_rhs_code (stmt
))
1254 tree rhs_def_operand
= gimple_assign_rhs1 (rhs_def_stmt
);
1256 /* Verify that RHS_DEF_OPERAND is a suitable SSA_NAME. */
1257 if (TREE_CODE (rhs_def_operand
) == SSA_NAME
1258 && ! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs_def_operand
))
1260 gimple_assign_set_rhs_from_tree (gsi_p
, rhs_def_operand
);
1261 stmt
= gsi_stmt (*gsi_p
);
1270 /* STMT is a SWITCH_EXPR for which we attempt to find equivalent forms of
1271 the condition which we may be able to optimize better. */
1274 simplify_gimple_switch (gimple stmt
)
1276 tree cond
= gimple_switch_index (stmt
);
1280 /* The optimization that we really care about is removing unnecessary
1281 casts. That will let us do much better in propagating the inferred
1282 constant at the switch target. */
1283 if (TREE_CODE (cond
) == SSA_NAME
)
1285 def_stmt
= SSA_NAME_DEF_STMT (cond
);
1286 if (is_gimple_assign (def_stmt
))
1288 if (gimple_assign_rhs_code (def_stmt
) == NOP_EXPR
)
1293 def
= gimple_assign_rhs1 (def_stmt
);
1295 /* ??? Why was Jeff testing this? We are gimple... */
1296 gcc_checking_assert (is_gimple_val (def
));
1298 to
= TREE_TYPE (cond
);
1299 ti
= TREE_TYPE (def
);
1301 /* If we have an extension that preserves value, then we
1302 can copy the source value into the switch. */
1304 need_precision
= TYPE_PRECISION (ti
);
1306 if (! INTEGRAL_TYPE_P (ti
))
1308 else if (TYPE_UNSIGNED (to
) && !TYPE_UNSIGNED (ti
))
1310 else if (!TYPE_UNSIGNED (to
) && TYPE_UNSIGNED (ti
))
1311 need_precision
+= 1;
1312 if (TYPE_PRECISION (to
) < need_precision
)
1317 gimple_switch_set_index (stmt
, def
);
1328 /* For pointers p2 and p1 return p2 - p1 if the
1329 difference is known and constant, otherwise return NULL. */
1332 constant_pointer_difference (tree p1
, tree p2
)
1335 #define CPD_ITERATIONS 5
1336 tree exps
[2][CPD_ITERATIONS
];
1337 tree offs
[2][CPD_ITERATIONS
];
1340 for (i
= 0; i
< 2; i
++)
1342 tree p
= i
? p1
: p2
;
1343 tree off
= size_zero_node
;
1345 enum tree_code code
;
1347 /* For each of p1 and p2 we need to iterate at least
1348 twice, to handle ADDR_EXPR directly in p1/p2,
1349 SSA_NAME with ADDR_EXPR or POINTER_PLUS_EXPR etc.
1350 on definition's stmt RHS. Iterate a few extra times. */
1354 if (!POINTER_TYPE_P (TREE_TYPE (p
)))
1356 if (TREE_CODE (p
) == ADDR_EXPR
)
1358 tree q
= TREE_OPERAND (p
, 0);
1359 HOST_WIDE_INT offset
;
1360 tree base
= get_addr_base_and_unit_offset (q
, &offset
);
1365 off
= size_binop (PLUS_EXPR
, off
, size_int (offset
));
1367 if (TREE_CODE (q
) == MEM_REF
1368 && TREE_CODE (TREE_OPERAND (q
, 0)) == SSA_NAME
)
1370 p
= TREE_OPERAND (q
, 0);
1371 off
= size_binop (PLUS_EXPR
, off
,
1372 double_int_to_tree (sizetype
,
1373 mem_ref_offset (q
)));
1382 if (TREE_CODE (p
) != SSA_NAME
)
1386 if (j
== CPD_ITERATIONS
)
1388 stmt
= SSA_NAME_DEF_STMT (p
);
1389 if (!is_gimple_assign (stmt
) || gimple_assign_lhs (stmt
) != p
)
1391 code
= gimple_assign_rhs_code (stmt
);
1392 if (code
== POINTER_PLUS_EXPR
)
1394 if (TREE_CODE (gimple_assign_rhs2 (stmt
)) != INTEGER_CST
)
1396 off
= size_binop (PLUS_EXPR
, off
, gimple_assign_rhs2 (stmt
));
1397 p
= gimple_assign_rhs1 (stmt
);
1399 else if (code
== ADDR_EXPR
|| code
== NOP_EXPR
)
1400 p
= gimple_assign_rhs1 (stmt
);
1408 for (i
= 0; i
< cnt
[0]; i
++)
1409 for (j
= 0; j
< cnt
[1]; j
++)
1410 if (exps
[0][i
] == exps
[1][j
])
1411 return size_binop (MINUS_EXPR
, offs
[0][i
], offs
[1][j
]);
1416 /* *GSI_P is a GIMPLE_CALL to a builtin function.
1418 memcpy (p, "abcd", 4);
1419 memset (p + 4, ' ', 3);
1421 memcpy (p, "abcd ", 7);
1422 call if the latter can be stored by pieces during expansion. */
1425 simplify_builtin_call (gimple_stmt_iterator
*gsi_p
, tree callee2
)
1427 gimple stmt1
, stmt2
= gsi_stmt (*gsi_p
);
1428 tree vuse
= gimple_vuse (stmt2
);
1431 stmt1
= SSA_NAME_DEF_STMT (vuse
);
1433 switch (DECL_FUNCTION_CODE (callee2
))
1435 case BUILT_IN_MEMSET
:
1436 if (gimple_call_num_args (stmt2
) != 3
1437 || gimple_call_lhs (stmt2
)
1439 || BITS_PER_UNIT
!= 8)
1444 tree ptr1
, src1
, str1
, off1
, len1
, lhs1
;
1445 tree ptr2
= gimple_call_arg (stmt2
, 0);
1446 tree val2
= gimple_call_arg (stmt2
, 1);
1447 tree len2
= gimple_call_arg (stmt2
, 2);
1448 tree diff
, vdef
, new_str_cst
;
1450 unsigned int ptr1_align
;
1451 unsigned HOST_WIDE_INT src_len
;
1453 use_operand_p use_p
;
1455 if (!host_integerp (val2
, 0)
1456 || !host_integerp (len2
, 1))
1458 if (is_gimple_call (stmt1
))
1460 /* If first stmt is a call, it needs to be memcpy
1461 or mempcpy, with string literal as second argument and
1463 callee1
= gimple_call_fndecl (stmt1
);
1464 if (callee1
== NULL_TREE
1465 || DECL_BUILT_IN_CLASS (callee1
) != BUILT_IN_NORMAL
1466 || gimple_call_num_args (stmt1
) != 3)
1468 if (DECL_FUNCTION_CODE (callee1
) != BUILT_IN_MEMCPY
1469 && DECL_FUNCTION_CODE (callee1
) != BUILT_IN_MEMPCPY
)
1471 ptr1
= gimple_call_arg (stmt1
, 0);
1472 src1
= gimple_call_arg (stmt1
, 1);
1473 len1
= gimple_call_arg (stmt1
, 2);
1474 lhs1
= gimple_call_lhs (stmt1
);
1475 if (!host_integerp (len1
, 1))
1477 str1
= string_constant (src1
, &off1
);
1478 if (str1
== NULL_TREE
)
1480 if (!host_integerp (off1
, 1)
1481 || compare_tree_int (off1
, TREE_STRING_LENGTH (str1
) - 1) > 0
1482 || compare_tree_int (len1
, TREE_STRING_LENGTH (str1
)
1483 - tree_low_cst (off1
, 1)) > 0
1484 || TREE_CODE (TREE_TYPE (str1
)) != ARRAY_TYPE
1485 || TYPE_MODE (TREE_TYPE (TREE_TYPE (str1
)))
1486 != TYPE_MODE (char_type_node
))
1489 else if (gimple_assign_single_p (stmt1
))
1491 /* Otherwise look for length 1 memcpy optimized into
1493 ptr1
= gimple_assign_lhs (stmt1
);
1494 src1
= gimple_assign_rhs1 (stmt1
);
1495 if (TREE_CODE (ptr1
) != MEM_REF
1496 || TYPE_MODE (TREE_TYPE (ptr1
)) != TYPE_MODE (char_type_node
)
1497 || !host_integerp (src1
, 0))
1499 ptr1
= build_fold_addr_expr (ptr1
);
1500 callee1
= NULL_TREE
;
1501 len1
= size_one_node
;
1503 off1
= size_zero_node
;
1509 diff
= constant_pointer_difference (ptr1
, ptr2
);
1510 if (diff
== NULL
&& lhs1
!= NULL
)
1512 diff
= constant_pointer_difference (lhs1
, ptr2
);
1513 if (DECL_FUNCTION_CODE (callee1
) == BUILT_IN_MEMPCPY
1515 diff
= size_binop (PLUS_EXPR
, diff
,
1516 fold_convert (sizetype
, len1
));
1518 /* If the difference between the second and first destination pointer
1519 is not constant, or is bigger than memcpy length, bail out. */
1521 || !host_integerp (diff
, 1)
1522 || tree_int_cst_lt (len1
, diff
))
1525 /* Use maximum of difference plus memset length and memcpy length
1526 as the new memcpy length, if it is too big, bail out. */
1527 src_len
= tree_low_cst (diff
, 1);
1528 src_len
+= tree_low_cst (len2
, 1);
1529 if (src_len
< (unsigned HOST_WIDE_INT
) tree_low_cst (len1
, 1))
1530 src_len
= tree_low_cst (len1
, 1);
1534 /* If mempcpy value is used elsewhere, bail out, as mempcpy
1535 with bigger length will return different result. */
1536 if (lhs1
!= NULL_TREE
1537 && DECL_FUNCTION_CODE (callee1
) == BUILT_IN_MEMPCPY
1538 && (TREE_CODE (lhs1
) != SSA_NAME
1539 || !single_imm_use (lhs1
, &use_p
, &use_stmt
)
1540 || use_stmt
!= stmt2
))
1543 /* If anything reads memory in between memcpy and memset
1544 call, the modified memcpy call might change it. */
1545 vdef
= gimple_vdef (stmt1
);
1547 && (!single_imm_use (vdef
, &use_p
, &use_stmt
)
1548 || use_stmt
!= stmt2
))
1551 ptr1_align
= get_pointer_alignment (ptr1
);
1552 /* Construct the new source string literal. */
1553 src_buf
= XALLOCAVEC (char, src_len
+ 1);
1556 TREE_STRING_POINTER (str1
) + tree_low_cst (off1
, 1),
1557 tree_low_cst (len1
, 1));
1559 src_buf
[0] = tree_low_cst (src1
, 0);
1560 memset (src_buf
+ tree_low_cst (diff
, 1),
1561 tree_low_cst (val2
, 1), tree_low_cst (len2
, 1));
1562 src_buf
[src_len
] = '\0';
1563 /* Neither builtin_strncpy_read_str nor builtin_memcpy_read_str
1564 handle embedded '\0's. */
1565 if (strlen (src_buf
) != src_len
)
1567 rtl_profile_for_bb (gimple_bb (stmt2
));
1568 /* If the new memcpy wouldn't be emitted by storing the literal
1569 by pieces, this optimization might enlarge .rodata too much,
1570 as commonly used string literals couldn't be shared any
1572 if (!can_store_by_pieces (src_len
,
1573 builtin_strncpy_read_str
,
1574 src_buf
, ptr1_align
, false))
1577 new_str_cst
= build_string_literal (src_len
, src_buf
);
1580 /* If STMT1 is a mem{,p}cpy call, adjust it and remove
1582 if (lhs1
&& DECL_FUNCTION_CODE (callee1
) == BUILT_IN_MEMPCPY
)
1583 gimple_call_set_lhs (stmt1
, NULL_TREE
);
1584 gimple_call_set_arg (stmt1
, 1, new_str_cst
);
1585 gimple_call_set_arg (stmt1
, 2,
1586 build_int_cst (TREE_TYPE (len1
), src_len
));
1587 update_stmt (stmt1
);
1588 unlink_stmt_vdef (stmt2
);
1589 gsi_remove (gsi_p
, true);
1590 release_defs (stmt2
);
1591 if (lhs1
&& DECL_FUNCTION_CODE (callee1
) == BUILT_IN_MEMPCPY
)
1592 release_ssa_name (lhs1
);
1597 /* Otherwise, if STMT1 is length 1 memcpy optimized into
1598 assignment, remove STMT1 and change memset call into
1600 gimple_stmt_iterator gsi
= gsi_for_stmt (stmt1
);
1602 if (!is_gimple_val (ptr1
))
1603 ptr1
= force_gimple_operand_gsi (gsi_p
, ptr1
, true, NULL_TREE
,
1604 true, GSI_SAME_STMT
);
1605 gimple_call_set_fndecl (stmt2
,
1606 builtin_decl_explicit (BUILT_IN_MEMCPY
));
1607 gimple_call_set_arg (stmt2
, 0, ptr1
);
1608 gimple_call_set_arg (stmt2
, 1, new_str_cst
);
1609 gimple_call_set_arg (stmt2
, 2,
1610 build_int_cst (TREE_TYPE (len2
), src_len
));
1611 unlink_stmt_vdef (stmt1
);
1612 gsi_remove (&gsi
, true);
1613 release_defs (stmt1
);
1614 update_stmt (stmt2
);
1625 /* Checks if expression has type of one-bit precision, or is a known
1626 truth-valued expression. */
1628 truth_valued_ssa_name (tree name
)
1631 tree type
= TREE_TYPE (name
);
1633 if (!INTEGRAL_TYPE_P (type
))
1635 /* Don't check here for BOOLEAN_TYPE as the precision isn't
1636 necessarily one and so ~X is not equal to !X. */
1637 if (TYPE_PRECISION (type
) == 1)
1639 def
= SSA_NAME_DEF_STMT (name
);
1640 if (is_gimple_assign (def
))
1641 return truth_value_p (gimple_assign_rhs_code (def
));
1645 /* Helper routine for simplify_bitwise_binary_1 function.
1646 Return for the SSA name NAME the expression X if it mets condition
1647 NAME = !X. Otherwise return NULL_TREE.
1648 Detected patterns for NAME = !X are:
1649 !X and X == 0 for X with integral type.
1650 X ^ 1, X != 1,or ~X for X with integral type with precision of one. */
1652 lookup_logical_inverted_value (tree name
)
1655 enum tree_code code
;
1658 /* If name has none-intergal type, or isn't a SSA_NAME, then
1660 if (TREE_CODE (name
) != SSA_NAME
1661 || !INTEGRAL_TYPE_P (TREE_TYPE (name
)))
1663 def
= SSA_NAME_DEF_STMT (name
);
1664 if (!is_gimple_assign (def
))
1667 code
= gimple_assign_rhs_code (def
);
1668 op1
= gimple_assign_rhs1 (def
);
1671 /* Get for EQ_EXPR or BIT_XOR_EXPR operation the second operand.
1672 If CODE isn't an EQ_EXPR, BIT_XOR_EXPR, or BIT_NOT_EXPR, then return. */
1673 if (code
== EQ_EXPR
|| code
== NE_EXPR
1674 || code
== BIT_XOR_EXPR
)
1675 op2
= gimple_assign_rhs2 (def
);
1680 if (truth_valued_ssa_name (name
))
1684 /* Check if we have X == 0 and X has an integral type. */
1685 if (!INTEGRAL_TYPE_P (TREE_TYPE (op1
)))
1687 if (integer_zerop (op2
))
1691 /* Check if we have X != 1 and X is a truth-valued. */
1692 if (!INTEGRAL_TYPE_P (TREE_TYPE (op1
)))
1694 if (integer_onep (op2
) && truth_valued_ssa_name (op1
))
1698 /* Check if we have X ^ 1 and X is truth valued. */
1699 if (integer_onep (op2
) && truth_valued_ssa_name (op1
))
1709 /* Optimize ARG1 CODE ARG2 to a constant for bitwise binary
1710 operations CODE, if one operand has the logically inverted
1711 value of the other. */
1713 simplify_bitwise_binary_1 (enum tree_code code
, tree type
,
1714 tree arg1
, tree arg2
)
1718 /* If CODE isn't a bitwise binary operation, return NULL_TREE. */
1719 if (code
!= BIT_AND_EXPR
&& code
!= BIT_IOR_EXPR
1720 && code
!= BIT_XOR_EXPR
)
1723 /* First check if operands ARG1 and ARG2 are equal. If so
1724 return NULL_TREE as this optimization is handled fold_stmt. */
1727 /* See if we have in arguments logical-not patterns. */
1728 if (((anot
= lookup_logical_inverted_value (arg1
)) == NULL_TREE
1730 && ((anot
= lookup_logical_inverted_value (arg2
)) == NULL_TREE
1735 if (code
== BIT_AND_EXPR
)
1736 return fold_convert (type
, integer_zero_node
);
1737 /* X | !X -> 1 and X ^ !X -> 1, if X is truth-valued. */
1738 if (truth_valued_ssa_name (anot
))
1739 return fold_convert (type
, integer_one_node
);
1741 /* ??? Otherwise result is (X != 0 ? X : 1). not handled. */
1745 /* Simplify bitwise binary operations.
1746 Return true if a transformation applied, otherwise return false. */
1749 simplify_bitwise_binary (gimple_stmt_iterator
*gsi
)
1751 gimple stmt
= gsi_stmt (*gsi
);
1752 tree arg1
= gimple_assign_rhs1 (stmt
);
1753 tree arg2
= gimple_assign_rhs2 (stmt
);
1754 enum tree_code code
= gimple_assign_rhs_code (stmt
);
1756 gimple def1
= NULL
, def2
= NULL
;
1757 tree def1_arg1
, def2_arg1
;
1758 enum tree_code def1_code
, def2_code
;
1760 def1_code
= TREE_CODE (arg1
);
1762 if (TREE_CODE (arg1
) == SSA_NAME
)
1764 def1
= SSA_NAME_DEF_STMT (arg1
);
1765 if (is_gimple_assign (def1
))
1767 def1_code
= gimple_assign_rhs_code (def1
);
1768 def1_arg1
= gimple_assign_rhs1 (def1
);
1772 def2_code
= TREE_CODE (arg2
);
1774 if (TREE_CODE (arg2
) == SSA_NAME
)
1776 def2
= SSA_NAME_DEF_STMT (arg2
);
1777 if (is_gimple_assign (def2
))
1779 def2_code
= gimple_assign_rhs_code (def2
);
1780 def2_arg1
= gimple_assign_rhs1 (def2
);
1784 /* Try to fold (type) X op CST -> (type) (X op ((type-x) CST)). */
1785 if (TREE_CODE (arg2
) == INTEGER_CST
1786 && CONVERT_EXPR_CODE_P (def1_code
)
1787 && INTEGRAL_TYPE_P (TREE_TYPE (def1_arg1
))
1788 && int_fits_type_p (arg2
, TREE_TYPE (def1_arg1
)))
1791 tree tem
= create_tmp_reg (TREE_TYPE (def1_arg1
), NULL
);
1793 gimple_build_assign_with_ops (code
, tem
, def1_arg1
,
1794 fold_convert_loc (gimple_location (stmt
),
1795 TREE_TYPE (def1_arg1
),
1797 tem
= make_ssa_name (tem
, newop
);
1798 gimple_assign_set_lhs (newop
, tem
);
1799 gimple_set_location (newop
, gimple_location (stmt
));
1800 gsi_insert_before (gsi
, newop
, GSI_SAME_STMT
);
1801 gimple_assign_set_rhs_with_ops_1 (gsi
, NOP_EXPR
,
1802 tem
, NULL_TREE
, NULL_TREE
);
1803 update_stmt (gsi_stmt (*gsi
));
1807 /* For bitwise binary operations apply operand conversions to the
1808 binary operation result instead of to the operands. This allows
1809 to combine successive conversions and bitwise binary operations. */
1810 if (CONVERT_EXPR_CODE_P (def1_code
)
1811 && CONVERT_EXPR_CODE_P (def2_code
)
1812 && types_compatible_p (TREE_TYPE (def1_arg1
), TREE_TYPE (def2_arg1
))
1813 /* Make sure that the conversion widens the operands, or has same
1814 precision, or that it changes the operation to a bitfield
1816 && ((TYPE_PRECISION (TREE_TYPE (def1_arg1
))
1817 <= TYPE_PRECISION (TREE_TYPE (arg1
)))
1818 || (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (arg1
)))
1820 || (TYPE_PRECISION (TREE_TYPE (arg1
))
1821 != GET_MODE_PRECISION (TYPE_MODE (TREE_TYPE (arg1
))))))
1824 tree tem
= create_tmp_reg (TREE_TYPE (def1_arg1
),
1826 newop
= gimple_build_assign_with_ops (code
, tem
, def1_arg1
, def2_arg1
);
1827 tem
= make_ssa_name (tem
, newop
);
1828 gimple_assign_set_lhs (newop
, tem
);
1829 gimple_set_location (newop
, gimple_location (stmt
));
1830 gsi_insert_before (gsi
, newop
, GSI_SAME_STMT
);
1831 gimple_assign_set_rhs_with_ops_1 (gsi
, NOP_EXPR
,
1832 tem
, NULL_TREE
, NULL_TREE
);
1833 update_stmt (gsi_stmt (*gsi
));
1837 /* (a | CST1) & CST2 -> (a & CST2) | (CST1 & CST2). */
1838 if (code
== BIT_AND_EXPR
1839 && def1_code
== BIT_IOR_EXPR
1840 && TREE_CODE (arg2
) == INTEGER_CST
1841 && TREE_CODE (gimple_assign_rhs2 (def1
)) == INTEGER_CST
)
1843 tree cst
= fold_build2 (BIT_AND_EXPR
, TREE_TYPE (arg2
),
1844 arg2
, gimple_assign_rhs2 (def1
));
1847 if (integer_zerop (cst
))
1849 gimple_assign_set_rhs1 (stmt
, def1_arg1
);
1853 tem
= create_tmp_reg (TREE_TYPE (arg2
), NULL
);
1854 newop
= gimple_build_assign_with_ops (BIT_AND_EXPR
,
1855 tem
, def1_arg1
, arg2
);
1856 tem
= make_ssa_name (tem
, newop
);
1857 gimple_assign_set_lhs (newop
, tem
);
1858 gimple_set_location (newop
, gimple_location (stmt
));
1859 /* Make sure to re-process the new stmt as it's walking upwards. */
1860 gsi_insert_before (gsi
, newop
, GSI_NEW_STMT
);
1861 gimple_assign_set_rhs1 (stmt
, tem
);
1862 gimple_assign_set_rhs2 (stmt
, cst
);
1863 gimple_assign_set_rhs_code (stmt
, BIT_IOR_EXPR
);
1868 /* Combine successive equal operations with constants. */
1869 if ((code
== BIT_AND_EXPR
1870 || code
== BIT_IOR_EXPR
1871 || code
== BIT_XOR_EXPR
)
1872 && def1_code
== code
1873 && TREE_CODE (arg2
) == INTEGER_CST
1874 && TREE_CODE (gimple_assign_rhs2 (def1
)) == INTEGER_CST
)
1876 tree cst
= fold_build2 (code
, TREE_TYPE (arg2
),
1877 arg2
, gimple_assign_rhs2 (def1
));
1878 gimple_assign_set_rhs1 (stmt
, def1_arg1
);
1879 gimple_assign_set_rhs2 (stmt
, cst
);
1884 /* Canonicalize X ^ ~0 to ~X. */
1885 if (code
== BIT_XOR_EXPR
1886 && TREE_CODE (arg2
) == INTEGER_CST
1887 && integer_all_onesp (arg2
))
1889 gimple_assign_set_rhs_with_ops (gsi
, BIT_NOT_EXPR
, arg1
, NULL_TREE
);
1890 gcc_assert (gsi_stmt (*gsi
) == stmt
);
1895 /* Try simple folding for X op !X, and X op X. */
1896 res
= simplify_bitwise_binary_1 (code
, TREE_TYPE (arg1
), arg1
, arg2
);
1897 if (res
!= NULL_TREE
)
1899 gimple_assign_set_rhs_from_tree (gsi
, res
);
1900 update_stmt (gsi_stmt (*gsi
));
1908 /* Perform re-associations of the plus or minus statement STMT that are
1909 always permitted. Returns true if the CFG was changed. */
1912 associate_plusminus (gimple_stmt_iterator
*gsi
)
1914 gimple stmt
= gsi_stmt (*gsi
);
1915 tree rhs1
= gimple_assign_rhs1 (stmt
);
1916 tree rhs2
= gimple_assign_rhs2 (stmt
);
1917 enum tree_code code
= gimple_assign_rhs_code (stmt
);
1920 /* We can't reassociate at all for saturating types. */
1921 if (TYPE_SATURATING (TREE_TYPE (rhs1
)))
1924 /* First contract negates. */
1929 /* A +- (-B) -> A -+ B. */
1930 if (TREE_CODE (rhs2
) == SSA_NAME
)
1932 gimple def_stmt
= SSA_NAME_DEF_STMT (rhs2
);
1933 if (is_gimple_assign (def_stmt
)
1934 && gimple_assign_rhs_code (def_stmt
) == NEGATE_EXPR
1935 && can_propagate_from (def_stmt
))
1937 code
= (code
== MINUS_EXPR
) ? PLUS_EXPR
: MINUS_EXPR
;
1938 gimple_assign_set_rhs_code (stmt
, code
);
1939 rhs2
= gimple_assign_rhs1 (def_stmt
);
1940 gimple_assign_set_rhs2 (stmt
, rhs2
);
1941 gimple_set_modified (stmt
, true);
1946 /* (-A) + B -> B - A. */
1947 if (TREE_CODE (rhs1
) == SSA_NAME
1948 && code
== PLUS_EXPR
)
1950 gimple def_stmt
= SSA_NAME_DEF_STMT (rhs1
);
1951 if (is_gimple_assign (def_stmt
)
1952 && gimple_assign_rhs_code (def_stmt
) == NEGATE_EXPR
1953 && can_propagate_from (def_stmt
))
1956 gimple_assign_set_rhs_code (stmt
, code
);
1958 gimple_assign_set_rhs1 (stmt
, rhs1
);
1959 rhs2
= gimple_assign_rhs1 (def_stmt
);
1960 gimple_assign_set_rhs2 (stmt
, rhs2
);
1961 gimple_set_modified (stmt
, true);
1968 /* We can't reassociate floating-point or fixed-point plus or minus
1969 because of saturation to +-Inf. */
1970 if (FLOAT_TYPE_P (TREE_TYPE (rhs1
))
1971 || FIXED_POINT_TYPE_P (TREE_TYPE (rhs1
)))
1974 /* Second match patterns that allow contracting a plus-minus pair
1975 irrespective of overflow issues.
1977 (A +- B) - A -> +- B
1979 (CST +- A) +- CST -> CST +- A
1980 (A + CST) +- CST -> A + CST
1983 A - (A +- B) -> -+ B
1984 A +- (B +- A) -> +- B
1985 CST +- (CST +- A) -> CST +- A
1986 CST +- (A +- CST) -> CST +- A
1989 via commutating the addition and contracting operations to zero
1990 by reassociation. */
1992 if (TREE_CODE (rhs1
) == SSA_NAME
)
1994 gimple def_stmt
= SSA_NAME_DEF_STMT (rhs1
);
1995 if (is_gimple_assign (def_stmt
) && can_propagate_from (def_stmt
))
1997 enum tree_code def_code
= gimple_assign_rhs_code (def_stmt
);
1998 if (def_code
== PLUS_EXPR
1999 || def_code
== MINUS_EXPR
)
2001 tree def_rhs1
= gimple_assign_rhs1 (def_stmt
);
2002 tree def_rhs2
= gimple_assign_rhs2 (def_stmt
);
2003 if (operand_equal_p (def_rhs1
, rhs2
, 0)
2004 && code
== MINUS_EXPR
)
2006 /* (A +- B) - A -> +- B. */
2007 code
= ((def_code
== PLUS_EXPR
)
2008 ? TREE_CODE (def_rhs2
) : NEGATE_EXPR
);
2011 gimple_assign_set_rhs_with_ops (gsi
, code
, rhs1
, NULL_TREE
);
2012 gcc_assert (gsi_stmt (*gsi
) == stmt
);
2013 gimple_set_modified (stmt
, true);
2015 else if (operand_equal_p (def_rhs2
, rhs2
, 0)
2016 && code
!= def_code
)
2018 /* (A +- B) -+ B -> A. */
2019 code
= TREE_CODE (def_rhs1
);
2022 gimple_assign_set_rhs_with_ops (gsi
, code
, rhs1
, NULL_TREE
);
2023 gcc_assert (gsi_stmt (*gsi
) == stmt
);
2024 gimple_set_modified (stmt
, true);
2026 else if (TREE_CODE (rhs2
) == INTEGER_CST
2027 && TREE_CODE (def_rhs1
) == INTEGER_CST
)
2029 /* (CST +- A) +- CST -> CST +- A. */
2030 tree cst
= fold_binary (code
, TREE_TYPE (rhs1
),
2032 if (cst
&& !TREE_OVERFLOW (cst
))
2035 gimple_assign_set_rhs_code (stmt
, code
);
2037 gimple_assign_set_rhs1 (stmt
, rhs1
);
2039 gimple_assign_set_rhs2 (stmt
, rhs2
);
2040 gimple_set_modified (stmt
, true);
2043 else if (TREE_CODE (rhs2
) == INTEGER_CST
2044 && TREE_CODE (def_rhs2
) == INTEGER_CST
2045 && def_code
== PLUS_EXPR
)
2047 /* (A + CST) +- CST -> A + CST. */
2048 tree cst
= fold_binary (code
, TREE_TYPE (rhs1
),
2050 if (cst
&& !TREE_OVERFLOW (cst
))
2053 gimple_assign_set_rhs_code (stmt
, code
);
2055 gimple_assign_set_rhs1 (stmt
, rhs1
);
2057 gimple_assign_set_rhs2 (stmt
, rhs2
);
2058 gimple_set_modified (stmt
, true);
2062 else if (def_code
== BIT_NOT_EXPR
2063 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1
)))
2065 tree def_rhs1
= gimple_assign_rhs1 (def_stmt
);
2066 if (code
== PLUS_EXPR
2067 && operand_equal_p (def_rhs1
, rhs2
, 0))
2071 rhs1
= build_int_cst_type (TREE_TYPE (rhs2
), -1);
2073 gimple_assign_set_rhs_with_ops (gsi
, code
, rhs1
, NULL_TREE
);
2074 gcc_assert (gsi_stmt (*gsi
) == stmt
);
2075 gimple_set_modified (stmt
, true);
2077 else if (code
== PLUS_EXPR
2078 && integer_onep (rhs1
))
2084 gimple_assign_set_rhs_with_ops (gsi
, code
, rhs1
, NULL_TREE
);
2085 gcc_assert (gsi_stmt (*gsi
) == stmt
);
2086 gimple_set_modified (stmt
, true);
2092 if (rhs2
&& TREE_CODE (rhs2
) == SSA_NAME
)
2094 gimple def_stmt
= SSA_NAME_DEF_STMT (rhs2
);
2095 if (is_gimple_assign (def_stmt
) && can_propagate_from (def_stmt
))
2097 enum tree_code def_code
= gimple_assign_rhs_code (def_stmt
);
2098 if (def_code
== PLUS_EXPR
2099 || def_code
== MINUS_EXPR
)
2101 tree def_rhs1
= gimple_assign_rhs1 (def_stmt
);
2102 tree def_rhs2
= gimple_assign_rhs2 (def_stmt
);
2103 if (operand_equal_p (def_rhs1
, rhs1
, 0)
2104 && code
== MINUS_EXPR
)
2106 /* A - (A +- B) -> -+ B. */
2107 code
= ((def_code
== PLUS_EXPR
)
2108 ? NEGATE_EXPR
: TREE_CODE (def_rhs2
));
2111 gimple_assign_set_rhs_with_ops (gsi
, code
, rhs1
, NULL_TREE
);
2112 gcc_assert (gsi_stmt (*gsi
) == stmt
);
2113 gimple_set_modified (stmt
, true);
2115 else if (operand_equal_p (def_rhs2
, rhs1
, 0)
2116 && code
!= def_code
)
2118 /* A +- (B +- A) -> +- B. */
2119 code
= ((code
== PLUS_EXPR
)
2120 ? TREE_CODE (def_rhs1
) : NEGATE_EXPR
);
2123 gimple_assign_set_rhs_with_ops (gsi
, code
, rhs1
, NULL_TREE
);
2124 gcc_assert (gsi_stmt (*gsi
) == stmt
);
2125 gimple_set_modified (stmt
, true);
2127 else if (TREE_CODE (rhs1
) == INTEGER_CST
2128 && TREE_CODE (def_rhs1
) == INTEGER_CST
)
2130 /* CST +- (CST +- A) -> CST +- A. */
2131 tree cst
= fold_binary (code
, TREE_TYPE (rhs2
),
2133 if (cst
&& !TREE_OVERFLOW (cst
))
2135 code
= (code
== def_code
? PLUS_EXPR
: MINUS_EXPR
);
2136 gimple_assign_set_rhs_code (stmt
, code
);
2138 gimple_assign_set_rhs1 (stmt
, rhs1
);
2140 gimple_assign_set_rhs2 (stmt
, rhs2
);
2141 gimple_set_modified (stmt
, true);
2144 else if (TREE_CODE (rhs1
) == INTEGER_CST
2145 && TREE_CODE (def_rhs2
) == INTEGER_CST
)
2147 /* CST +- (A +- CST) -> CST +- A. */
2148 tree cst
= fold_binary (def_code
== code
2149 ? PLUS_EXPR
: MINUS_EXPR
,
2152 if (cst
&& !TREE_OVERFLOW (cst
))
2155 gimple_assign_set_rhs1 (stmt
, rhs1
);
2157 gimple_assign_set_rhs2 (stmt
, rhs2
);
2158 gimple_set_modified (stmt
, true);
2162 else if (def_code
== BIT_NOT_EXPR
2163 && INTEGRAL_TYPE_P (TREE_TYPE (rhs2
)))
2165 tree def_rhs1
= gimple_assign_rhs1 (def_stmt
);
2166 if (code
== PLUS_EXPR
2167 && operand_equal_p (def_rhs1
, rhs1
, 0))
2171 rhs1
= build_int_cst_type (TREE_TYPE (rhs1
), -1);
2173 gimple_assign_set_rhs_with_ops (gsi
, code
, rhs1
, NULL_TREE
);
2174 gcc_assert (gsi_stmt (*gsi
) == stmt
);
2175 gimple_set_modified (stmt
, true);
2182 if (gimple_modified_p (stmt
))
2184 fold_stmt_inplace (gsi
);
2186 if (maybe_clean_or_replace_eh_stmt (stmt
, stmt
)
2187 && gimple_purge_dead_eh_edges (gimple_bb (stmt
)))
2194 /* Combine two conversions in a row for the second conversion at *GSI.
2195 Returns 1 if there were any changes made, 2 if cfg-cleanup needs to
2196 run. Else it returns 0. */
2199 combine_conversions (gimple_stmt_iterator
*gsi
)
2201 gimple stmt
= gsi_stmt (*gsi
);
2204 enum tree_code code
= gimple_assign_rhs_code (stmt
);
2206 gcc_checking_assert (CONVERT_EXPR_CODE_P (code
)
2207 || code
== FLOAT_EXPR
2208 || code
== FIX_TRUNC_EXPR
);
2210 lhs
= gimple_assign_lhs (stmt
);
2211 op0
= gimple_assign_rhs1 (stmt
);
2212 if (useless_type_conversion_p (TREE_TYPE (lhs
), TREE_TYPE (op0
)))
2214 gimple_assign_set_rhs_code (stmt
, TREE_CODE (op0
));
2218 if (TREE_CODE (op0
) != SSA_NAME
)
2221 def_stmt
= SSA_NAME_DEF_STMT (op0
);
2222 if (!is_gimple_assign (def_stmt
))
2225 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt
)))
2227 tree defop0
= gimple_assign_rhs1 (def_stmt
);
2228 tree type
= TREE_TYPE (lhs
);
2229 tree inside_type
= TREE_TYPE (defop0
);
2230 tree inter_type
= TREE_TYPE (op0
);
2231 int inside_int
= INTEGRAL_TYPE_P (inside_type
);
2232 int inside_ptr
= POINTER_TYPE_P (inside_type
);
2233 int inside_float
= FLOAT_TYPE_P (inside_type
);
2234 int inside_vec
= TREE_CODE (inside_type
) == VECTOR_TYPE
;
2235 unsigned int inside_prec
= TYPE_PRECISION (inside_type
);
2236 int inside_unsignedp
= TYPE_UNSIGNED (inside_type
);
2237 int inter_int
= INTEGRAL_TYPE_P (inter_type
);
2238 int inter_ptr
= POINTER_TYPE_P (inter_type
);
2239 int inter_float
= FLOAT_TYPE_P (inter_type
);
2240 int inter_vec
= TREE_CODE (inter_type
) == VECTOR_TYPE
;
2241 unsigned int inter_prec
= TYPE_PRECISION (inter_type
);
2242 int inter_unsignedp
= TYPE_UNSIGNED (inter_type
);
2243 int final_int
= INTEGRAL_TYPE_P (type
);
2244 int final_ptr
= POINTER_TYPE_P (type
);
2245 int final_float
= FLOAT_TYPE_P (type
);
2246 int final_vec
= TREE_CODE (type
) == VECTOR_TYPE
;
2247 unsigned int final_prec
= TYPE_PRECISION (type
);
2248 int final_unsignedp
= TYPE_UNSIGNED (type
);
2250 /* In addition to the cases of two conversions in a row
2251 handled below, if we are converting something to its own
2252 type via an object of identical or wider precision, neither
2253 conversion is needed. */
2254 if (useless_type_conversion_p (type
, inside_type
)
2255 && (((inter_int
|| inter_ptr
) && final_int
)
2256 || (inter_float
&& final_float
))
2257 && inter_prec
>= final_prec
)
2259 gimple_assign_set_rhs1 (stmt
, unshare_expr (defop0
));
2260 gimple_assign_set_rhs_code (stmt
, TREE_CODE (defop0
));
2262 return remove_prop_source_from_use (op0
) ? 2 : 1;
2265 /* Likewise, if the intermediate and initial types are either both
2266 float or both integer, we don't need the middle conversion if the
2267 former is wider than the latter and doesn't change the signedness
2268 (for integers). Avoid this if the final type is a pointer since
2269 then we sometimes need the middle conversion. Likewise if the
2270 final type has a precision not equal to the size of its mode. */
2271 if (((inter_int
&& inside_int
)
2272 || (inter_float
&& inside_float
)
2273 || (inter_vec
&& inside_vec
))
2274 && inter_prec
>= inside_prec
2275 && (inter_float
|| inter_vec
2276 || inter_unsignedp
== inside_unsignedp
)
2277 && ! (final_prec
!= GET_MODE_BITSIZE (TYPE_MODE (type
))
2278 && TYPE_MODE (type
) == TYPE_MODE (inter_type
))
2280 && (! final_vec
|| inter_prec
== inside_prec
))
2282 gimple_assign_set_rhs1 (stmt
, defop0
);
2284 return remove_prop_source_from_use (op0
) ? 2 : 1;
2287 /* If we have a sign-extension of a zero-extended value, we can
2288 replace that by a single zero-extension. */
2289 if (inside_int
&& inter_int
&& final_int
2290 && inside_prec
< inter_prec
&& inter_prec
< final_prec
2291 && inside_unsignedp
&& !inter_unsignedp
)
2293 gimple_assign_set_rhs1 (stmt
, defop0
);
2295 return remove_prop_source_from_use (op0
) ? 2 : 1;
2298 /* Two conversions in a row are not needed unless:
2299 - some conversion is floating-point (overstrict for now), or
2300 - some conversion is a vector (overstrict for now), or
2301 - the intermediate type is narrower than both initial and
2303 - the intermediate type and innermost type differ in signedness,
2304 and the outermost type is wider than the intermediate, or
2305 - the initial type is a pointer type and the precisions of the
2306 intermediate and final types differ, or
2307 - the final type is a pointer type and the precisions of the
2308 initial and intermediate types differ. */
2309 if (! inside_float
&& ! inter_float
&& ! final_float
2310 && ! inside_vec
&& ! inter_vec
&& ! final_vec
2311 && (inter_prec
>= inside_prec
|| inter_prec
>= final_prec
)
2312 && ! (inside_int
&& inter_int
2313 && inter_unsignedp
!= inside_unsignedp
2314 && inter_prec
< final_prec
)
2315 && ((inter_unsignedp
&& inter_prec
> inside_prec
)
2316 == (final_unsignedp
&& final_prec
> inter_prec
))
2317 && ! (inside_ptr
&& inter_prec
!= final_prec
)
2318 && ! (final_ptr
&& inside_prec
!= inter_prec
)
2319 && ! (final_prec
!= GET_MODE_BITSIZE (TYPE_MODE (type
))
2320 && TYPE_MODE (type
) == TYPE_MODE (inter_type
)))
2322 gimple_assign_set_rhs1 (stmt
, defop0
);
2324 return remove_prop_source_from_use (op0
) ? 2 : 1;
2327 /* A truncation to an unsigned type should be canonicalized as
2328 bitwise and of a mask. */
2329 if (final_int
&& inter_int
&& inside_int
2330 && final_prec
== inside_prec
2331 && final_prec
> inter_prec
2335 tem
= fold_build2 (BIT_AND_EXPR
, inside_type
,
2338 (inside_type
, double_int_mask (inter_prec
)));
2339 if (!useless_type_conversion_p (type
, inside_type
))
2341 tem
= force_gimple_operand_gsi (gsi
, tem
, true, NULL_TREE
, true,
2343 gimple_assign_set_rhs1 (stmt
, tem
);
2346 gimple_assign_set_rhs_from_tree (gsi
, tem
);
2347 update_stmt (gsi_stmt (*gsi
));
2355 /* Main entry point for the forward propagation and statement combine
2359 ssa_forward_propagate_and_combine (void)
2362 unsigned int todoflags
= 0;
2364 cfg_changed
= false;
2368 gimple_stmt_iterator gsi
, prev
;
2369 bool prev_initialized
;
2371 /* Apply forward propagation to all stmts in the basic-block.
2372 Note we update GSI within the loop as necessary. */
2373 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); )
2375 gimple stmt
= gsi_stmt (gsi
);
2377 enum tree_code code
;
2379 if (!is_gimple_assign (stmt
))
2385 lhs
= gimple_assign_lhs (stmt
);
2386 rhs
= gimple_assign_rhs1 (stmt
);
2387 code
= gimple_assign_rhs_code (stmt
);
2388 if (TREE_CODE (lhs
) != SSA_NAME
2389 || has_zero_uses (lhs
))
2395 /* If this statement sets an SSA_NAME to an address,
2396 try to propagate the address into the uses of the SSA_NAME. */
2397 if (code
== ADDR_EXPR
2398 /* Handle pointer conversions on invariant addresses
2399 as well, as this is valid gimple. */
2400 || (CONVERT_EXPR_CODE_P (code
)
2401 && TREE_CODE (rhs
) == ADDR_EXPR
2402 && POINTER_TYPE_P (TREE_TYPE (lhs
))))
2404 tree base
= get_base_address (TREE_OPERAND (rhs
, 0));
2407 || decl_address_invariant_p (base
))
2408 && !stmt_references_abnormal_ssa_name (stmt
)
2409 && forward_propagate_addr_expr (lhs
, rhs
))
2411 release_defs (stmt
);
2412 todoflags
|= TODO_remove_unused_locals
;
2413 gsi_remove (&gsi
, true);
2418 else if (code
== POINTER_PLUS_EXPR
)
2420 tree off
= gimple_assign_rhs2 (stmt
);
2421 if (TREE_CODE (off
) == INTEGER_CST
2422 && can_propagate_from (stmt
)
2423 && !simple_iv_increment_p (stmt
)
2424 /* ??? Better adjust the interface to that function
2425 instead of building new trees here. */
2426 && forward_propagate_addr_expr
2428 build1_loc (gimple_location (stmt
),
2429 ADDR_EXPR
, TREE_TYPE (rhs
),
2430 fold_build2 (MEM_REF
,
2431 TREE_TYPE (TREE_TYPE (rhs
)),
2433 fold_convert (ptr_type_node
,
2436 release_defs (stmt
);
2437 todoflags
|= TODO_remove_unused_locals
;
2438 gsi_remove (&gsi
, true);
2440 else if (is_gimple_min_invariant (rhs
))
2442 /* Make sure to fold &a[0] + off_1 here. */
2443 fold_stmt_inplace (&gsi
);
2445 if (gimple_assign_rhs_code (stmt
) == POINTER_PLUS_EXPR
)
2451 else if (TREE_CODE_CLASS (code
) == tcc_comparison
)
2453 if (forward_propagate_comparison (stmt
))
2461 /* Combine stmts with the stmts defining their operands.
2462 Note we update GSI within the loop as necessary. */
2463 prev_initialized
= false;
2464 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
);)
2466 gimple stmt
= gsi_stmt (gsi
);
2467 bool changed
= false;
2469 switch (gimple_code (stmt
))
2473 tree rhs1
= gimple_assign_rhs1 (stmt
);
2474 enum tree_code code
= gimple_assign_rhs_code (stmt
);
2476 if ((code
== BIT_NOT_EXPR
2477 || code
== NEGATE_EXPR
)
2478 && TREE_CODE (rhs1
) == SSA_NAME
)
2479 changed
= simplify_not_neg_expr (&gsi
);
2480 else if (code
== COND_EXPR
)
2482 /* In this case the entire COND_EXPR is in rhs1. */
2483 changed
|= forward_propagate_into_cond (&gsi
);
2484 stmt
= gsi_stmt (gsi
);
2486 else if (TREE_CODE_CLASS (code
) == tcc_comparison
)
2489 did_something
= forward_propagate_into_comparison (&gsi
);
2490 if (did_something
== 2)
2492 changed
= did_something
!= 0;
2494 else if (code
== BIT_AND_EXPR
2495 || code
== BIT_IOR_EXPR
2496 || code
== BIT_XOR_EXPR
)
2497 changed
= simplify_bitwise_binary (&gsi
);
2498 else if (code
== PLUS_EXPR
2499 || code
== MINUS_EXPR
)
2500 changed
= associate_plusminus (&gsi
);
2501 else if (CONVERT_EXPR_CODE_P (code
)
2502 || code
== FLOAT_EXPR
2503 || code
== FIX_TRUNC_EXPR
)
2505 int did_something
= combine_conversions (&gsi
);
2506 if (did_something
== 2)
2508 changed
= did_something
!= 0;
2514 changed
= simplify_gimple_switch (stmt
);
2520 did_something
= forward_propagate_into_gimple_cond (stmt
);
2521 if (did_something
== 2)
2523 changed
= did_something
!= 0;
2529 tree callee
= gimple_call_fndecl (stmt
);
2530 if (callee
!= NULL_TREE
2531 && DECL_BUILT_IN_CLASS (callee
) == BUILT_IN_NORMAL
)
2532 changed
= simplify_builtin_call (&gsi
, callee
);
2541 /* If the stmt changed then re-visit it and the statements
2542 inserted before it. */
2543 if (!prev_initialized
)
2544 gsi
= gsi_start_bb (bb
);
2554 prev_initialized
= true;
2561 todoflags
|= TODO_cleanup_cfg
;
2568 gate_forwprop (void)
2570 return flag_tree_forwprop
;
2573 struct gimple_opt_pass pass_forwprop
=
2577 "forwprop", /* name */
2578 gate_forwprop
, /* gate */
2579 ssa_forward_propagate_and_combine
, /* execute */
2582 0, /* static_pass_number */
2583 TV_TREE_FORWPROP
, /* tv_id */
2584 PROP_cfg
| PROP_ssa
, /* properties_required */
2585 0, /* properties_provided */
2586 0, /* properties_destroyed */
2587 0, /* todo_flags_start */
2590 | TODO_verify_ssa
/* todo_flags_finish */