1 /* Conditional constant propagation pass for the GNU compiler.
2 Copyright (C) 2000-2019 Free Software Foundation, Inc.
3 Adapted from original RTL SSA-CCP by Daniel Berlin <dberlin@dberlin.org>
4 Adapted to GIMPLE trees by Diego Novillo <dnovillo@redhat.com>
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it
9 under the terms of the GNU General Public License as published by the
10 Free Software Foundation; either version 3, or (at your option) any
13 GCC is distributed in the hope that it will be useful, but WITHOUT
14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Conditional constant propagation (CCP) is based on the SSA
23 propagation engine (tree-ssa-propagate.c). Constant assignments of
24 the form VAR = CST are propagated from the assignments into uses of
25 VAR, which in turn may generate new constants. The simulation uses
26 a four level lattice to keep track of constant values associated
27 with SSA names. Given an SSA name V_i, it may take one of the
30 UNINITIALIZED -> the initial state of the value. This value
31 is replaced with a correct initial value
32 the first time the value is used, so the
33 rest of the pass does not need to care about
34 it. Using this value simplifies initialization
35 of the pass, and prevents us from needlessly
36 scanning statements that are never reached.
38 UNDEFINED -> V_i is a local variable whose definition
39 has not been processed yet. Therefore we
40 don't yet know if its value is a constant
43 CONSTANT -> V_i has been found to hold a constant
46 VARYING -> V_i cannot take a constant value, or if it
47 does, it is not possible to determine it
50 The core of SSA-CCP is in ccp_visit_stmt and ccp_visit_phi_node:
52 1- In ccp_visit_stmt, we are interested in assignments whose RHS
53 evaluates into a constant and conditional jumps whose predicate
54 evaluates into a boolean true or false. When an assignment of
55 the form V_i = CONST is found, V_i's lattice value is set to
56 CONSTANT and CONST is associated with it. This causes the
57 propagation engine to add all the SSA edges coming out the
58 assignment into the worklists, so that statements that use V_i
61 If the statement is a conditional with a constant predicate, we
62 mark the outgoing edges as executable or not executable
63 depending on the predicate's value. This is then used when
64 visiting PHI nodes to know when a PHI argument can be ignored.
67 2- In ccp_visit_phi_node, if all the PHI arguments evaluate to the
68 same constant C, then the LHS of the PHI is set to C. This
69 evaluation is known as the "meet operation". Since one of the
70 goals of this evaluation is to optimistically return constant
71 values as often as possible, it uses two main short cuts:
73 - If an argument is flowing in through a non-executable edge, it
74 is ignored. This is useful in cases like this:
80 a_11 = PHI (a_9, a_10)
82 If PRED is known to always evaluate to false, then we can
83 assume that a_11 will always take its value from a_10, meaning
84 that instead of consider it VARYING (a_9 and a_10 have
85 different values), we can consider it CONSTANT 100.
87 - If an argument has an UNDEFINED value, then it does not affect
88 the outcome of the meet operation. If a variable V_i has an
89 UNDEFINED value, it means that either its defining statement
90 hasn't been visited yet or V_i has no defining statement, in
91 which case the original symbol 'V' is being used
92 uninitialized. Since 'V' is a local variable, the compiler
93 may assume any initial value for it.
96 After propagation, every variable V_i that ends up with a lattice
97 value of CONSTANT will have the associated constant value in the
98 array CONST_VAL[i].VALUE. That is fed into substitute_and_fold for
99 final substitution and folding.
101 This algorithm uses wide-ints at the max precision of the target.
102 This means that, with one uninteresting exception, variables with
103 UNSIGNED types never go to VARYING because the bits above the
104 precision of the type of the variable are always zero. The
105 uninteresting case is a variable of UNSIGNED type that has the
106 maximum precision of the target. Such variables can go to VARYING,
107 but this causes no loss of infomation since these variables will
112 Constant propagation with conditional branches,
113 Wegman and Zadeck, ACM TOPLAS 13(2):181-210.
115 Building an Optimizing Compiler,
116 Robert Morgan, Butterworth-Heinemann, 1998, Section 8.9.
118 Advanced Compiler Design and Implementation,
119 Steven Muchnick, Morgan Kaufmann, 1997, Section 12.6 */
123 #include "coretypes.h"
128 #include "tree-pass.h"
130 #include "gimple-pretty-print.h"
131 #include "fold-const.h"
132 #include "gimple-fold.h"
134 #include "gimplify.h"
135 #include "gimple-iterator.h"
136 #include "tree-cfg.h"
137 #include "tree-ssa-propagate.h"
139 #include "builtins.h"
141 #include "stor-layout.h"
142 #include "optabs-query.h"
143 #include "tree-ssa-ccp.h"
144 #include "tree-dfa.h"
145 #include "diagnostic-core.h"
146 #include "stringpool.h"
148 #include "tree-vector-builder.h"
150 #include "alloc-pool.h"
151 #include "symbol-summary.h"
152 #include "ipa-utils.h"
153 #include "ipa-prop.h"
155 /* Possible lattice values. */
164 class ccp_prop_value_t
{
167 ccp_lattice_t lattice_val
;
169 /* Propagated value. */
172 /* Mask that applies to the propagated value during CCP. For X
173 with a CONSTANT lattice value X & ~mask == value & ~mask. The
174 zero bits in the mask cover constant values. The ones mean no
179 class ccp_propagate
: public ssa_propagation_engine
182 enum ssa_prop_result
visit_stmt (gimple
*, edge
*, tree
*) FINAL OVERRIDE
;
183 enum ssa_prop_result
visit_phi (gphi
*) FINAL OVERRIDE
;
186 /* Array of propagated constant values. After propagation,
187 CONST_VAL[I].VALUE holds the constant value for SSA_NAME(I). If
188 the constant is held in an SSA name representing a memory store
189 (i.e., a VDEF), CONST_VAL[I].MEM_REF will contain the actual
190 memory reference used to store (i.e., the LHS of the assignment
192 static ccp_prop_value_t
*const_val
;
193 static unsigned n_const_val
;
195 static void canonicalize_value (ccp_prop_value_t
*);
196 static void ccp_lattice_meet (ccp_prop_value_t
*, ccp_prop_value_t
*);
198 /* Dump constant propagation value VAL to file OUTF prefixed by PREFIX. */
201 dump_lattice_value (FILE *outf
, const char *prefix
, ccp_prop_value_t val
)
203 switch (val
.lattice_val
)
206 fprintf (outf
, "%sUNINITIALIZED", prefix
);
209 fprintf (outf
, "%sUNDEFINED", prefix
);
212 fprintf (outf
, "%sVARYING", prefix
);
215 if (TREE_CODE (val
.value
) != INTEGER_CST
218 fprintf (outf
, "%sCONSTANT ", prefix
);
219 print_generic_expr (outf
, val
.value
, dump_flags
);
223 widest_int cval
= wi::bit_and_not (wi::to_widest (val
.value
),
225 fprintf (outf
, "%sCONSTANT ", prefix
);
226 print_hex (cval
, outf
);
227 fprintf (outf
, " (");
228 print_hex (val
.mask
, outf
);
238 /* Print lattice value VAL to stderr. */
240 void debug_lattice_value (ccp_prop_value_t val
);
243 debug_lattice_value (ccp_prop_value_t val
)
245 dump_lattice_value (stderr
, "", val
);
246 fprintf (stderr
, "\n");
249 /* Extend NONZERO_BITS to a full mask, based on sgn. */
252 extend_mask (const wide_int
&nonzero_bits
, signop sgn
)
254 return widest_int::from (nonzero_bits
, sgn
);
257 /* Compute a default value for variable VAR and store it in the
258 CONST_VAL array. The following rules are used to get default
261 1- Global and static variables that are declared constant are
264 2- Any other value is considered UNDEFINED. This is useful when
265 considering PHI nodes. PHI arguments that are undefined do not
266 change the constant value of the PHI node, which allows for more
267 constants to be propagated.
269 3- Variables defined by statements other than assignments and PHI
270 nodes are considered VARYING.
272 4- Initial values of variables that are not GIMPLE registers are
273 considered VARYING. */
275 static ccp_prop_value_t
276 get_default_value (tree var
)
278 ccp_prop_value_t val
= { UNINITIALIZED
, NULL_TREE
, 0 };
281 stmt
= SSA_NAME_DEF_STMT (var
);
283 if (gimple_nop_p (stmt
))
285 /* Variables defined by an empty statement are those used
286 before being initialized. If VAR is a local variable, we
287 can assume initially that it is UNDEFINED, otherwise we must
288 consider it VARYING. */
289 if (!virtual_operand_p (var
)
290 && SSA_NAME_VAR (var
)
291 && TREE_CODE (SSA_NAME_VAR (var
)) == VAR_DECL
)
292 val
.lattice_val
= UNDEFINED
;
295 val
.lattice_val
= VARYING
;
297 if (flag_tree_bit_ccp
)
299 wide_int nonzero_bits
= get_nonzero_bits (var
);
303 if (SSA_NAME_VAR (var
)
304 && TREE_CODE (SSA_NAME_VAR (var
)) == PARM_DECL
305 && ipcp_get_parm_bits (SSA_NAME_VAR (var
), &value
, &mask
))
307 val
.lattice_val
= CONSTANT
;
310 if (nonzero_bits
!= -1)
311 val
.mask
&= extend_mask (nonzero_bits
,
312 TYPE_SIGN (TREE_TYPE (var
)));
314 else if (nonzero_bits
!= -1)
316 val
.lattice_val
= CONSTANT
;
317 val
.value
= build_zero_cst (TREE_TYPE (var
));
318 val
.mask
= extend_mask (nonzero_bits
,
319 TYPE_SIGN (TREE_TYPE (var
)));
324 else if (is_gimple_assign (stmt
))
327 if (gimple_assign_single_p (stmt
)
328 && DECL_P (gimple_assign_rhs1 (stmt
))
329 && (cst
= get_symbol_constant_value (gimple_assign_rhs1 (stmt
))))
331 val
.lattice_val
= CONSTANT
;
336 /* Any other variable defined by an assignment is considered
338 val
.lattice_val
= UNDEFINED
;
341 else if ((is_gimple_call (stmt
)
342 && gimple_call_lhs (stmt
) != NULL_TREE
)
343 || gimple_code (stmt
) == GIMPLE_PHI
)
345 /* A variable defined by a call or a PHI node is considered
347 val
.lattice_val
= UNDEFINED
;
351 /* Otherwise, VAR will never take on a constant value. */
352 val
.lattice_val
= VARYING
;
360 /* Get the constant value associated with variable VAR. */
362 static inline ccp_prop_value_t
*
365 ccp_prop_value_t
*val
;
367 if (const_val
== NULL
368 || SSA_NAME_VERSION (var
) >= n_const_val
)
371 val
= &const_val
[SSA_NAME_VERSION (var
)];
372 if (val
->lattice_val
== UNINITIALIZED
)
373 *val
= get_default_value (var
);
375 canonicalize_value (val
);
380 /* Return the constant tree value associated with VAR. */
383 get_constant_value (tree var
)
385 ccp_prop_value_t
*val
;
386 if (TREE_CODE (var
) != SSA_NAME
)
388 if (is_gimple_min_invariant (var
))
392 val
= get_value (var
);
394 && val
->lattice_val
== CONSTANT
395 && (TREE_CODE (val
->value
) != INTEGER_CST
401 /* Sets the value associated with VAR to VARYING. */
404 set_value_varying (tree var
)
406 ccp_prop_value_t
*val
= &const_val
[SSA_NAME_VERSION (var
)];
408 val
->lattice_val
= VARYING
;
409 val
->value
= NULL_TREE
;
413 /* For integer constants, make sure to drop TREE_OVERFLOW. */
416 canonicalize_value (ccp_prop_value_t
*val
)
418 if (val
->lattice_val
!= CONSTANT
)
421 if (TREE_OVERFLOW_P (val
->value
))
422 val
->value
= drop_tree_overflow (val
->value
);
425 /* Return whether the lattice transition is valid. */
428 valid_lattice_transition (ccp_prop_value_t old_val
, ccp_prop_value_t new_val
)
430 /* Lattice transitions must always be monotonically increasing in
432 if (old_val
.lattice_val
< new_val
.lattice_val
)
435 if (old_val
.lattice_val
!= new_val
.lattice_val
)
438 if (!old_val
.value
&& !new_val
.value
)
441 /* Now both lattice values are CONSTANT. */
443 /* Allow arbitrary copy changes as we might look through PHI <a_1, ...>
444 when only a single copy edge is executable. */
445 if (TREE_CODE (old_val
.value
) == SSA_NAME
446 && TREE_CODE (new_val
.value
) == SSA_NAME
)
449 /* Allow transitioning from a constant to a copy. */
450 if (is_gimple_min_invariant (old_val
.value
)
451 && TREE_CODE (new_val
.value
) == SSA_NAME
)
454 /* Allow transitioning from PHI <&x, not executable> == &x
455 to PHI <&x, &y> == common alignment. */
456 if (TREE_CODE (old_val
.value
) != INTEGER_CST
457 && TREE_CODE (new_val
.value
) == INTEGER_CST
)
460 /* Bit-lattices have to agree in the still valid bits. */
461 if (TREE_CODE (old_val
.value
) == INTEGER_CST
462 && TREE_CODE (new_val
.value
) == INTEGER_CST
)
463 return (wi::bit_and_not (wi::to_widest (old_val
.value
), new_val
.mask
)
464 == wi::bit_and_not (wi::to_widest (new_val
.value
), new_val
.mask
));
466 /* Otherwise constant values have to agree. */
467 if (operand_equal_p (old_val
.value
, new_val
.value
, 0))
470 /* At least the kinds and types should agree now. */
471 if (TREE_CODE (old_val
.value
) != TREE_CODE (new_val
.value
)
472 || !types_compatible_p (TREE_TYPE (old_val
.value
),
473 TREE_TYPE (new_val
.value
)))
476 /* For floats and !HONOR_NANS allow transitions from (partial) NaN
478 tree type
= TREE_TYPE (new_val
.value
);
479 if (SCALAR_FLOAT_TYPE_P (type
)
480 && !HONOR_NANS (type
))
482 if (REAL_VALUE_ISNAN (TREE_REAL_CST (old_val
.value
)))
485 else if (VECTOR_FLOAT_TYPE_P (type
)
486 && !HONOR_NANS (type
))
489 = tree_vector_builder::binary_encoded_nelts (old_val
.value
,
491 for (unsigned int i
= 0; i
< count
; ++i
)
492 if (!REAL_VALUE_ISNAN
493 (TREE_REAL_CST (VECTOR_CST_ENCODED_ELT (old_val
.value
, i
)))
494 && !operand_equal_p (VECTOR_CST_ENCODED_ELT (old_val
.value
, i
),
495 VECTOR_CST_ENCODED_ELT (new_val
.value
, i
), 0))
499 else if (COMPLEX_FLOAT_TYPE_P (type
)
500 && !HONOR_NANS (type
))
502 if (!REAL_VALUE_ISNAN (TREE_REAL_CST (TREE_REALPART (old_val
.value
)))
503 && !operand_equal_p (TREE_REALPART (old_val
.value
),
504 TREE_REALPART (new_val
.value
), 0))
506 if (!REAL_VALUE_ISNAN (TREE_REAL_CST (TREE_IMAGPART (old_val
.value
)))
507 && !operand_equal_p (TREE_IMAGPART (old_val
.value
),
508 TREE_IMAGPART (new_val
.value
), 0))
515 /* Set the value for variable VAR to NEW_VAL. Return true if the new
516 value is different from VAR's previous value. */
519 set_lattice_value (tree var
, ccp_prop_value_t
*new_val
)
521 /* We can deal with old UNINITIALIZED values just fine here. */
522 ccp_prop_value_t
*old_val
= &const_val
[SSA_NAME_VERSION (var
)];
524 canonicalize_value (new_val
);
526 /* We have to be careful to not go up the bitwise lattice
527 represented by the mask. Instead of dropping to VARYING
528 use the meet operator to retain a conservative value.
529 Missed optimizations like PR65851 makes this necessary.
530 It also ensures we converge to a stable lattice solution. */
531 if (old_val
->lattice_val
!= UNINITIALIZED
)
532 ccp_lattice_meet (new_val
, old_val
);
534 gcc_checking_assert (valid_lattice_transition (*old_val
, *new_val
));
536 /* If *OLD_VAL and NEW_VAL are the same, return false to inform the
537 caller that this was a non-transition. */
538 if (old_val
->lattice_val
!= new_val
->lattice_val
539 || (new_val
->lattice_val
== CONSTANT
540 && (TREE_CODE (new_val
->value
) != TREE_CODE (old_val
->value
)
541 || (TREE_CODE (new_val
->value
) == INTEGER_CST
542 && (new_val
->mask
!= old_val
->mask
543 || (wi::bit_and_not (wi::to_widest (old_val
->value
),
545 != wi::bit_and_not (wi::to_widest (new_val
->value
),
547 || (TREE_CODE (new_val
->value
) != INTEGER_CST
548 && !operand_equal_p (new_val
->value
, old_val
->value
, 0)))))
550 /* ??? We would like to delay creation of INTEGER_CSTs from
551 partially constants here. */
553 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
555 dump_lattice_value (dump_file
, "Lattice value changed to ", *new_val
);
556 fprintf (dump_file
, ". Adding SSA edges to worklist.\n");
561 gcc_assert (new_val
->lattice_val
!= UNINITIALIZED
);
568 static ccp_prop_value_t
get_value_for_expr (tree
, bool);
569 static ccp_prop_value_t
bit_value_binop (enum tree_code
, tree
, tree
, tree
);
570 void bit_value_binop (enum tree_code
, signop
, int, widest_int
*, widest_int
*,
571 signop
, int, const widest_int
&, const widest_int
&,
572 signop
, int, const widest_int
&, const widest_int
&);
574 /* Return a widest_int that can be used for bitwise simplifications
578 value_to_wide_int (ccp_prop_value_t val
)
581 && TREE_CODE (val
.value
) == INTEGER_CST
)
582 return wi::to_widest (val
.value
);
587 /* Return the value for the address expression EXPR based on alignment
590 static ccp_prop_value_t
591 get_value_from_alignment (tree expr
)
593 tree type
= TREE_TYPE (expr
);
594 ccp_prop_value_t val
;
595 unsigned HOST_WIDE_INT bitpos
;
598 gcc_assert (TREE_CODE (expr
) == ADDR_EXPR
);
600 get_pointer_alignment_1 (expr
, &align
, &bitpos
);
601 val
.mask
= wi::bit_and_not
602 (POINTER_TYPE_P (type
) || TYPE_UNSIGNED (type
)
603 ? wi::mask
<widest_int
> (TYPE_PRECISION (type
), false)
605 align
/ BITS_PER_UNIT
- 1);
607 = wi::sext (val
.mask
, TYPE_PRECISION (type
)) == -1 ? VARYING
: CONSTANT
;
608 if (val
.lattice_val
== CONSTANT
)
609 val
.value
= build_int_cstu (type
, bitpos
/ BITS_PER_UNIT
);
611 val
.value
= NULL_TREE
;
616 /* Return the value for the tree operand EXPR. If FOR_BITS_P is true
617 return constant bits extracted from alignment information for
618 invariant addresses. */
620 static ccp_prop_value_t
621 get_value_for_expr (tree expr
, bool for_bits_p
)
623 ccp_prop_value_t val
;
625 if (TREE_CODE (expr
) == SSA_NAME
)
627 ccp_prop_value_t
*val_
= get_value (expr
);
632 val
.lattice_val
= VARYING
;
633 val
.value
= NULL_TREE
;
637 && val
.lattice_val
== CONSTANT
)
639 if (TREE_CODE (val
.value
) == ADDR_EXPR
)
640 val
= get_value_from_alignment (val
.value
);
641 else if (TREE_CODE (val
.value
) != INTEGER_CST
)
643 val
.lattice_val
= VARYING
;
644 val
.value
= NULL_TREE
;
648 /* Fall back to a copy value. */
650 && val
.lattice_val
== VARYING
651 && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (expr
))
653 val
.lattice_val
= CONSTANT
;
658 else if (is_gimple_min_invariant (expr
)
659 && (!for_bits_p
|| TREE_CODE (expr
) == INTEGER_CST
))
661 val
.lattice_val
= CONSTANT
;
664 canonicalize_value (&val
);
666 else if (TREE_CODE (expr
) == ADDR_EXPR
)
667 val
= get_value_from_alignment (expr
);
670 val
.lattice_val
= VARYING
;
672 val
.value
= NULL_TREE
;
675 if (val
.lattice_val
== VARYING
676 && TYPE_UNSIGNED (TREE_TYPE (expr
)))
677 val
.mask
= wi::zext (val
.mask
, TYPE_PRECISION (TREE_TYPE (expr
)));
682 /* Return the likely CCP lattice value for STMT.
684 If STMT has no operands, then return CONSTANT.
686 Else if undefinedness of operands of STMT cause its value to be
687 undefined, then return UNDEFINED.
689 Else if any operands of STMT are constants, then return CONSTANT.
691 Else return VARYING. */
694 likely_value (gimple
*stmt
)
696 bool has_constant_operand
, has_undefined_operand
, all_undefined_operands
;
697 bool has_nsa_operand
;
702 enum gimple_code code
= gimple_code (stmt
);
704 /* This function appears to be called only for assignments, calls,
705 conditionals, and switches, due to the logic in visit_stmt. */
706 gcc_assert (code
== GIMPLE_ASSIGN
707 || code
== GIMPLE_CALL
708 || code
== GIMPLE_COND
709 || code
== GIMPLE_SWITCH
);
711 /* If the statement has volatile operands, it won't fold to a
713 if (gimple_has_volatile_ops (stmt
))
716 /* Arrive here for more complex cases. */
717 has_constant_operand
= false;
718 has_undefined_operand
= false;
719 all_undefined_operands
= true;
720 has_nsa_operand
= false;
721 FOR_EACH_SSA_TREE_OPERAND (use
, stmt
, iter
, SSA_OP_USE
)
723 ccp_prop_value_t
*val
= get_value (use
);
725 if (val
&& val
->lattice_val
== UNDEFINED
)
726 has_undefined_operand
= true;
728 all_undefined_operands
= false;
730 if (val
&& val
->lattice_val
== CONSTANT
)
731 has_constant_operand
= true;
733 if (SSA_NAME_IS_DEFAULT_DEF (use
)
734 || !prop_simulate_again_p (SSA_NAME_DEF_STMT (use
)))
735 has_nsa_operand
= true;
738 /* There may be constants in regular rhs operands. For calls we
739 have to ignore lhs, fndecl and static chain, otherwise only
741 for (i
= (is_gimple_call (stmt
) ? 2 : 0) + gimple_has_lhs (stmt
);
742 i
< gimple_num_ops (stmt
); ++i
)
744 tree op
= gimple_op (stmt
, i
);
745 if (!op
|| TREE_CODE (op
) == SSA_NAME
)
747 if (is_gimple_min_invariant (op
))
748 has_constant_operand
= true;
751 if (has_constant_operand
)
752 all_undefined_operands
= false;
754 if (has_undefined_operand
755 && code
== GIMPLE_CALL
756 && gimple_call_internal_p (stmt
))
757 switch (gimple_call_internal_fn (stmt
))
759 /* These 3 builtins use the first argument just as a magic
760 way how to find out a decl uid. */
761 case IFN_GOMP_SIMD_LANE
:
762 case IFN_GOMP_SIMD_VF
:
763 case IFN_GOMP_SIMD_LAST_LANE
:
764 has_undefined_operand
= false;
770 /* If the operation combines operands like COMPLEX_EXPR make sure to
771 not mark the result UNDEFINED if only one part of the result is
773 if (has_undefined_operand
&& all_undefined_operands
)
775 else if (code
== GIMPLE_ASSIGN
&& has_undefined_operand
)
777 switch (gimple_assign_rhs_code (stmt
))
779 /* Unary operators are handled with all_undefined_operands. */
782 case POINTER_PLUS_EXPR
:
784 /* Not MIN_EXPR, MAX_EXPR. One VARYING operand may be selected.
785 Not bitwise operators, one VARYING operand may specify the
787 Not logical operators for the same reason, apart from XOR.
788 Not COMPLEX_EXPR as one VARYING operand makes the result partly
789 not UNDEFINED. Not *DIV_EXPR, comparisons and shifts because
790 the undefined operand may be promoted. */
794 /* If any part of an address is UNDEFINED, like the index
795 of an ARRAY_EXPR, then treat the result as UNDEFINED. */
802 /* If there was an UNDEFINED operand but the result may be not UNDEFINED
803 fall back to CONSTANT. During iteration UNDEFINED may still drop
805 if (has_undefined_operand
)
808 /* We do not consider virtual operands here -- load from read-only
809 memory may have only VARYING virtual operands, but still be
810 constant. Also we can combine the stmt with definitions from
811 operands whose definitions are not simulated again. */
812 if (has_constant_operand
814 || gimple_references_memory_p (stmt
))
820 /* Returns true if STMT cannot be constant. */
823 surely_varying_stmt_p (gimple
*stmt
)
825 /* If the statement has operands that we cannot handle, it cannot be
827 if (gimple_has_volatile_ops (stmt
))
830 /* If it is a call and does not return a value or is not a
831 builtin and not an indirect call or a call to function with
832 assume_aligned/alloc_align attribute, it is varying. */
833 if (is_gimple_call (stmt
))
835 tree fndecl
, fntype
= gimple_call_fntype (stmt
);
836 if (!gimple_call_lhs (stmt
)
837 || ((fndecl
= gimple_call_fndecl (stmt
)) != NULL_TREE
838 && !fndecl_built_in_p (fndecl
)
839 && !lookup_attribute ("assume_aligned",
840 TYPE_ATTRIBUTES (fntype
))
841 && !lookup_attribute ("alloc_align",
842 TYPE_ATTRIBUTES (fntype
))))
846 /* Any other store operation is not interesting. */
847 else if (gimple_vdef (stmt
))
850 /* Anything other than assignments and conditional jumps are not
851 interesting for CCP. */
852 if (gimple_code (stmt
) != GIMPLE_ASSIGN
853 && gimple_code (stmt
) != GIMPLE_COND
854 && gimple_code (stmt
) != GIMPLE_SWITCH
855 && gimple_code (stmt
) != GIMPLE_CALL
)
861 /* Initialize local data structures for CCP. */
864 ccp_initialize (void)
868 n_const_val
= num_ssa_names
;
869 const_val
= XCNEWVEC (ccp_prop_value_t
, n_const_val
);
871 /* Initialize simulation flags for PHI nodes and statements. */
872 FOR_EACH_BB_FN (bb
, cfun
)
874 gimple_stmt_iterator i
;
876 for (i
= gsi_start_bb (bb
); !gsi_end_p (i
); gsi_next (&i
))
878 gimple
*stmt
= gsi_stmt (i
);
881 /* If the statement is a control insn, then we do not
882 want to avoid simulating the statement once. Failure
883 to do so means that those edges will never get added. */
884 if (stmt_ends_bb_p (stmt
))
887 is_varying
= surely_varying_stmt_p (stmt
);
894 /* If the statement will not produce a constant, mark
895 all its outputs VARYING. */
896 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, iter
, SSA_OP_ALL_DEFS
)
897 set_value_varying (def
);
899 prop_set_simulate_again (stmt
, !is_varying
);
903 /* Now process PHI nodes. We never clear the simulate_again flag on
904 phi nodes, since we do not know which edges are executable yet,
905 except for phi nodes for virtual operands when we do not do store ccp. */
906 FOR_EACH_BB_FN (bb
, cfun
)
910 for (i
= gsi_start_phis (bb
); !gsi_end_p (i
); gsi_next (&i
))
912 gphi
*phi
= i
.phi ();
914 if (virtual_operand_p (gimple_phi_result (phi
)))
915 prop_set_simulate_again (phi
, false);
917 prop_set_simulate_again (phi
, true);
922 /* Debug count support. Reset the values of ssa names
923 VARYING when the total number ssa names analyzed is
924 beyond the debug count specified. */
930 for (i
= 0; i
< num_ssa_names
; i
++)
934 const_val
[i
].lattice_val
= VARYING
;
935 const_val
[i
].mask
= -1;
936 const_val
[i
].value
= NULL_TREE
;
942 /* We want to provide our own GET_VALUE and FOLD_STMT virtual methods. */
943 class ccp_folder
: public substitute_and_fold_engine
946 tree
get_value (tree
) FINAL OVERRIDE
;
947 bool fold_stmt (gimple_stmt_iterator
*) FINAL OVERRIDE
;
950 /* This method just wraps GET_CONSTANT_VALUE for now. Over time
951 naked calls to GET_CONSTANT_VALUE should be eliminated in favor
952 of calling member functions. */
955 ccp_folder::get_value (tree op
)
957 return get_constant_value (op
);
960 /* Do final substitution of propagated values, cleanup the flowgraph and
961 free allocated storage. If NONZERO_P, record nonzero bits.
963 Return TRUE when something was optimized. */
966 ccp_finalize (bool nonzero_p
)
968 bool something_changed
;
974 /* Derive alignment and misalignment information from partially
975 constant pointers in the lattice or nonzero bits from partially
976 constant integers. */
977 FOR_EACH_SSA_NAME (i
, name
, cfun
)
979 ccp_prop_value_t
*val
;
980 unsigned int tem
, align
;
982 if (!POINTER_TYPE_P (TREE_TYPE (name
))
983 && (!INTEGRAL_TYPE_P (TREE_TYPE (name
))
984 /* Don't record nonzero bits before IPA to avoid
985 using too much memory. */
989 val
= get_value (name
);
990 if (val
->lattice_val
!= CONSTANT
991 || TREE_CODE (val
->value
) != INTEGER_CST
995 if (POINTER_TYPE_P (TREE_TYPE (name
)))
997 /* Trailing mask bits specify the alignment, trailing value
998 bits the misalignment. */
999 tem
= val
->mask
.to_uhwi ();
1000 align
= least_bit_hwi (tem
);
1002 set_ptr_info_alignment (get_ptr_info (name
), align
,
1003 (TREE_INT_CST_LOW (val
->value
)
1008 unsigned int precision
= TYPE_PRECISION (TREE_TYPE (val
->value
));
1009 wide_int nonzero_bits
1010 = (wide_int::from (val
->mask
, precision
, UNSIGNED
)
1011 | wi::to_wide (val
->value
));
1012 nonzero_bits
&= get_nonzero_bits (name
);
1013 set_nonzero_bits (name
, nonzero_bits
);
1017 /* Perform substitutions based on the known constant values. */
1018 class ccp_folder ccp_folder
;
1019 something_changed
= ccp_folder
.substitute_and_fold ();
1023 return something_changed
;
1027 /* Compute the meet operator between *VAL1 and *VAL2. Store the result
1030 any M UNDEFINED = any
1031 any M VARYING = VARYING
1032 Ci M Cj = Ci if (i == j)
1033 Ci M Cj = VARYING if (i != j)
1037 ccp_lattice_meet (ccp_prop_value_t
*val1
, ccp_prop_value_t
*val2
)
1039 if (val1
->lattice_val
== UNDEFINED
1040 /* For UNDEFINED M SSA we can't always SSA because its definition
1041 may not dominate the PHI node. Doing optimistic copy propagation
1042 also causes a lot of gcc.dg/uninit-pred*.c FAILs. */
1043 && (val2
->lattice_val
!= CONSTANT
1044 || TREE_CODE (val2
->value
) != SSA_NAME
))
1046 /* UNDEFINED M any = any */
1049 else if (val2
->lattice_val
== UNDEFINED
1051 && (val1
->lattice_val
!= CONSTANT
1052 || TREE_CODE (val1
->value
) != SSA_NAME
))
1054 /* any M UNDEFINED = any
1055 Nothing to do. VAL1 already contains the value we want. */
1058 else if (val1
->lattice_val
== VARYING
1059 || val2
->lattice_val
== VARYING
)
1061 /* any M VARYING = VARYING. */
1062 val1
->lattice_val
= VARYING
;
1064 val1
->value
= NULL_TREE
;
1066 else if (val1
->lattice_val
== CONSTANT
1067 && val2
->lattice_val
== CONSTANT
1068 && TREE_CODE (val1
->value
) == INTEGER_CST
1069 && TREE_CODE (val2
->value
) == INTEGER_CST
)
1071 /* Ci M Cj = Ci if (i == j)
1072 Ci M Cj = VARYING if (i != j)
1074 For INTEGER_CSTs mask unequal bits. If no equal bits remain,
1076 val1
->mask
= (val1
->mask
| val2
->mask
1077 | (wi::to_widest (val1
->value
)
1078 ^ wi::to_widest (val2
->value
)));
1079 if (wi::sext (val1
->mask
, TYPE_PRECISION (TREE_TYPE (val1
->value
))) == -1)
1081 val1
->lattice_val
= VARYING
;
1082 val1
->value
= NULL_TREE
;
1085 else if (val1
->lattice_val
== CONSTANT
1086 && val2
->lattice_val
== CONSTANT
1087 && operand_equal_p (val1
->value
, val2
->value
, 0))
1089 /* Ci M Cj = Ci if (i == j)
1090 Ci M Cj = VARYING if (i != j)
1092 VAL1 already contains the value we want for equivalent values. */
1094 else if (val1
->lattice_val
== CONSTANT
1095 && val2
->lattice_val
== CONSTANT
1096 && (TREE_CODE (val1
->value
) == ADDR_EXPR
1097 || TREE_CODE (val2
->value
) == ADDR_EXPR
))
1099 /* When not equal addresses are involved try meeting for
1101 ccp_prop_value_t tem
= *val2
;
1102 if (TREE_CODE (val1
->value
) == ADDR_EXPR
)
1103 *val1
= get_value_for_expr (val1
->value
, true);
1104 if (TREE_CODE (val2
->value
) == ADDR_EXPR
)
1105 tem
= get_value_for_expr (val2
->value
, true);
1106 ccp_lattice_meet (val1
, &tem
);
1110 /* Any other combination is VARYING. */
1111 val1
->lattice_val
= VARYING
;
1113 val1
->value
= NULL_TREE
;
1118 /* Loop through the PHI_NODE's parameters for BLOCK and compare their
1119 lattice values to determine PHI_NODE's lattice value. The value of a
1120 PHI node is determined calling ccp_lattice_meet with all the arguments
1121 of the PHI node that are incoming via executable edges. */
1123 enum ssa_prop_result
1124 ccp_propagate::visit_phi (gphi
*phi
)
1127 ccp_prop_value_t new_val
;
1129 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1131 fprintf (dump_file
, "\nVisiting PHI node: ");
1132 print_gimple_stmt (dump_file
, phi
, 0, dump_flags
);
1135 new_val
.lattice_val
= UNDEFINED
;
1136 new_val
.value
= NULL_TREE
;
1140 bool non_exec_edge
= false;
1141 for (i
= 0; i
< gimple_phi_num_args (phi
); i
++)
1143 /* Compute the meet operator over all the PHI arguments flowing
1144 through executable edges. */
1145 edge e
= gimple_phi_arg_edge (phi
, i
);
1147 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1150 "\tArgument #%d (%d -> %d %sexecutable)\n",
1151 i
, e
->src
->index
, e
->dest
->index
,
1152 (e
->flags
& EDGE_EXECUTABLE
) ? "" : "not ");
1155 /* If the incoming edge is executable, Compute the meet operator for
1156 the existing value of the PHI node and the current PHI argument. */
1157 if (e
->flags
& EDGE_EXECUTABLE
)
1159 tree arg
= gimple_phi_arg (phi
, i
)->def
;
1160 ccp_prop_value_t arg_val
= get_value_for_expr (arg
, false);
1168 ccp_lattice_meet (&new_val
, &arg_val
);
1170 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1172 fprintf (dump_file
, "\t");
1173 print_generic_expr (dump_file
, arg
, dump_flags
);
1174 dump_lattice_value (dump_file
, "\tValue: ", arg_val
);
1175 fprintf (dump_file
, "\n");
1178 if (new_val
.lattice_val
== VARYING
)
1182 non_exec_edge
= true;
1185 /* In case there were non-executable edges and the value is a copy
1186 make sure its definition dominates the PHI node. */
1188 && new_val
.lattice_val
== CONSTANT
1189 && TREE_CODE (new_val
.value
) == SSA_NAME
1190 && ! SSA_NAME_IS_DEFAULT_DEF (new_val
.value
)
1191 && ! dominated_by_p (CDI_DOMINATORS
, gimple_bb (phi
),
1192 gimple_bb (SSA_NAME_DEF_STMT (new_val
.value
))))
1194 new_val
.lattice_val
= VARYING
;
1195 new_val
.value
= NULL_TREE
;
1199 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1201 dump_lattice_value (dump_file
, "\n PHI node value: ", new_val
);
1202 fprintf (dump_file
, "\n\n");
1205 /* Make the transition to the new value. */
1206 if (set_lattice_value (gimple_phi_result (phi
), &new_val
))
1208 if (new_val
.lattice_val
== VARYING
)
1209 return SSA_PROP_VARYING
;
1211 return SSA_PROP_INTERESTING
;
1214 return SSA_PROP_NOT_INTERESTING
;
1217 /* Return the constant value for OP or OP otherwise. */
1220 valueize_op (tree op
)
1222 if (TREE_CODE (op
) == SSA_NAME
)
1224 tree tem
= get_constant_value (op
);
1231 /* Return the constant value for OP, but signal to not follow SSA
1232 edges if the definition may be simulated again. */
1235 valueize_op_1 (tree op
)
1237 if (TREE_CODE (op
) == SSA_NAME
)
1239 /* If the definition may be simulated again we cannot follow
1240 this SSA edge as the SSA propagator does not necessarily
1241 re-visit the use. */
1242 gimple
*def_stmt
= SSA_NAME_DEF_STMT (op
);
1243 if (!gimple_nop_p (def_stmt
)
1244 && prop_simulate_again_p (def_stmt
))
1246 tree tem
= get_constant_value (op
);
1253 /* CCP specific front-end to the non-destructive constant folding
1256 Attempt to simplify the RHS of STMT knowing that one or more
1257 operands are constants.
1259 If simplification is possible, return the simplified RHS,
1260 otherwise return the original RHS or NULL_TREE. */
1263 ccp_fold (gimple
*stmt
)
1265 location_t loc
= gimple_location (stmt
);
1266 switch (gimple_code (stmt
))
1270 /* Handle comparison operators that can appear in GIMPLE form. */
1271 tree op0
= valueize_op (gimple_cond_lhs (stmt
));
1272 tree op1
= valueize_op (gimple_cond_rhs (stmt
));
1273 enum tree_code code
= gimple_cond_code (stmt
);
1274 return fold_binary_loc (loc
, code
, boolean_type_node
, op0
, op1
);
1279 /* Return the constant switch index. */
1280 return valueize_op (gimple_switch_index (as_a
<gswitch
*> (stmt
)));
1285 return gimple_fold_stmt_to_constant_1 (stmt
,
1286 valueize_op
, valueize_op_1
);
1293 /* Apply the operation CODE in type TYPE to the value, mask pair
1294 RVAL and RMASK representing a value of type RTYPE and set
1295 the value, mask pair *VAL and *MASK to the result. */
1298 bit_value_unop (enum tree_code code
, signop type_sgn
, int type_precision
,
1299 widest_int
*val
, widest_int
*mask
,
1300 signop rtype_sgn
, int rtype_precision
,
1301 const widest_int
&rval
, const widest_int
&rmask
)
1312 widest_int temv
, temm
;
1313 /* Return ~rval + 1. */
1314 bit_value_unop (BIT_NOT_EXPR
, type_sgn
, type_precision
, &temv
, &temm
,
1315 type_sgn
, type_precision
, rval
, rmask
);
1316 bit_value_binop (PLUS_EXPR
, type_sgn
, type_precision
, val
, mask
,
1317 type_sgn
, type_precision
, temv
, temm
,
1318 type_sgn
, type_precision
, 1, 0);
1324 /* First extend mask and value according to the original type. */
1325 *mask
= wi::ext (rmask
, rtype_precision
, rtype_sgn
);
1326 *val
= wi::ext (rval
, rtype_precision
, rtype_sgn
);
1328 /* Then extend mask and value according to the target type. */
1329 *mask
= wi::ext (*mask
, type_precision
, type_sgn
);
1330 *val
= wi::ext (*val
, type_precision
, type_sgn
);
1340 /* Apply the operation CODE in type TYPE to the value, mask pairs
1341 R1VAL, R1MASK and R2VAL, R2MASK representing a values of type R1TYPE
1342 and R2TYPE and set the value, mask pair *VAL and *MASK to the result. */
1345 bit_value_binop (enum tree_code code
, signop sgn
, int width
,
1346 widest_int
*val
, widest_int
*mask
,
1347 signop r1type_sgn
, int r1type_precision
,
1348 const widest_int
&r1val
, const widest_int
&r1mask
,
1349 signop r2type_sgn
, int r2type_precision
,
1350 const widest_int
&r2val
, const widest_int
&r2mask
)
1352 bool swap_p
= false;
1354 /* Assume we'll get a constant result. Use an initial non varying
1355 value, we fall back to varying in the end if necessary. */
1361 /* The mask is constant where there is a known not
1362 set bit, (m1 | m2) & ((v1 | m1) & (v2 | m2)) */
1363 *mask
= (r1mask
| r2mask
) & (r1val
| r1mask
) & (r2val
| r2mask
);
1364 *val
= r1val
& r2val
;
1368 /* The mask is constant where there is a known
1369 set bit, (m1 | m2) & ~((v1 & ~m1) | (v2 & ~m2)). */
1370 *mask
= wi::bit_and_not (r1mask
| r2mask
,
1371 wi::bit_and_not (r1val
, r1mask
)
1372 | wi::bit_and_not (r2val
, r2mask
));
1373 *val
= r1val
| r2val
;
1378 *mask
= r1mask
| r2mask
;
1379 *val
= r1val
^ r2val
;
1386 widest_int shift
= r2val
;
1394 if (wi::neg_p (shift
))
1397 if (code
== RROTATE_EXPR
)
1398 code
= LROTATE_EXPR
;
1400 code
= RROTATE_EXPR
;
1402 if (code
== RROTATE_EXPR
)
1404 *mask
= wi::rrotate (r1mask
, shift
, width
);
1405 *val
= wi::rrotate (r1val
, shift
, width
);
1409 *mask
= wi::lrotate (r1mask
, shift
, width
);
1410 *val
= wi::lrotate (r1val
, shift
, width
);
1418 /* ??? We can handle partially known shift counts if we know
1419 its sign. That way we can tell that (x << (y | 8)) & 255
1423 widest_int shift
= r2val
;
1431 if (wi::neg_p (shift
))
1434 if (code
== RSHIFT_EXPR
)
1439 if (code
== RSHIFT_EXPR
)
1441 *mask
= wi::rshift (wi::ext (r1mask
, width
, sgn
), shift
, sgn
);
1442 *val
= wi::rshift (wi::ext (r1val
, width
, sgn
), shift
, sgn
);
1446 *mask
= wi::ext (r1mask
<< shift
, width
, sgn
);
1447 *val
= wi::ext (r1val
<< shift
, width
, sgn
);
1454 case POINTER_PLUS_EXPR
:
1456 /* Do the addition with unknown bits set to zero, to give carry-ins of
1457 zero wherever possible. */
1458 widest_int lo
= (wi::bit_and_not (r1val
, r1mask
)
1459 + wi::bit_and_not (r2val
, r2mask
));
1460 lo
= wi::ext (lo
, width
, sgn
);
1461 /* Do the addition with unknown bits set to one, to give carry-ins of
1462 one wherever possible. */
1463 widest_int hi
= (r1val
| r1mask
) + (r2val
| r2mask
);
1464 hi
= wi::ext (hi
, width
, sgn
);
1465 /* Each bit in the result is known if (a) the corresponding bits in
1466 both inputs are known, and (b) the carry-in to that bit position
1467 is known. We can check condition (b) by seeing if we got the same
1468 result with minimised carries as with maximised carries. */
1469 *mask
= r1mask
| r2mask
| (lo
^ hi
);
1470 *mask
= wi::ext (*mask
, width
, sgn
);
1471 /* It shouldn't matter whether we choose lo or hi here. */
1478 widest_int temv
, temm
;
1479 bit_value_unop (NEGATE_EXPR
, r2type_sgn
, r2type_precision
, &temv
, &temm
,
1480 r2type_sgn
, r2type_precision
, r2val
, r2mask
);
1481 bit_value_binop (PLUS_EXPR
, sgn
, width
, val
, mask
,
1482 r1type_sgn
, r1type_precision
, r1val
, r1mask
,
1483 r2type_sgn
, r2type_precision
, temv
, temm
);
1489 /* Just track trailing zeros in both operands and transfer
1490 them to the other. */
1491 int r1tz
= wi::ctz (r1val
| r1mask
);
1492 int r2tz
= wi::ctz (r2val
| r2mask
);
1493 if (r1tz
+ r2tz
>= width
)
1498 else if (r1tz
+ r2tz
> 0)
1500 *mask
= wi::ext (wi::mask
<widest_int
> (r1tz
+ r2tz
, true),
1510 widest_int m
= r1mask
| r2mask
;
1511 if (wi::bit_and_not (r1val
, m
) != wi::bit_and_not (r2val
, m
))
1514 *val
= ((code
== EQ_EXPR
) ? 0 : 1);
1518 /* We know the result of a comparison is always one or zero. */
1528 code
= swap_tree_comparison (code
);
1535 const widest_int
&o1val
= swap_p
? r2val
: r1val
;
1536 const widest_int
&o1mask
= swap_p
? r2mask
: r1mask
;
1537 const widest_int
&o2val
= swap_p
? r1val
: r2val
;
1538 const widest_int
&o2mask
= swap_p
? r1mask
: r2mask
;
1540 /* If the most significant bits are not known we know nothing. */
1541 if (wi::neg_p (o1mask
) || wi::neg_p (o2mask
))
1544 /* For comparisons the signedness is in the comparison operands. */
1547 /* If we know the most significant bits we know the values
1548 value ranges by means of treating varying bits as zero
1549 or one. Do a cross comparison of the max/min pairs. */
1550 maxmin
= wi::cmp (o1val
| o1mask
,
1551 wi::bit_and_not (o2val
, o2mask
), sgn
);
1552 minmax
= wi::cmp (wi::bit_and_not (o1val
, o1mask
),
1553 o2val
| o2mask
, sgn
);
1554 if (maxmin
< 0) /* o1 is less than o2. */
1559 else if (minmax
> 0) /* o1 is not less or equal to o2. */
1564 else if (maxmin
== minmax
) /* o1 and o2 are equal. */
1566 /* This probably should never happen as we'd have
1567 folded the thing during fully constant value folding. */
1569 *val
= (code
== LE_EXPR
? 1 : 0);
1573 /* We know the result of a comparison is always one or zero. */
1584 /* Return the propagation value when applying the operation CODE to
1585 the value RHS yielding type TYPE. */
1587 static ccp_prop_value_t
1588 bit_value_unop (enum tree_code code
, tree type
, tree rhs
)
1590 ccp_prop_value_t rval
= get_value_for_expr (rhs
, true);
1591 widest_int value
, mask
;
1592 ccp_prop_value_t val
;
1594 if (rval
.lattice_val
== UNDEFINED
)
1597 gcc_assert ((rval
.lattice_val
== CONSTANT
1598 && TREE_CODE (rval
.value
) == INTEGER_CST
)
1599 || wi::sext (rval
.mask
, TYPE_PRECISION (TREE_TYPE (rhs
))) == -1);
1600 bit_value_unop (code
, TYPE_SIGN (type
), TYPE_PRECISION (type
), &value
, &mask
,
1601 TYPE_SIGN (TREE_TYPE (rhs
)), TYPE_PRECISION (TREE_TYPE (rhs
)),
1602 value_to_wide_int (rval
), rval
.mask
);
1603 if (wi::sext (mask
, TYPE_PRECISION (type
)) != -1)
1605 val
.lattice_val
= CONSTANT
;
1607 /* ??? Delay building trees here. */
1608 val
.value
= wide_int_to_tree (type
, value
);
1612 val
.lattice_val
= VARYING
;
1613 val
.value
= NULL_TREE
;
1619 /* Return the propagation value when applying the operation CODE to
1620 the values RHS1 and RHS2 yielding type TYPE. */
1622 static ccp_prop_value_t
1623 bit_value_binop (enum tree_code code
, tree type
, tree rhs1
, tree rhs2
)
1625 ccp_prop_value_t r1val
= get_value_for_expr (rhs1
, true);
1626 ccp_prop_value_t r2val
= get_value_for_expr (rhs2
, true);
1627 widest_int value
, mask
;
1628 ccp_prop_value_t val
;
1630 if (r1val
.lattice_val
== UNDEFINED
1631 || r2val
.lattice_val
== UNDEFINED
)
1633 val
.lattice_val
= VARYING
;
1634 val
.value
= NULL_TREE
;
1639 gcc_assert ((r1val
.lattice_val
== CONSTANT
1640 && TREE_CODE (r1val
.value
) == INTEGER_CST
)
1641 || wi::sext (r1val
.mask
,
1642 TYPE_PRECISION (TREE_TYPE (rhs1
))) == -1);
1643 gcc_assert ((r2val
.lattice_val
== CONSTANT
1644 && TREE_CODE (r2val
.value
) == INTEGER_CST
)
1645 || wi::sext (r2val
.mask
,
1646 TYPE_PRECISION (TREE_TYPE (rhs2
))) == -1);
1647 bit_value_binop (code
, TYPE_SIGN (type
), TYPE_PRECISION (type
), &value
, &mask
,
1648 TYPE_SIGN (TREE_TYPE (rhs1
)), TYPE_PRECISION (TREE_TYPE (rhs1
)),
1649 value_to_wide_int (r1val
), r1val
.mask
,
1650 TYPE_SIGN (TREE_TYPE (rhs2
)), TYPE_PRECISION (TREE_TYPE (rhs2
)),
1651 value_to_wide_int (r2val
), r2val
.mask
);
1653 if (wi::sext (mask
, TYPE_PRECISION (type
)) != -1)
1655 val
.lattice_val
= CONSTANT
;
1657 /* ??? Delay building trees here. */
1658 val
.value
= wide_int_to_tree (type
, value
);
1662 val
.lattice_val
= VARYING
;
1663 val
.value
= NULL_TREE
;
1669 /* Return the propagation value for __builtin_assume_aligned
1670 and functions with assume_aligned or alloc_aligned attribute.
1671 For __builtin_assume_aligned, ATTR is NULL_TREE,
1672 for assume_aligned attribute ATTR is non-NULL and ALLOC_ALIGNED
1673 is false, for alloc_aligned attribute ATTR is non-NULL and
1674 ALLOC_ALIGNED is true. */
1676 static ccp_prop_value_t
1677 bit_value_assume_aligned (gimple
*stmt
, tree attr
, ccp_prop_value_t ptrval
,
1680 tree align
, misalign
= NULL_TREE
, type
;
1681 unsigned HOST_WIDE_INT aligni
, misaligni
= 0;
1682 ccp_prop_value_t alignval
;
1683 widest_int value
, mask
;
1684 ccp_prop_value_t val
;
1686 if (attr
== NULL_TREE
)
1688 tree ptr
= gimple_call_arg (stmt
, 0);
1689 type
= TREE_TYPE (ptr
);
1690 ptrval
= get_value_for_expr (ptr
, true);
1694 tree lhs
= gimple_call_lhs (stmt
);
1695 type
= TREE_TYPE (lhs
);
1698 if (ptrval
.lattice_val
== UNDEFINED
)
1700 gcc_assert ((ptrval
.lattice_val
== CONSTANT
1701 && TREE_CODE (ptrval
.value
) == INTEGER_CST
)
1702 || wi::sext (ptrval
.mask
, TYPE_PRECISION (type
)) == -1);
1703 if (attr
== NULL_TREE
)
1705 /* Get aligni and misaligni from __builtin_assume_aligned. */
1706 align
= gimple_call_arg (stmt
, 1);
1707 if (!tree_fits_uhwi_p (align
))
1709 aligni
= tree_to_uhwi (align
);
1710 if (gimple_call_num_args (stmt
) > 2)
1712 misalign
= gimple_call_arg (stmt
, 2);
1713 if (!tree_fits_uhwi_p (misalign
))
1715 misaligni
= tree_to_uhwi (misalign
);
1720 /* Get aligni and misaligni from assume_aligned or
1721 alloc_align attributes. */
1722 if (TREE_VALUE (attr
) == NULL_TREE
)
1724 attr
= TREE_VALUE (attr
);
1725 align
= TREE_VALUE (attr
);
1726 if (!tree_fits_uhwi_p (align
))
1728 aligni
= tree_to_uhwi (align
);
1731 if (aligni
== 0 || aligni
> gimple_call_num_args (stmt
))
1733 align
= gimple_call_arg (stmt
, aligni
- 1);
1734 if (!tree_fits_uhwi_p (align
))
1736 aligni
= tree_to_uhwi (align
);
1738 else if (TREE_CHAIN (attr
) && TREE_VALUE (TREE_CHAIN (attr
)))
1740 misalign
= TREE_VALUE (TREE_CHAIN (attr
));
1741 if (!tree_fits_uhwi_p (misalign
))
1743 misaligni
= tree_to_uhwi (misalign
);
1746 if (aligni
<= 1 || (aligni
& (aligni
- 1)) != 0 || misaligni
>= aligni
)
1749 align
= build_int_cst_type (type
, -aligni
);
1750 alignval
= get_value_for_expr (align
, true);
1751 bit_value_binop (BIT_AND_EXPR
, TYPE_SIGN (type
), TYPE_PRECISION (type
), &value
, &mask
,
1752 TYPE_SIGN (type
), TYPE_PRECISION (type
), value_to_wide_int (ptrval
), ptrval
.mask
,
1753 TYPE_SIGN (type
), TYPE_PRECISION (type
), value_to_wide_int (alignval
), alignval
.mask
);
1755 if (wi::sext (mask
, TYPE_PRECISION (type
)) != -1)
1757 val
.lattice_val
= CONSTANT
;
1759 gcc_assert ((mask
.to_uhwi () & (aligni
- 1)) == 0);
1760 gcc_assert ((value
.to_uhwi () & (aligni
- 1)) == 0);
1762 /* ??? Delay building trees here. */
1763 val
.value
= wide_int_to_tree (type
, value
);
1767 val
.lattice_val
= VARYING
;
1768 val
.value
= NULL_TREE
;
1774 /* Evaluate statement STMT.
1775 Valid only for assignments, calls, conditionals, and switches. */
1777 static ccp_prop_value_t
1778 evaluate_stmt (gimple
*stmt
)
1780 ccp_prop_value_t val
;
1781 tree simplified
= NULL_TREE
;
1782 ccp_lattice_t likelyvalue
= likely_value (stmt
);
1783 bool is_constant
= false;
1786 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1788 fprintf (dump_file
, "which is likely ");
1789 switch (likelyvalue
)
1792 fprintf (dump_file
, "CONSTANT");
1795 fprintf (dump_file
, "UNDEFINED");
1798 fprintf (dump_file
, "VARYING");
1802 fprintf (dump_file
, "\n");
1805 /* If the statement is likely to have a CONSTANT result, then try
1806 to fold the statement to determine the constant value. */
1807 /* FIXME. This is the only place that we call ccp_fold.
1808 Since likely_value never returns CONSTANT for calls, we will
1809 not attempt to fold them, including builtins that may profit. */
1810 if (likelyvalue
== CONSTANT
)
1812 fold_defer_overflow_warnings ();
1813 simplified
= ccp_fold (stmt
);
1815 && TREE_CODE (simplified
) == SSA_NAME
)
1817 /* We may not use values of something that may be simulated again,
1818 see valueize_op_1. */
1819 if (SSA_NAME_IS_DEFAULT_DEF (simplified
)
1820 || ! prop_simulate_again_p (SSA_NAME_DEF_STMT (simplified
)))
1822 ccp_prop_value_t
*val
= get_value (simplified
);
1823 if (val
&& val
->lattice_val
!= VARYING
)
1825 fold_undefer_overflow_warnings (true, stmt
, 0);
1830 /* We may also not place a non-valueized copy in the lattice
1831 as that might become stale if we never re-visit this stmt. */
1832 simplified
= NULL_TREE
;
1834 is_constant
= simplified
&& is_gimple_min_invariant (simplified
);
1835 fold_undefer_overflow_warnings (is_constant
, stmt
, 0);
1838 /* The statement produced a constant value. */
1839 val
.lattice_val
= CONSTANT
;
1840 val
.value
= simplified
;
1845 /* If the statement is likely to have a VARYING result, then do not
1846 bother folding the statement. */
1847 else if (likelyvalue
== VARYING
)
1849 enum gimple_code code
= gimple_code (stmt
);
1850 if (code
== GIMPLE_ASSIGN
)
1852 enum tree_code subcode
= gimple_assign_rhs_code (stmt
);
1854 /* Other cases cannot satisfy is_gimple_min_invariant
1856 if (get_gimple_rhs_class (subcode
) == GIMPLE_SINGLE_RHS
)
1857 simplified
= gimple_assign_rhs1 (stmt
);
1859 else if (code
== GIMPLE_SWITCH
)
1860 simplified
= gimple_switch_index (as_a
<gswitch
*> (stmt
));
1862 /* These cannot satisfy is_gimple_min_invariant without folding. */
1863 gcc_assert (code
== GIMPLE_CALL
|| code
== GIMPLE_COND
);
1864 is_constant
= simplified
&& is_gimple_min_invariant (simplified
);
1867 /* The statement produced a constant value. */
1868 val
.lattice_val
= CONSTANT
;
1869 val
.value
= simplified
;
1873 /* If the statement result is likely UNDEFINED, make it so. */
1874 else if (likelyvalue
== UNDEFINED
)
1876 val
.lattice_val
= UNDEFINED
;
1877 val
.value
= NULL_TREE
;
1882 /* Resort to simplification for bitwise tracking. */
1883 if (flag_tree_bit_ccp
1884 && (likelyvalue
== CONSTANT
|| is_gimple_call (stmt
)
1885 || (gimple_assign_single_p (stmt
)
1886 && gimple_assign_rhs_code (stmt
) == ADDR_EXPR
))
1889 enum gimple_code code
= gimple_code (stmt
);
1890 val
.lattice_val
= VARYING
;
1891 val
.value
= NULL_TREE
;
1893 if (code
== GIMPLE_ASSIGN
)
1895 enum tree_code subcode
= gimple_assign_rhs_code (stmt
);
1896 tree rhs1
= gimple_assign_rhs1 (stmt
);
1897 tree lhs
= gimple_assign_lhs (stmt
);
1898 if ((INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
1899 || POINTER_TYPE_P (TREE_TYPE (lhs
)))
1900 && (INTEGRAL_TYPE_P (TREE_TYPE (rhs1
))
1901 || POINTER_TYPE_P (TREE_TYPE (rhs1
))))
1902 switch (get_gimple_rhs_class (subcode
))
1904 case GIMPLE_SINGLE_RHS
:
1905 val
= get_value_for_expr (rhs1
, true);
1908 case GIMPLE_UNARY_RHS
:
1909 val
= bit_value_unop (subcode
, TREE_TYPE (lhs
), rhs1
);
1912 case GIMPLE_BINARY_RHS
:
1913 val
= bit_value_binop (subcode
, TREE_TYPE (lhs
), rhs1
,
1914 gimple_assign_rhs2 (stmt
));
1920 else if (code
== GIMPLE_COND
)
1922 enum tree_code code
= gimple_cond_code (stmt
);
1923 tree rhs1
= gimple_cond_lhs (stmt
);
1924 tree rhs2
= gimple_cond_rhs (stmt
);
1925 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1
))
1926 || POINTER_TYPE_P (TREE_TYPE (rhs1
)))
1927 val
= bit_value_binop (code
, TREE_TYPE (rhs1
), rhs1
, rhs2
);
1929 else if (gimple_call_builtin_p (stmt
, BUILT_IN_NORMAL
))
1931 tree fndecl
= gimple_call_fndecl (stmt
);
1932 switch (DECL_FUNCTION_CODE (fndecl
))
1934 case BUILT_IN_MALLOC
:
1935 case BUILT_IN_REALLOC
:
1936 case BUILT_IN_CALLOC
:
1937 case BUILT_IN_STRDUP
:
1938 case BUILT_IN_STRNDUP
:
1939 val
.lattice_val
= CONSTANT
;
1940 val
.value
= build_int_cst (TREE_TYPE (gimple_get_lhs (stmt
)), 0);
1941 val
.mask
= ~((HOST_WIDE_INT
) MALLOC_ABI_ALIGNMENT
1942 / BITS_PER_UNIT
- 1);
1945 CASE_BUILT_IN_ALLOCA
:
1946 align
= (DECL_FUNCTION_CODE (fndecl
) == BUILT_IN_ALLOCA
1948 : TREE_INT_CST_LOW (gimple_call_arg (stmt
, 1)));
1949 val
.lattice_val
= CONSTANT
;
1950 val
.value
= build_int_cst (TREE_TYPE (gimple_get_lhs (stmt
)), 0);
1951 val
.mask
= ~((HOST_WIDE_INT
) align
/ BITS_PER_UNIT
- 1);
1954 /* These builtins return their first argument, unmodified. */
1955 case BUILT_IN_MEMCPY
:
1956 case BUILT_IN_MEMMOVE
:
1957 case BUILT_IN_MEMSET
:
1958 case BUILT_IN_STRCPY
:
1959 case BUILT_IN_STRNCPY
:
1960 case BUILT_IN_MEMCPY_CHK
:
1961 case BUILT_IN_MEMMOVE_CHK
:
1962 case BUILT_IN_MEMSET_CHK
:
1963 case BUILT_IN_STRCPY_CHK
:
1964 case BUILT_IN_STRNCPY_CHK
:
1965 val
= get_value_for_expr (gimple_call_arg (stmt
, 0), true);
1968 case BUILT_IN_ASSUME_ALIGNED
:
1969 val
= bit_value_assume_aligned (stmt
, NULL_TREE
, val
, false);
1972 case BUILT_IN_ALIGNED_ALLOC
:
1974 tree align
= get_constant_value (gimple_call_arg (stmt
, 0));
1976 && tree_fits_uhwi_p (align
))
1978 unsigned HOST_WIDE_INT aligni
= tree_to_uhwi (align
);
1980 /* align must be power-of-two */
1981 && (aligni
& (aligni
- 1)) == 0)
1983 val
.lattice_val
= CONSTANT
;
1984 val
.value
= build_int_cst (ptr_type_node
, 0);
1991 case BUILT_IN_BSWAP16
:
1992 case BUILT_IN_BSWAP32
:
1993 case BUILT_IN_BSWAP64
:
1994 val
= get_value_for_expr (gimple_call_arg (stmt
, 0), true);
1995 if (val
.lattice_val
== UNDEFINED
)
1997 else if (val
.lattice_val
== CONSTANT
1999 && TREE_CODE (val
.value
) == INTEGER_CST
)
2001 tree type
= TREE_TYPE (gimple_call_lhs (stmt
));
2002 int prec
= TYPE_PRECISION (type
);
2003 wide_int wval
= wi::to_wide (val
.value
);
2005 = wide_int_to_tree (type
,
2006 wide_int::from (wval
, prec
,
2007 UNSIGNED
).bswap ());
2009 = widest_int::from (wide_int::from (val
.mask
, prec
,
2012 if (wi::sext (val
.mask
, prec
) != -1)
2015 val
.lattice_val
= VARYING
;
2016 val
.value
= NULL_TREE
;
2023 if (is_gimple_call (stmt
) && gimple_call_lhs (stmt
))
2025 tree fntype
= gimple_call_fntype (stmt
);
2028 tree attrs
= lookup_attribute ("assume_aligned",
2029 TYPE_ATTRIBUTES (fntype
));
2031 val
= bit_value_assume_aligned (stmt
, attrs
, val
, false);
2032 attrs
= lookup_attribute ("alloc_align",
2033 TYPE_ATTRIBUTES (fntype
));
2035 val
= bit_value_assume_aligned (stmt
, attrs
, val
, true);
2038 is_constant
= (val
.lattice_val
== CONSTANT
);
2041 if (flag_tree_bit_ccp
2042 && ((is_constant
&& TREE_CODE (val
.value
) == INTEGER_CST
)
2044 && gimple_get_lhs (stmt
)
2045 && TREE_CODE (gimple_get_lhs (stmt
)) == SSA_NAME
)
2047 tree lhs
= gimple_get_lhs (stmt
);
2048 wide_int nonzero_bits
= get_nonzero_bits (lhs
);
2049 if (nonzero_bits
!= -1)
2053 val
.lattice_val
= CONSTANT
;
2054 val
.value
= build_zero_cst (TREE_TYPE (lhs
));
2055 val
.mask
= extend_mask (nonzero_bits
, TYPE_SIGN (TREE_TYPE (lhs
)));
2060 if (wi::bit_and_not (wi::to_wide (val
.value
), nonzero_bits
) != 0)
2061 val
.value
= wide_int_to_tree (TREE_TYPE (lhs
),
2063 & wi::to_wide (val
.value
));
2064 if (nonzero_bits
== 0)
2067 val
.mask
= val
.mask
& extend_mask (nonzero_bits
,
2068 TYPE_SIGN (TREE_TYPE (lhs
)));
2073 /* The statement produced a nonconstant value. */
2076 /* The statement produced a copy. */
2077 if (simplified
&& TREE_CODE (simplified
) == SSA_NAME
2078 && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (simplified
))
2080 val
.lattice_val
= CONSTANT
;
2081 val
.value
= simplified
;
2084 /* The statement is VARYING. */
2087 val
.lattice_val
= VARYING
;
2088 val
.value
= NULL_TREE
;
2096 typedef hash_table
<nofree_ptr_hash
<gimple
> > gimple_htab
;
2098 /* Given a BUILT_IN_STACK_SAVE value SAVED_VAL, insert a clobber of VAR before
2099 each matching BUILT_IN_STACK_RESTORE. Mark visited phis in VISITED. */
2102 insert_clobber_before_stack_restore (tree saved_val
, tree var
,
2103 gimple_htab
**visited
)
2106 gassign
*clobber_stmt
;
2108 imm_use_iterator iter
;
2109 gimple_stmt_iterator i
;
2112 FOR_EACH_IMM_USE_STMT (stmt
, iter
, saved_val
)
2113 if (gimple_call_builtin_p (stmt
, BUILT_IN_STACK_RESTORE
))
2115 clobber
= build_clobber (TREE_TYPE (var
));
2116 clobber_stmt
= gimple_build_assign (var
, clobber
);
2118 i
= gsi_for_stmt (stmt
);
2119 gsi_insert_before (&i
, clobber_stmt
, GSI_SAME_STMT
);
2121 else if (gimple_code (stmt
) == GIMPLE_PHI
)
2124 *visited
= new gimple_htab (10);
2126 slot
= (*visited
)->find_slot (stmt
, INSERT
);
2131 insert_clobber_before_stack_restore (gimple_phi_result (stmt
), var
,
2134 else if (gimple_assign_ssa_name_copy_p (stmt
))
2135 insert_clobber_before_stack_restore (gimple_assign_lhs (stmt
), var
,
2139 /* Advance the iterator to the previous non-debug gimple statement in the same
2140 or dominating basic block. */
2143 gsi_prev_dom_bb_nondebug (gimple_stmt_iterator
*i
)
2147 gsi_prev_nondebug (i
);
2148 while (gsi_end_p (*i
))
2150 dom
= get_immediate_dominator (CDI_DOMINATORS
, i
->bb
);
2151 if (dom
== NULL
|| dom
== ENTRY_BLOCK_PTR_FOR_FN (cfun
))
2154 *i
= gsi_last_bb (dom
);
2158 /* Find a BUILT_IN_STACK_SAVE dominating gsi_stmt (I), and insert
2159 a clobber of VAR before each matching BUILT_IN_STACK_RESTORE.
2161 It is possible that BUILT_IN_STACK_SAVE cannot be found in a dominator when
2162 a previous pass (such as DOM) duplicated it along multiple paths to a BB.
2163 In that case the function gives up without inserting the clobbers. */
2166 insert_clobbers_for_var (gimple_stmt_iterator i
, tree var
)
2170 gimple_htab
*visited
= NULL
;
2172 for (; !gsi_end_p (i
); gsi_prev_dom_bb_nondebug (&i
))
2174 stmt
= gsi_stmt (i
);
2176 if (!gimple_call_builtin_p (stmt
, BUILT_IN_STACK_SAVE
))
2179 saved_val
= gimple_call_lhs (stmt
);
2180 if (saved_val
== NULL_TREE
)
2183 insert_clobber_before_stack_restore (saved_val
, var
, &visited
);
2190 /* Detects a __builtin_alloca_with_align with constant size argument. Declares
2191 fixed-size array and returns the address, if found, otherwise returns
2195 fold_builtin_alloca_with_align (gimple
*stmt
)
2197 unsigned HOST_WIDE_INT size
, threshold
, n_elem
;
2198 tree lhs
, arg
, block
, var
, elem_type
, array_type
;
2201 lhs
= gimple_call_lhs (stmt
);
2202 if (lhs
== NULL_TREE
)
2205 /* Detect constant argument. */
2206 arg
= get_constant_value (gimple_call_arg (stmt
, 0));
2207 if (arg
== NULL_TREE
2208 || TREE_CODE (arg
) != INTEGER_CST
2209 || !tree_fits_uhwi_p (arg
))
2212 size
= tree_to_uhwi (arg
);
2214 /* Heuristic: don't fold large allocas. */
2215 threshold
= (unsigned HOST_WIDE_INT
)param_large_stack_frame
;
2216 /* In case the alloca is located at function entry, it has the same lifetime
2217 as a declared array, so we allow a larger size. */
2218 block
= gimple_block (stmt
);
2219 if (!(cfun
->after_inlining
2221 && TREE_CODE (BLOCK_SUPERCONTEXT (block
)) == FUNCTION_DECL
))
2223 if (size
> threshold
)
2226 /* We have to be able to move points-to info. We used to assert
2227 that we can but IPA PTA might end up with two UIDs here
2228 as it might need to handle more than one instance being
2229 live at the same time. Instead of trying to detect this case
2230 (using the first UID would be OK) just give up for now. */
2231 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (lhs
);
2235 && !pt_solution_singleton_or_null_p (&pi
->pt
, &uid
))
2238 /* Declare array. */
2239 elem_type
= build_nonstandard_integer_type (BITS_PER_UNIT
, 1);
2240 n_elem
= size
* 8 / BITS_PER_UNIT
;
2241 array_type
= build_array_type_nelts (elem_type
, n_elem
);
2243 if (tree ssa_name
= SSA_NAME_IDENTIFIER (lhs
))
2245 /* Give the temporary a name derived from the name of the VLA
2246 declaration so it can be referenced in diagnostics. */
2247 const char *name
= IDENTIFIER_POINTER (ssa_name
);
2248 var
= create_tmp_var (array_type
, name
);
2251 var
= create_tmp_var (array_type
);
2253 if (gimple
*lhsdef
= SSA_NAME_DEF_STMT (lhs
))
2255 /* Set the temporary's location to that of the VLA declaration
2256 so it can be pointed to in diagnostics. */
2257 location_t loc
= gimple_location (lhsdef
);
2258 DECL_SOURCE_LOCATION (var
) = loc
;
2261 SET_DECL_ALIGN (var
, TREE_INT_CST_LOW (gimple_call_arg (stmt
, 1)));
2263 SET_DECL_PT_UID (var
, uid
);
2265 /* Fold alloca to the address of the array. */
2266 return fold_convert (TREE_TYPE (lhs
), build_fold_addr_expr (var
));
2269 /* Fold the stmt at *GSI with CCP specific information that propagating
2270 and regular folding does not catch. */
2273 ccp_folder::fold_stmt (gimple_stmt_iterator
*gsi
)
2275 gimple
*stmt
= gsi_stmt (*gsi
);
2277 switch (gimple_code (stmt
))
2281 gcond
*cond_stmt
= as_a
<gcond
*> (stmt
);
2282 ccp_prop_value_t val
;
2283 /* Statement evaluation will handle type mismatches in constants
2284 more gracefully than the final propagation. This allows us to
2285 fold more conditionals here. */
2286 val
= evaluate_stmt (stmt
);
2287 if (val
.lattice_val
!= CONSTANT
2293 fprintf (dump_file
, "Folding predicate ");
2294 print_gimple_expr (dump_file
, stmt
, 0);
2295 fprintf (dump_file
, " to ");
2296 print_generic_expr (dump_file
, val
.value
);
2297 fprintf (dump_file
, "\n");
2300 if (integer_zerop (val
.value
))
2301 gimple_cond_make_false (cond_stmt
);
2303 gimple_cond_make_true (cond_stmt
);
2310 tree lhs
= gimple_call_lhs (stmt
);
2311 int flags
= gimple_call_flags (stmt
);
2314 bool changed
= false;
2317 /* If the call was folded into a constant make sure it goes
2318 away even if we cannot propagate into all uses because of
2321 && TREE_CODE (lhs
) == SSA_NAME
2322 && (val
= get_constant_value (lhs
))
2323 /* Don't optimize away calls that have side-effects. */
2324 && (flags
& (ECF_CONST
|ECF_PURE
)) != 0
2325 && (flags
& ECF_LOOPING_CONST_OR_PURE
) == 0)
2327 tree new_rhs
= unshare_expr (val
);
2329 if (!useless_type_conversion_p (TREE_TYPE (lhs
),
2330 TREE_TYPE (new_rhs
)))
2331 new_rhs
= fold_convert (TREE_TYPE (lhs
), new_rhs
);
2332 res
= update_call_from_tree (gsi
, new_rhs
);
2337 /* Internal calls provide no argument types, so the extra laxity
2338 for normal calls does not apply. */
2339 if (gimple_call_internal_p (stmt
))
2342 /* The heuristic of fold_builtin_alloca_with_align differs before and
2343 after inlining, so we don't require the arg to be changed into a
2344 constant for folding, but just to be constant. */
2345 if (gimple_call_builtin_p (stmt
, BUILT_IN_ALLOCA_WITH_ALIGN
)
2346 || gimple_call_builtin_p (stmt
, BUILT_IN_ALLOCA_WITH_ALIGN_AND_MAX
))
2348 tree new_rhs
= fold_builtin_alloca_with_align (stmt
);
2351 bool res
= update_call_from_tree (gsi
, new_rhs
);
2352 tree var
= TREE_OPERAND (TREE_OPERAND (new_rhs
, 0),0);
2354 insert_clobbers_for_var (*gsi
, var
);
2359 /* If there's no extra info from an assume_aligned call,
2360 drop it so it doesn't act as otherwise useless dataflow
2362 if (gimple_call_builtin_p (stmt
, BUILT_IN_ASSUME_ALIGNED
))
2364 tree ptr
= gimple_call_arg (stmt
, 0);
2365 ccp_prop_value_t ptrval
= get_value_for_expr (ptr
, true);
2366 if (ptrval
.lattice_val
== CONSTANT
2367 && TREE_CODE (ptrval
.value
) == INTEGER_CST
2368 && ptrval
.mask
!= 0)
2370 ccp_prop_value_t val
2371 = bit_value_assume_aligned (stmt
, NULL_TREE
, ptrval
, false);
2372 unsigned int ptralign
= least_bit_hwi (ptrval
.mask
.to_uhwi ());
2373 unsigned int align
= least_bit_hwi (val
.mask
.to_uhwi ());
2374 if (ptralign
== align
2375 && ((TREE_INT_CST_LOW (ptrval
.value
) & (align
- 1))
2376 == (TREE_INT_CST_LOW (val
.value
) & (align
- 1))))
2378 bool res
= update_call_from_tree (gsi
, ptr
);
2385 /* Propagate into the call arguments. Compared to replace_uses_in
2386 this can use the argument slot types for type verification
2387 instead of the current argument type. We also can safely
2388 drop qualifiers here as we are dealing with constants anyway. */
2389 argt
= TYPE_ARG_TYPES (gimple_call_fntype (stmt
));
2390 for (i
= 0; i
< gimple_call_num_args (stmt
) && argt
;
2391 ++i
, argt
= TREE_CHAIN (argt
))
2393 tree arg
= gimple_call_arg (stmt
, i
);
2394 if (TREE_CODE (arg
) == SSA_NAME
2395 && (val
= get_constant_value (arg
))
2396 && useless_type_conversion_p
2397 (TYPE_MAIN_VARIANT (TREE_VALUE (argt
)),
2398 TYPE_MAIN_VARIANT (TREE_TYPE (val
))))
2400 gimple_call_set_arg (stmt
, i
, unshare_expr (val
));
2410 tree lhs
= gimple_assign_lhs (stmt
);
2413 /* If we have a load that turned out to be constant replace it
2414 as we cannot propagate into all uses in all cases. */
2415 if (gimple_assign_single_p (stmt
)
2416 && TREE_CODE (lhs
) == SSA_NAME
2417 && (val
= get_constant_value (lhs
)))
2419 tree rhs
= unshare_expr (val
);
2420 if (!useless_type_conversion_p (TREE_TYPE (lhs
), TREE_TYPE (rhs
)))
2421 rhs
= fold_build1 (VIEW_CONVERT_EXPR
, TREE_TYPE (lhs
), rhs
);
2422 gimple_assign_set_rhs_from_tree (gsi
, rhs
);
2434 /* Visit the assignment statement STMT. Set the value of its LHS to the
2435 value computed by the RHS and store LHS in *OUTPUT_P. If STMT
2436 creates virtual definitions, set the value of each new name to that
2437 of the RHS (if we can derive a constant out of the RHS).
2438 Value-returning call statements also perform an assignment, and
2439 are handled here. */
2441 static enum ssa_prop_result
2442 visit_assignment (gimple
*stmt
, tree
*output_p
)
2444 ccp_prop_value_t val
;
2445 enum ssa_prop_result retval
= SSA_PROP_NOT_INTERESTING
;
2447 tree lhs
= gimple_get_lhs (stmt
);
2448 if (TREE_CODE (lhs
) == SSA_NAME
)
2450 /* Evaluate the statement, which could be
2451 either a GIMPLE_ASSIGN or a GIMPLE_CALL. */
2452 val
= evaluate_stmt (stmt
);
2454 /* If STMT is an assignment to an SSA_NAME, we only have one
2456 if (set_lattice_value (lhs
, &val
))
2459 if (val
.lattice_val
== VARYING
)
2460 retval
= SSA_PROP_VARYING
;
2462 retval
= SSA_PROP_INTERESTING
;
2470 /* Visit the conditional statement STMT. Return SSA_PROP_INTERESTING
2471 if it can determine which edge will be taken. Otherwise, return
2472 SSA_PROP_VARYING. */
2474 static enum ssa_prop_result
2475 visit_cond_stmt (gimple
*stmt
, edge
*taken_edge_p
)
2477 ccp_prop_value_t val
;
2480 block
= gimple_bb (stmt
);
2481 val
= evaluate_stmt (stmt
);
2482 if (val
.lattice_val
!= CONSTANT
2484 return SSA_PROP_VARYING
;
2486 /* Find which edge out of the conditional block will be taken and add it
2487 to the worklist. If no single edge can be determined statically,
2488 return SSA_PROP_VARYING to feed all the outgoing edges to the
2489 propagation engine. */
2490 *taken_edge_p
= find_taken_edge (block
, val
.value
);
2492 return SSA_PROP_INTERESTING
;
2494 return SSA_PROP_VARYING
;
2498 /* Evaluate statement STMT. If the statement produces an output value and
2499 its evaluation changes the lattice value of its output, return
2500 SSA_PROP_INTERESTING and set *OUTPUT_P to the SSA_NAME holding the
2503 If STMT is a conditional branch and we can determine its truth
2504 value, set *TAKEN_EDGE_P accordingly. If STMT produces a varying
2505 value, return SSA_PROP_VARYING. */
2507 enum ssa_prop_result
2508 ccp_propagate::visit_stmt (gimple
*stmt
, edge
*taken_edge_p
, tree
*output_p
)
2513 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2515 fprintf (dump_file
, "\nVisiting statement:\n");
2516 print_gimple_stmt (dump_file
, stmt
, 0, dump_flags
);
2519 switch (gimple_code (stmt
))
2522 /* If the statement is an assignment that produces a single
2523 output value, evaluate its RHS to see if the lattice value of
2524 its output has changed. */
2525 return visit_assignment (stmt
, output_p
);
2528 /* A value-returning call also performs an assignment. */
2529 if (gimple_call_lhs (stmt
) != NULL_TREE
)
2530 return visit_assignment (stmt
, output_p
);
2535 /* If STMT is a conditional branch, see if we can determine
2536 which branch will be taken. */
2537 /* FIXME. It appears that we should be able to optimize
2538 computed GOTOs here as well. */
2539 return visit_cond_stmt (stmt
, taken_edge_p
);
2545 /* Any other kind of statement is not interesting for constant
2546 propagation and, therefore, not worth simulating. */
2547 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2548 fprintf (dump_file
, "No interesting values produced. Marked VARYING.\n");
2550 /* Definitions made by statements other than assignments to
2551 SSA_NAMEs represent unknown modifications to their outputs.
2552 Mark them VARYING. */
2553 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, iter
, SSA_OP_ALL_DEFS
)
2554 set_value_varying (def
);
2556 return SSA_PROP_VARYING
;
2560 /* Main entry point for SSA Conditional Constant Propagation. If NONZERO_P,
2561 record nonzero bits. */
2564 do_ssa_ccp (bool nonzero_p
)
2566 unsigned int todo
= 0;
2567 calculate_dominance_info (CDI_DOMINATORS
);
2570 class ccp_propagate ccp_propagate
;
2571 ccp_propagate
.ssa_propagate ();
2572 if (ccp_finalize (nonzero_p
|| flag_ipa_bit_cp
))
2574 todo
= (TODO_cleanup_cfg
| TODO_update_ssa
);
2576 /* ccp_finalize does not preserve loop-closed ssa. */
2577 loops_state_clear (LOOP_CLOSED_SSA
);
2580 free_dominance_info (CDI_DOMINATORS
);
2587 const pass_data pass_data_ccp
=
2589 GIMPLE_PASS
, /* type */
2591 OPTGROUP_NONE
, /* optinfo_flags */
2592 TV_TREE_CCP
, /* tv_id */
2593 ( PROP_cfg
| PROP_ssa
), /* properties_required */
2594 0, /* properties_provided */
2595 0, /* properties_destroyed */
2596 0, /* todo_flags_start */
2597 TODO_update_address_taken
, /* todo_flags_finish */
2600 class pass_ccp
: public gimple_opt_pass
2603 pass_ccp (gcc::context
*ctxt
)
2604 : gimple_opt_pass (pass_data_ccp
, ctxt
), nonzero_p (false)
2607 /* opt_pass methods: */
2608 opt_pass
* clone () { return new pass_ccp (m_ctxt
); }
2609 void set_pass_param (unsigned int n
, bool param
)
2611 gcc_assert (n
== 0);
2614 virtual bool gate (function
*) { return flag_tree_ccp
!= 0; }
2615 virtual unsigned int execute (function
*) { return do_ssa_ccp (nonzero_p
); }
2618 /* Determines whether the pass instance records nonzero bits. */
2620 }; // class pass_ccp
2625 make_pass_ccp (gcc::context
*ctxt
)
2627 return new pass_ccp (ctxt
);
2632 /* Try to optimize out __builtin_stack_restore. Optimize it out
2633 if there is another __builtin_stack_restore in the same basic
2634 block and no calls or ASM_EXPRs are in between, or if this block's
2635 only outgoing edge is to EXIT_BLOCK and there are no calls or
2636 ASM_EXPRs after this __builtin_stack_restore. */
2639 optimize_stack_restore (gimple_stmt_iterator i
)
2644 basic_block bb
= gsi_bb (i
);
2645 gimple
*call
= gsi_stmt (i
);
2647 if (gimple_code (call
) != GIMPLE_CALL
2648 || gimple_call_num_args (call
) != 1
2649 || TREE_CODE (gimple_call_arg (call
, 0)) != SSA_NAME
2650 || !POINTER_TYPE_P (TREE_TYPE (gimple_call_arg (call
, 0))))
2653 for (gsi_next (&i
); !gsi_end_p (i
); gsi_next (&i
))
2655 stmt
= gsi_stmt (i
);
2656 if (gimple_code (stmt
) == GIMPLE_ASM
)
2658 if (gimple_code (stmt
) != GIMPLE_CALL
)
2661 callee
= gimple_call_fndecl (stmt
);
2663 || !fndecl_built_in_p (callee
, BUILT_IN_NORMAL
)
2664 /* All regular builtins are ok, just obviously not alloca. */
2665 || ALLOCA_FUNCTION_CODE_P (DECL_FUNCTION_CODE (callee
)))
2668 if (fndecl_built_in_p (callee
, BUILT_IN_STACK_RESTORE
))
2669 goto second_stack_restore
;
2675 /* Allow one successor of the exit block, or zero successors. */
2676 switch (EDGE_COUNT (bb
->succs
))
2681 if (single_succ_edge (bb
)->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
2687 second_stack_restore
:
2689 /* If there's exactly one use, then zap the call to __builtin_stack_save.
2690 If there are multiple uses, then the last one should remove the call.
2691 In any case, whether the call to __builtin_stack_save can be removed
2692 or not is irrelevant to removing the call to __builtin_stack_restore. */
2693 if (has_single_use (gimple_call_arg (call
, 0)))
2695 gimple
*stack_save
= SSA_NAME_DEF_STMT (gimple_call_arg (call
, 0));
2696 if (is_gimple_call (stack_save
))
2698 callee
= gimple_call_fndecl (stack_save
);
2699 if (callee
&& fndecl_built_in_p (callee
, BUILT_IN_STACK_SAVE
))
2701 gimple_stmt_iterator stack_save_gsi
;
2704 stack_save_gsi
= gsi_for_stmt (stack_save
);
2705 rhs
= build_int_cst (TREE_TYPE (gimple_call_arg (call
, 0)), 0);
2706 update_call_from_tree (&stack_save_gsi
, rhs
);
2711 /* No effect, so the statement will be deleted. */
2712 return integer_zero_node
;
2715 /* If va_list type is a simple pointer and nothing special is needed,
2716 optimize __builtin_va_start (&ap, 0) into ap = __builtin_next_arg (0),
2717 __builtin_va_end (&ap) out as NOP and __builtin_va_copy into a simple
2718 pointer assignment. */
2721 optimize_stdarg_builtin (gimple
*call
)
2723 tree callee
, lhs
, rhs
, cfun_va_list
;
2724 bool va_list_simple_ptr
;
2725 location_t loc
= gimple_location (call
);
2727 callee
= gimple_call_fndecl (call
);
2729 cfun_va_list
= targetm
.fn_abi_va_list (callee
);
2730 va_list_simple_ptr
= POINTER_TYPE_P (cfun_va_list
)
2731 && (TREE_TYPE (cfun_va_list
) == void_type_node
2732 || TREE_TYPE (cfun_va_list
) == char_type_node
);
2734 switch (DECL_FUNCTION_CODE (callee
))
2736 case BUILT_IN_VA_START
:
2737 if (!va_list_simple_ptr
2738 || targetm
.expand_builtin_va_start
!= NULL
2739 || !builtin_decl_explicit_p (BUILT_IN_NEXT_ARG
))
2742 if (gimple_call_num_args (call
) != 2)
2745 lhs
= gimple_call_arg (call
, 0);
2746 if (!POINTER_TYPE_P (TREE_TYPE (lhs
))
2747 || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs
)))
2748 != TYPE_MAIN_VARIANT (cfun_va_list
))
2751 lhs
= build_fold_indirect_ref_loc (loc
, lhs
);
2752 rhs
= build_call_expr_loc (loc
, builtin_decl_explicit (BUILT_IN_NEXT_ARG
),
2753 1, integer_zero_node
);
2754 rhs
= fold_convert_loc (loc
, TREE_TYPE (lhs
), rhs
);
2755 return build2 (MODIFY_EXPR
, TREE_TYPE (lhs
), lhs
, rhs
);
2757 case BUILT_IN_VA_COPY
:
2758 if (!va_list_simple_ptr
)
2761 if (gimple_call_num_args (call
) != 2)
2764 lhs
= gimple_call_arg (call
, 0);
2765 if (!POINTER_TYPE_P (TREE_TYPE (lhs
))
2766 || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs
)))
2767 != TYPE_MAIN_VARIANT (cfun_va_list
))
2770 lhs
= build_fold_indirect_ref_loc (loc
, lhs
);
2771 rhs
= gimple_call_arg (call
, 1);
2772 if (TYPE_MAIN_VARIANT (TREE_TYPE (rhs
))
2773 != TYPE_MAIN_VARIANT (cfun_va_list
))
2776 rhs
= fold_convert_loc (loc
, TREE_TYPE (lhs
), rhs
);
2777 return build2 (MODIFY_EXPR
, TREE_TYPE (lhs
), lhs
, rhs
);
2779 case BUILT_IN_VA_END
:
2780 /* No effect, so the statement will be deleted. */
2781 return integer_zero_node
;
2788 /* Attemp to make the block of __builtin_unreachable I unreachable by changing
2789 the incoming jumps. Return true if at least one jump was changed. */
2792 optimize_unreachable (gimple_stmt_iterator i
)
2794 basic_block bb
= gsi_bb (i
);
2795 gimple_stmt_iterator gsi
;
2801 if (flag_sanitize
& SANITIZE_UNREACHABLE
)
2804 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
2806 stmt
= gsi_stmt (gsi
);
2808 if (is_gimple_debug (stmt
))
2811 if (glabel
*label_stmt
= dyn_cast
<glabel
*> (stmt
))
2813 /* Verify we do not need to preserve the label. */
2814 if (FORCED_LABEL (gimple_label_label (label_stmt
)))
2820 /* Only handle the case that __builtin_unreachable is the first statement
2821 in the block. We rely on DCE to remove stmts without side-effects
2822 before __builtin_unreachable. */
2823 if (gsi_stmt (gsi
) != gsi_stmt (i
))
2828 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
2830 gsi
= gsi_last_bb (e
->src
);
2831 if (gsi_end_p (gsi
))
2834 stmt
= gsi_stmt (gsi
);
2835 if (gcond
*cond_stmt
= dyn_cast
<gcond
*> (stmt
))
2837 if (e
->flags
& EDGE_TRUE_VALUE
)
2838 gimple_cond_make_false (cond_stmt
);
2839 else if (e
->flags
& EDGE_FALSE_VALUE
)
2840 gimple_cond_make_true (cond_stmt
);
2843 update_stmt (cond_stmt
);
2847 /* Todo: handle other cases. Note that unreachable switch case
2848 statements have already been removed. */
2859 mask_2 = 1 << cnt_1;
2860 _4 = __atomic_fetch_or_* (ptr_6, mask_2, _3);
2863 _4 = ATOMIC_BIT_TEST_AND_SET (ptr_6, cnt_1, 0, _3);
2865 If _5 is only used in _5 != 0 or _5 == 0 comparisons, 1
2866 is passed instead of 0, and the builtin just returns a zero
2867 or 1 value instead of the actual bit.
2868 Similarly for __sync_fetch_and_or_* (without the ", _3" part
2869 in there), and/or if mask_2 is a power of 2 constant.
2870 Similarly for xor instead of or, use ATOMIC_BIT_TEST_AND_COMPLEMENT
2871 in that case. And similarly for and instead of or, except that
2872 the second argument to the builtin needs to be one's complement
2873 of the mask instead of mask. */
2876 optimize_atomic_bit_test_and (gimple_stmt_iterator
*gsip
,
2877 enum internal_fn fn
, bool has_model_arg
,
2880 gimple
*call
= gsi_stmt (*gsip
);
2881 tree lhs
= gimple_call_lhs (call
);
2882 use_operand_p use_p
;
2887 if (!flag_inline_atomics
2889 || !gimple_call_builtin_p (call
, BUILT_IN_NORMAL
)
2891 || SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs
)
2892 || !single_imm_use (lhs
, &use_p
, &use_stmt
)
2893 || !is_gimple_assign (use_stmt
)
2894 || gimple_assign_rhs_code (use_stmt
) != BIT_AND_EXPR
2895 || !gimple_vdef (call
))
2900 case IFN_ATOMIC_BIT_TEST_AND_SET
:
2901 optab
= atomic_bit_test_and_set_optab
;
2903 case IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT
:
2904 optab
= atomic_bit_test_and_complement_optab
;
2906 case IFN_ATOMIC_BIT_TEST_AND_RESET
:
2907 optab
= atomic_bit_test_and_reset_optab
;
2913 if (optab_handler (optab
, TYPE_MODE (TREE_TYPE (lhs
))) == CODE_FOR_nothing
)
2916 mask
= gimple_call_arg (call
, 1);
2917 tree use_lhs
= gimple_assign_lhs (use_stmt
);
2921 if (TREE_CODE (mask
) == INTEGER_CST
)
2923 if (fn
== IFN_ATOMIC_BIT_TEST_AND_RESET
)
2924 mask
= const_unop (BIT_NOT_EXPR
, TREE_TYPE (mask
), mask
);
2925 mask
= fold_convert (TREE_TYPE (lhs
), mask
);
2926 int ibit
= tree_log2 (mask
);
2929 bit
= build_int_cst (TREE_TYPE (lhs
), ibit
);
2931 else if (TREE_CODE (mask
) == SSA_NAME
)
2933 gimple
*g
= SSA_NAME_DEF_STMT (mask
);
2934 if (fn
== IFN_ATOMIC_BIT_TEST_AND_RESET
)
2936 if (!is_gimple_assign (g
)
2937 || gimple_assign_rhs_code (g
) != BIT_NOT_EXPR
)
2939 mask
= gimple_assign_rhs1 (g
);
2940 if (TREE_CODE (mask
) != SSA_NAME
)
2942 g
= SSA_NAME_DEF_STMT (mask
);
2944 if (!is_gimple_assign (g
)
2945 || gimple_assign_rhs_code (g
) != LSHIFT_EXPR
2946 || !integer_onep (gimple_assign_rhs1 (g
)))
2948 bit
= gimple_assign_rhs2 (g
);
2953 if (gimple_assign_rhs1 (use_stmt
) == lhs
)
2955 if (!operand_equal_p (gimple_assign_rhs2 (use_stmt
), mask
, 0))
2958 else if (gimple_assign_rhs2 (use_stmt
) != lhs
2959 || !operand_equal_p (gimple_assign_rhs1 (use_stmt
), mask
, 0))
2962 bool use_bool
= true;
2963 bool has_debug_uses
= false;
2964 imm_use_iterator iter
;
2967 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (use_lhs
))
2969 FOR_EACH_IMM_USE_STMT (g
, iter
, use_lhs
)
2971 enum tree_code code
= ERROR_MARK
;
2972 tree op0
= NULL_TREE
, op1
= NULL_TREE
;
2973 if (is_gimple_debug (g
))
2975 has_debug_uses
= true;
2978 else if (is_gimple_assign (g
))
2979 switch (gimple_assign_rhs_code (g
))
2982 op1
= gimple_assign_rhs1 (g
);
2983 code
= TREE_CODE (op1
);
2984 op0
= TREE_OPERAND (op1
, 0);
2985 op1
= TREE_OPERAND (op1
, 1);
2989 code
= gimple_assign_rhs_code (g
);
2990 op0
= gimple_assign_rhs1 (g
);
2991 op1
= gimple_assign_rhs2 (g
);
2996 else if (gimple_code (g
) == GIMPLE_COND
)
2998 code
= gimple_cond_code (g
);
2999 op0
= gimple_cond_lhs (g
);
3000 op1
= gimple_cond_rhs (g
);
3003 if ((code
== EQ_EXPR
|| code
== NE_EXPR
)
3005 && integer_zerop (op1
))
3007 use_operand_p use_p
;
3009 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
3016 BREAK_FROM_IMM_USE_STMT (iter
);
3019 tree new_lhs
= make_ssa_name (TREE_TYPE (lhs
));
3020 tree flag
= build_int_cst (TREE_TYPE (lhs
), use_bool
);
3022 g
= gimple_build_call_internal (fn
, 4, gimple_call_arg (call
, 0),
3023 bit
, flag
, gimple_call_arg (call
, 2));
3025 g
= gimple_build_call_internal (fn
, 3, gimple_call_arg (call
, 0),
3027 gimple_call_set_lhs (g
, new_lhs
);
3028 gimple_set_location (g
, gimple_location (call
));
3029 gimple_move_vops (g
, call
);
3030 bool throws
= stmt_can_throw_internal (cfun
, call
);
3031 gimple_call_set_nothrow (as_a
<gcall
*> (g
),
3032 gimple_call_nothrow_p (as_a
<gcall
*> (call
)));
3033 gimple_stmt_iterator gsi
= *gsip
;
3034 gsi_insert_after (&gsi
, g
, GSI_NEW_STMT
);
3038 maybe_clean_or_replace_eh_stmt (call
, g
);
3039 if (after
|| (use_bool
&& has_debug_uses
))
3040 e
= find_fallthru_edge (gsi_bb (gsi
)->succs
);
3044 /* The internal function returns the value of the specified bit
3045 before the atomic operation. If we are interested in the value
3046 of the specified bit after the atomic operation (makes only sense
3047 for xor, otherwise the bit content is compile time known),
3048 we need to invert the bit. */
3049 g
= gimple_build_assign (make_ssa_name (TREE_TYPE (lhs
)),
3050 BIT_XOR_EXPR
, new_lhs
,
3051 use_bool
? build_int_cst (TREE_TYPE (lhs
), 1)
3053 new_lhs
= gimple_assign_lhs (g
);
3056 gsi_insert_on_edge_immediate (e
, g
);
3057 gsi
= gsi_for_stmt (g
);
3060 gsi_insert_after (&gsi
, g
, GSI_NEW_STMT
);
3062 if (use_bool
&& has_debug_uses
)
3064 tree temp
= NULL_TREE
;
3065 if (!throws
|| after
|| single_pred_p (e
->dest
))
3067 temp
= make_node (DEBUG_EXPR_DECL
);
3068 DECL_ARTIFICIAL (temp
) = 1;
3069 TREE_TYPE (temp
) = TREE_TYPE (lhs
);
3070 SET_DECL_MODE (temp
, TYPE_MODE (TREE_TYPE (lhs
)));
3071 tree t
= build2 (LSHIFT_EXPR
, TREE_TYPE (lhs
), new_lhs
, bit
);
3072 g
= gimple_build_debug_bind (temp
, t
, g
);
3073 if (throws
&& !after
)
3075 gsi
= gsi_after_labels (e
->dest
);
3076 gsi_insert_before (&gsi
, g
, GSI_SAME_STMT
);
3079 gsi_insert_after (&gsi
, g
, GSI_NEW_STMT
);
3081 FOR_EACH_IMM_USE_STMT (g
, iter
, use_lhs
)
3082 if (is_gimple_debug (g
))
3084 use_operand_p use_p
;
3085 if (temp
== NULL_TREE
)
3086 gimple_debug_bind_reset_value (g
);
3088 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
3089 SET_USE (use_p
, temp
);
3093 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_lhs
)
3094 = SSA_NAME_OCCURS_IN_ABNORMAL_PHI (use_lhs
);
3095 replace_uses_by (use_lhs
, new_lhs
);
3096 gsi
= gsi_for_stmt (use_stmt
);
3097 gsi_remove (&gsi
, true);
3098 release_defs (use_stmt
);
3099 gsi_remove (gsip
, true);
3100 release_ssa_name (lhs
);
3109 Similarly for memset (&a, ..., sizeof (a)); instead of a = {};
3110 and/or memcpy (&b, &a, sizeof (a)); instead of b = a; */
3113 optimize_memcpy (gimple_stmt_iterator
*gsip
, tree dest
, tree src
, tree len
)
3115 gimple
*stmt
= gsi_stmt (*gsip
);
3116 if (gimple_has_volatile_ops (stmt
))
3119 tree vuse
= gimple_vuse (stmt
);
3123 gimple
*defstmt
= SSA_NAME_DEF_STMT (vuse
);
3124 tree src2
= NULL_TREE
, len2
= NULL_TREE
;
3125 poly_int64 offset
, offset2
;
3126 tree val
= integer_zero_node
;
3127 if (gimple_store_p (defstmt
)
3128 && gimple_assign_single_p (defstmt
)
3129 && TREE_CODE (gimple_assign_rhs1 (defstmt
)) == CONSTRUCTOR
3130 && !gimple_clobber_p (defstmt
))
3131 src2
= gimple_assign_lhs (defstmt
);
3132 else if (gimple_call_builtin_p (defstmt
, BUILT_IN_MEMSET
)
3133 && TREE_CODE (gimple_call_arg (defstmt
, 0)) == ADDR_EXPR
3134 && TREE_CODE (gimple_call_arg (defstmt
, 1)) == INTEGER_CST
)
3136 src2
= TREE_OPERAND (gimple_call_arg (defstmt
, 0), 0);
3137 len2
= gimple_call_arg (defstmt
, 2);
3138 val
= gimple_call_arg (defstmt
, 1);
3139 /* For non-0 val, we'd have to transform stmt from assignment
3140 into memset (only if dest is addressable). */
3141 if (!integer_zerop (val
) && is_gimple_assign (stmt
))
3145 if (src2
== NULL_TREE
)
3148 if (len
== NULL_TREE
)
3149 len
= (TREE_CODE (src
) == COMPONENT_REF
3150 ? DECL_SIZE_UNIT (TREE_OPERAND (src
, 1))
3151 : TYPE_SIZE_UNIT (TREE_TYPE (src
)));
3152 if (len2
== NULL_TREE
)
3153 len2
= (TREE_CODE (src2
) == COMPONENT_REF
3154 ? DECL_SIZE_UNIT (TREE_OPERAND (src2
, 1))
3155 : TYPE_SIZE_UNIT (TREE_TYPE (src2
)));
3156 if (len
== NULL_TREE
3157 || !poly_int_tree_p (len
)
3158 || len2
== NULL_TREE
3159 || !poly_int_tree_p (len2
))
3162 src
= get_addr_base_and_unit_offset (src
, &offset
);
3163 src2
= get_addr_base_and_unit_offset (src2
, &offset2
);
3164 if (src
== NULL_TREE
3165 || src2
== NULL_TREE
3166 || maybe_lt (offset
, offset2
))
3169 if (!operand_equal_p (src
, src2
, 0))
3172 /* [ src + offset2, src + offset2 + len2 - 1 ] is set to val.
3174 [ src + offset, src + offset + len - 1 ] is a subset of that. */
3175 if (maybe_gt (wi::to_poly_offset (len
) + (offset
- offset2
),
3176 wi::to_poly_offset (len2
)))
3179 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3181 fprintf (dump_file
, "Simplified\n ");
3182 print_gimple_stmt (dump_file
, stmt
, 0, dump_flags
);
3183 fprintf (dump_file
, "after previous\n ");
3184 print_gimple_stmt (dump_file
, defstmt
, 0, dump_flags
);
3187 /* For simplicity, don't change the kind of the stmt,
3188 turn dest = src; into dest = {}; and memcpy (&dest, &src, len);
3189 into memset (&dest, val, len);
3190 In theory we could change dest = src into memset if dest
3191 is addressable (maybe beneficial if val is not 0), or
3192 memcpy (&dest, &src, len) into dest = {} if len is the size
3193 of dest, dest isn't volatile. */
3194 if (is_gimple_assign (stmt
))
3196 tree ctor
= build_constructor (TREE_TYPE (dest
), NULL
);
3197 gimple_assign_set_rhs_from_tree (gsip
, ctor
);
3200 else /* If stmt is memcpy, transform it into memset. */
3202 gcall
*call
= as_a
<gcall
*> (stmt
);
3203 tree fndecl
= builtin_decl_implicit (BUILT_IN_MEMSET
);
3204 gimple_call_set_fndecl (call
, fndecl
);
3205 gimple_call_set_fntype (call
, TREE_TYPE (fndecl
));
3206 gimple_call_set_arg (call
, 1, val
);
3210 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3212 fprintf (dump_file
, "into\n ");
3213 print_gimple_stmt (dump_file
, stmt
, 0, dump_flags
);
3217 /* A simple pass that attempts to fold all builtin functions. This pass
3218 is run after we've propagated as many constants as we can. */
3222 const pass_data pass_data_fold_builtins
=
3224 GIMPLE_PASS
, /* type */
3226 OPTGROUP_NONE
, /* optinfo_flags */
3227 TV_NONE
, /* tv_id */
3228 ( PROP_cfg
| PROP_ssa
), /* properties_required */
3229 0, /* properties_provided */
3230 0, /* properties_destroyed */
3231 0, /* todo_flags_start */
3232 TODO_update_ssa
, /* todo_flags_finish */
3235 class pass_fold_builtins
: public gimple_opt_pass
3238 pass_fold_builtins (gcc::context
*ctxt
)
3239 : gimple_opt_pass (pass_data_fold_builtins
, ctxt
)
3242 /* opt_pass methods: */
3243 opt_pass
* clone () { return new pass_fold_builtins (m_ctxt
); }
3244 virtual unsigned int execute (function
*);
3246 }; // class pass_fold_builtins
3249 pass_fold_builtins::execute (function
*fun
)
3251 bool cfg_changed
= false;
3253 unsigned int todoflags
= 0;
3255 FOR_EACH_BB_FN (bb
, fun
)
3257 gimple_stmt_iterator i
;
3258 for (i
= gsi_start_bb (bb
); !gsi_end_p (i
); )
3260 gimple
*stmt
, *old_stmt
;
3262 enum built_in_function fcode
;
3264 stmt
= gsi_stmt (i
);
3266 if (gimple_code (stmt
) != GIMPLE_CALL
)
3268 /* Remove all *ssaname_N ={v} {CLOBBER}; stmts,
3269 after the last GIMPLE DSE they aren't needed and might
3270 unnecessarily keep the SSA_NAMEs live. */
3271 if (gimple_clobber_p (stmt
))
3273 tree lhs
= gimple_assign_lhs (stmt
);
3274 if (TREE_CODE (lhs
) == MEM_REF
3275 && TREE_CODE (TREE_OPERAND (lhs
, 0)) == SSA_NAME
)
3277 unlink_stmt_vdef (stmt
);
3278 gsi_remove (&i
, true);
3279 release_defs (stmt
);
3283 else if (gimple_assign_load_p (stmt
) && gimple_store_p (stmt
))
3284 optimize_memcpy (&i
, gimple_assign_lhs (stmt
),
3285 gimple_assign_rhs1 (stmt
), NULL_TREE
);
3290 callee
= gimple_call_fndecl (stmt
);
3291 if (!callee
|| !fndecl_built_in_p (callee
, BUILT_IN_NORMAL
))
3297 fcode
= DECL_FUNCTION_CODE (callee
);
3302 tree result
= NULL_TREE
;
3303 switch (DECL_FUNCTION_CODE (callee
))
3305 case BUILT_IN_CONSTANT_P
:
3306 /* Resolve __builtin_constant_p. If it hasn't been
3307 folded to integer_one_node by now, it's fairly
3308 certain that the value simply isn't constant. */
3309 result
= integer_zero_node
;
3312 case BUILT_IN_ASSUME_ALIGNED
:
3313 /* Remove __builtin_assume_aligned. */
3314 result
= gimple_call_arg (stmt
, 0);
3317 case BUILT_IN_STACK_RESTORE
:
3318 result
= optimize_stack_restore (i
);
3324 case BUILT_IN_UNREACHABLE
:
3325 if (optimize_unreachable (i
))
3329 case BUILT_IN_ATOMIC_FETCH_OR_1
:
3330 case BUILT_IN_ATOMIC_FETCH_OR_2
:
3331 case BUILT_IN_ATOMIC_FETCH_OR_4
:
3332 case BUILT_IN_ATOMIC_FETCH_OR_8
:
3333 case BUILT_IN_ATOMIC_FETCH_OR_16
:
3334 optimize_atomic_bit_test_and (&i
,
3335 IFN_ATOMIC_BIT_TEST_AND_SET
,
3338 case BUILT_IN_SYNC_FETCH_AND_OR_1
:
3339 case BUILT_IN_SYNC_FETCH_AND_OR_2
:
3340 case BUILT_IN_SYNC_FETCH_AND_OR_4
:
3341 case BUILT_IN_SYNC_FETCH_AND_OR_8
:
3342 case BUILT_IN_SYNC_FETCH_AND_OR_16
:
3343 optimize_atomic_bit_test_and (&i
,
3344 IFN_ATOMIC_BIT_TEST_AND_SET
,
3348 case BUILT_IN_ATOMIC_FETCH_XOR_1
:
3349 case BUILT_IN_ATOMIC_FETCH_XOR_2
:
3350 case BUILT_IN_ATOMIC_FETCH_XOR_4
:
3351 case BUILT_IN_ATOMIC_FETCH_XOR_8
:
3352 case BUILT_IN_ATOMIC_FETCH_XOR_16
:
3353 optimize_atomic_bit_test_and
3354 (&i
, IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT
, true, false);
3356 case BUILT_IN_SYNC_FETCH_AND_XOR_1
:
3357 case BUILT_IN_SYNC_FETCH_AND_XOR_2
:
3358 case BUILT_IN_SYNC_FETCH_AND_XOR_4
:
3359 case BUILT_IN_SYNC_FETCH_AND_XOR_8
:
3360 case BUILT_IN_SYNC_FETCH_AND_XOR_16
:
3361 optimize_atomic_bit_test_and
3362 (&i
, IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT
, false, false);
3365 case BUILT_IN_ATOMIC_XOR_FETCH_1
:
3366 case BUILT_IN_ATOMIC_XOR_FETCH_2
:
3367 case BUILT_IN_ATOMIC_XOR_FETCH_4
:
3368 case BUILT_IN_ATOMIC_XOR_FETCH_8
:
3369 case BUILT_IN_ATOMIC_XOR_FETCH_16
:
3370 optimize_atomic_bit_test_and
3371 (&i
, IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT
, true, true);
3373 case BUILT_IN_SYNC_XOR_AND_FETCH_1
:
3374 case BUILT_IN_SYNC_XOR_AND_FETCH_2
:
3375 case BUILT_IN_SYNC_XOR_AND_FETCH_4
:
3376 case BUILT_IN_SYNC_XOR_AND_FETCH_8
:
3377 case BUILT_IN_SYNC_XOR_AND_FETCH_16
:
3378 optimize_atomic_bit_test_and
3379 (&i
, IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT
, false, true);
3382 case BUILT_IN_ATOMIC_FETCH_AND_1
:
3383 case BUILT_IN_ATOMIC_FETCH_AND_2
:
3384 case BUILT_IN_ATOMIC_FETCH_AND_4
:
3385 case BUILT_IN_ATOMIC_FETCH_AND_8
:
3386 case BUILT_IN_ATOMIC_FETCH_AND_16
:
3387 optimize_atomic_bit_test_and (&i
,
3388 IFN_ATOMIC_BIT_TEST_AND_RESET
,
3391 case BUILT_IN_SYNC_FETCH_AND_AND_1
:
3392 case BUILT_IN_SYNC_FETCH_AND_AND_2
:
3393 case BUILT_IN_SYNC_FETCH_AND_AND_4
:
3394 case BUILT_IN_SYNC_FETCH_AND_AND_8
:
3395 case BUILT_IN_SYNC_FETCH_AND_AND_16
:
3396 optimize_atomic_bit_test_and (&i
,
3397 IFN_ATOMIC_BIT_TEST_AND_RESET
,
3401 case BUILT_IN_MEMCPY
:
3402 if (gimple_call_builtin_p (stmt
, BUILT_IN_NORMAL
)
3403 && TREE_CODE (gimple_call_arg (stmt
, 0)) == ADDR_EXPR
3404 && TREE_CODE (gimple_call_arg (stmt
, 1)) == ADDR_EXPR
3405 && TREE_CODE (gimple_call_arg (stmt
, 2)) == INTEGER_CST
)
3407 tree dest
= TREE_OPERAND (gimple_call_arg (stmt
, 0), 0);
3408 tree src
= TREE_OPERAND (gimple_call_arg (stmt
, 1), 0);
3409 tree len
= gimple_call_arg (stmt
, 2);
3410 optimize_memcpy (&i
, dest
, src
, len
);
3414 case BUILT_IN_VA_START
:
3415 case BUILT_IN_VA_END
:
3416 case BUILT_IN_VA_COPY
:
3417 /* These shouldn't be folded before pass_stdarg. */
3418 result
= optimize_stdarg_builtin (stmt
);
3430 if (!update_call_from_tree (&i
, result
))
3431 gimplify_and_update_call_from_tree (&i
, result
);
3434 todoflags
|= TODO_update_address_taken
;
3436 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3438 fprintf (dump_file
, "Simplified\n ");
3439 print_gimple_stmt (dump_file
, stmt
, 0, dump_flags
);
3443 stmt
= gsi_stmt (i
);
3446 if (maybe_clean_or_replace_eh_stmt (old_stmt
, stmt
)
3447 && gimple_purge_dead_eh_edges (bb
))
3450 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3452 fprintf (dump_file
, "to\n ");
3453 print_gimple_stmt (dump_file
, stmt
, 0, dump_flags
);
3454 fprintf (dump_file
, "\n");
3457 /* Retry the same statement if it changed into another
3458 builtin, there might be new opportunities now. */
3459 if (gimple_code (stmt
) != GIMPLE_CALL
)
3464 callee
= gimple_call_fndecl (stmt
);
3466 || !fndecl_built_in_p (callee
, fcode
))
3471 /* Delete unreachable blocks. */
3473 todoflags
|= TODO_cleanup_cfg
;
3481 make_pass_fold_builtins (gcc::context
*ctxt
)
3483 return new pass_fold_builtins (ctxt
);
3486 /* A simple pass that emits some warnings post IPA. */
3490 const pass_data pass_data_post_ipa_warn
=
3492 GIMPLE_PASS
, /* type */
3493 "post_ipa_warn", /* name */
3494 OPTGROUP_NONE
, /* optinfo_flags */
3495 TV_NONE
, /* tv_id */
3496 ( PROP_cfg
| PROP_ssa
), /* properties_required */
3497 0, /* properties_provided */
3498 0, /* properties_destroyed */
3499 0, /* todo_flags_start */
3500 0, /* todo_flags_finish */
3503 class pass_post_ipa_warn
: public gimple_opt_pass
3506 pass_post_ipa_warn (gcc::context
*ctxt
)
3507 : gimple_opt_pass (pass_data_post_ipa_warn
, ctxt
)
3510 /* opt_pass methods: */
3511 opt_pass
* clone () { return new pass_post_ipa_warn (m_ctxt
); }
3512 virtual bool gate (function
*) { return warn_nonnull
!= 0; }
3513 virtual unsigned int execute (function
*);
3515 }; // class pass_fold_builtins
3518 pass_post_ipa_warn::execute (function
*fun
)
3522 FOR_EACH_BB_FN (bb
, fun
)
3524 gimple_stmt_iterator gsi
;
3525 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3527 gimple
*stmt
= gsi_stmt (gsi
);
3528 if (!is_gimple_call (stmt
) || gimple_no_warning_p (stmt
))
3534 = get_nonnull_args (gimple_call_fntype (stmt
));
3537 for (unsigned i
= 0; i
< gimple_call_num_args (stmt
); i
++)
3539 tree arg
= gimple_call_arg (stmt
, i
);
3540 if (TREE_CODE (TREE_TYPE (arg
)) != POINTER_TYPE
)
3542 if (!integer_zerop (arg
))
3544 if (!bitmap_empty_p (nonnullargs
)
3545 && !bitmap_bit_p (nonnullargs
, i
))
3548 location_t loc
= gimple_location (stmt
);
3549 auto_diagnostic_group d
;
3550 if (warning_at (loc
, OPT_Wnonnull
,
3551 "%Gargument %u null where non-null "
3552 "expected", stmt
, i
+ 1))
3554 tree fndecl
= gimple_call_fndecl (stmt
);
3555 if (fndecl
&& DECL_IS_BUILTIN (fndecl
))
3556 inform (loc
, "in a call to built-in function %qD",
3559 inform (DECL_SOURCE_LOCATION (fndecl
),
3560 "in a call to function %qD declared here",
3565 BITMAP_FREE (nonnullargs
);
3576 make_pass_post_ipa_warn (gcc::context
*ctxt
)
3578 return new pass_post_ipa_warn (ctxt
);