1 /* Conditional constant propagation pass for the GNU compiler.
2 Copyright (C) 2000-2017 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"
140 #include "builtins.h"
141 #include "tree-chkp.h"
143 #include "stor-layout.h"
144 #include "optabs-query.h"
145 #include "tree-ssa-ccp.h"
146 #include "tree-dfa.h"
147 #include "diagnostic-core.h"
149 /* Possible lattice values. */
158 struct ccp_prop_value_t
{
160 ccp_lattice_t lattice_val
;
162 /* Propagated value. */
165 /* Mask that applies to the propagated value during CCP. For X
166 with a CONSTANT lattice value X & ~mask == value & ~mask. The
167 zero bits in the mask cover constant values. The ones mean no
172 /* Array of propagated constant values. After propagation,
173 CONST_VAL[I].VALUE holds the constant value for SSA_NAME(I). If
174 the constant is held in an SSA name representing a memory store
175 (i.e., a VDEF), CONST_VAL[I].MEM_REF will contain the actual
176 memory reference used to store (i.e., the LHS of the assignment
178 static ccp_prop_value_t
*const_val
;
179 static unsigned n_const_val
;
181 static void canonicalize_value (ccp_prop_value_t
*);
182 static bool ccp_fold_stmt (gimple_stmt_iterator
*);
183 static void ccp_lattice_meet (ccp_prop_value_t
*, ccp_prop_value_t
*);
185 /* Dump constant propagation value VAL to file OUTF prefixed by PREFIX. */
188 dump_lattice_value (FILE *outf
, const char *prefix
, ccp_prop_value_t val
)
190 switch (val
.lattice_val
)
193 fprintf (outf
, "%sUNINITIALIZED", prefix
);
196 fprintf (outf
, "%sUNDEFINED", prefix
);
199 fprintf (outf
, "%sVARYING", prefix
);
202 if (TREE_CODE (val
.value
) != INTEGER_CST
205 fprintf (outf
, "%sCONSTANT ", prefix
);
206 print_generic_expr (outf
, val
.value
, dump_flags
);
210 widest_int cval
= wi::bit_and_not (wi::to_widest (val
.value
),
212 fprintf (outf
, "%sCONSTANT ", prefix
);
213 print_hex (cval
, outf
);
214 fprintf (outf
, " (");
215 print_hex (val
.mask
, outf
);
225 /* Print lattice value VAL to stderr. */
227 void debug_lattice_value (ccp_prop_value_t val
);
230 debug_lattice_value (ccp_prop_value_t val
)
232 dump_lattice_value (stderr
, "", val
);
233 fprintf (stderr
, "\n");
236 /* Extend NONZERO_BITS to a full mask, based on sgn. */
239 extend_mask (const wide_int
&nonzero_bits
, signop sgn
)
241 return widest_int::from (nonzero_bits
, sgn
);
244 /* Compute a default value for variable VAR and store it in the
245 CONST_VAL array. The following rules are used to get default
248 1- Global and static variables that are declared constant are
251 2- Any other value is considered UNDEFINED. This is useful when
252 considering PHI nodes. PHI arguments that are undefined do not
253 change the constant value of the PHI node, which allows for more
254 constants to be propagated.
256 3- Variables defined by statements other than assignments and PHI
257 nodes are considered VARYING.
259 4- Initial values of variables that are not GIMPLE registers are
260 considered VARYING. */
262 static ccp_prop_value_t
263 get_default_value (tree var
)
265 ccp_prop_value_t val
= { UNINITIALIZED
, NULL_TREE
, 0 };
268 stmt
= SSA_NAME_DEF_STMT (var
);
270 if (gimple_nop_p (stmt
))
272 /* Variables defined by an empty statement are those used
273 before being initialized. If VAR is a local variable, we
274 can assume initially that it is UNDEFINED, otherwise we must
275 consider it VARYING. */
276 if (!virtual_operand_p (var
)
277 && SSA_NAME_VAR (var
)
278 && TREE_CODE (SSA_NAME_VAR (var
)) == VAR_DECL
)
279 val
.lattice_val
= UNDEFINED
;
282 val
.lattice_val
= VARYING
;
284 if (flag_tree_bit_ccp
)
286 wide_int nonzero_bits
= get_nonzero_bits (var
);
287 if (nonzero_bits
!= -1)
289 val
.lattice_val
= CONSTANT
;
290 val
.value
= build_zero_cst (TREE_TYPE (var
));
291 val
.mask
= extend_mask (nonzero_bits
, TYPE_SIGN (TREE_TYPE (var
)));
296 else if (is_gimple_assign (stmt
))
299 if (gimple_assign_single_p (stmt
)
300 && DECL_P (gimple_assign_rhs1 (stmt
))
301 && (cst
= get_symbol_constant_value (gimple_assign_rhs1 (stmt
))))
303 val
.lattice_val
= CONSTANT
;
308 /* Any other variable defined by an assignment is considered
310 val
.lattice_val
= UNDEFINED
;
313 else if ((is_gimple_call (stmt
)
314 && gimple_call_lhs (stmt
) != NULL_TREE
)
315 || gimple_code (stmt
) == GIMPLE_PHI
)
317 /* A variable defined by a call or a PHI node is considered
319 val
.lattice_val
= UNDEFINED
;
323 /* Otherwise, VAR will never take on a constant value. */
324 val
.lattice_val
= VARYING
;
332 /* Get the constant value associated with variable VAR. */
334 static inline ccp_prop_value_t
*
337 ccp_prop_value_t
*val
;
339 if (const_val
== NULL
340 || SSA_NAME_VERSION (var
) >= n_const_val
)
343 val
= &const_val
[SSA_NAME_VERSION (var
)];
344 if (val
->lattice_val
== UNINITIALIZED
)
345 *val
= get_default_value (var
);
347 canonicalize_value (val
);
352 /* Return the constant tree value associated with VAR. */
355 get_constant_value (tree var
)
357 ccp_prop_value_t
*val
;
358 if (TREE_CODE (var
) != SSA_NAME
)
360 if (is_gimple_min_invariant (var
))
364 val
= get_value (var
);
366 && val
->lattice_val
== CONSTANT
367 && (TREE_CODE (val
->value
) != INTEGER_CST
373 /* Sets the value associated with VAR to VARYING. */
376 set_value_varying (tree var
)
378 ccp_prop_value_t
*val
= &const_val
[SSA_NAME_VERSION (var
)];
380 val
->lattice_val
= VARYING
;
381 val
->value
= NULL_TREE
;
385 /* For integer constants, make sure to drop TREE_OVERFLOW. */
388 canonicalize_value (ccp_prop_value_t
*val
)
390 if (val
->lattice_val
!= CONSTANT
)
393 if (TREE_OVERFLOW_P (val
->value
))
394 val
->value
= drop_tree_overflow (val
->value
);
397 /* Return whether the lattice transition is valid. */
400 valid_lattice_transition (ccp_prop_value_t old_val
, ccp_prop_value_t new_val
)
402 /* Lattice transitions must always be monotonically increasing in
404 if (old_val
.lattice_val
< new_val
.lattice_val
)
407 if (old_val
.lattice_val
!= new_val
.lattice_val
)
410 if (!old_val
.value
&& !new_val
.value
)
413 /* Now both lattice values are CONSTANT. */
415 /* Allow arbitrary copy changes as we might look through PHI <a_1, ...>
416 when only a single copy edge is executable. */
417 if (TREE_CODE (old_val
.value
) == SSA_NAME
418 && TREE_CODE (new_val
.value
) == SSA_NAME
)
421 /* Allow transitioning from a constant to a copy. */
422 if (is_gimple_min_invariant (old_val
.value
)
423 && TREE_CODE (new_val
.value
) == SSA_NAME
)
426 /* Allow transitioning from PHI <&x, not executable> == &x
427 to PHI <&x, &y> == common alignment. */
428 if (TREE_CODE (old_val
.value
) != INTEGER_CST
429 && TREE_CODE (new_val
.value
) == INTEGER_CST
)
432 /* Bit-lattices have to agree in the still valid bits. */
433 if (TREE_CODE (old_val
.value
) == INTEGER_CST
434 && TREE_CODE (new_val
.value
) == INTEGER_CST
)
435 return (wi::bit_and_not (wi::to_widest (old_val
.value
), new_val
.mask
)
436 == wi::bit_and_not (wi::to_widest (new_val
.value
), new_val
.mask
));
438 /* Otherwise constant values have to agree. */
439 if (operand_equal_p (old_val
.value
, new_val
.value
, 0))
442 /* At least the kinds and types should agree now. */
443 if (TREE_CODE (old_val
.value
) != TREE_CODE (new_val
.value
)
444 || !types_compatible_p (TREE_TYPE (old_val
.value
),
445 TREE_TYPE (new_val
.value
)))
448 /* For floats and !HONOR_NANS allow transitions from (partial) NaN
450 tree type
= TREE_TYPE (new_val
.value
);
451 if (SCALAR_FLOAT_TYPE_P (type
)
452 && !HONOR_NANS (type
))
454 if (REAL_VALUE_ISNAN (TREE_REAL_CST (old_val
.value
)))
457 else if (VECTOR_FLOAT_TYPE_P (type
)
458 && !HONOR_NANS (type
))
460 for (unsigned i
= 0; i
< VECTOR_CST_NELTS (old_val
.value
); ++i
)
461 if (!REAL_VALUE_ISNAN
462 (TREE_REAL_CST (VECTOR_CST_ELT (old_val
.value
, i
)))
463 && !operand_equal_p (VECTOR_CST_ELT (old_val
.value
, i
),
464 VECTOR_CST_ELT (new_val
.value
, i
), 0))
468 else if (COMPLEX_FLOAT_TYPE_P (type
)
469 && !HONOR_NANS (type
))
471 if (!REAL_VALUE_ISNAN (TREE_REAL_CST (TREE_REALPART (old_val
.value
)))
472 && !operand_equal_p (TREE_REALPART (old_val
.value
),
473 TREE_REALPART (new_val
.value
), 0))
475 if (!REAL_VALUE_ISNAN (TREE_REAL_CST (TREE_IMAGPART (old_val
.value
)))
476 && !operand_equal_p (TREE_IMAGPART (old_val
.value
),
477 TREE_IMAGPART (new_val
.value
), 0))
484 /* Set the value for variable VAR to NEW_VAL. Return true if the new
485 value is different from VAR's previous value. */
488 set_lattice_value (tree var
, ccp_prop_value_t
*new_val
)
490 /* We can deal with old UNINITIALIZED values just fine here. */
491 ccp_prop_value_t
*old_val
= &const_val
[SSA_NAME_VERSION (var
)];
493 canonicalize_value (new_val
);
495 /* We have to be careful to not go up the bitwise lattice
496 represented by the mask. Instead of dropping to VARYING
497 use the meet operator to retain a conservative value.
498 Missed optimizations like PR65851 makes this necessary.
499 It also ensures we converge to a stable lattice solution. */
500 if (new_val
->lattice_val
== CONSTANT
501 && old_val
->lattice_val
== CONSTANT
502 && TREE_CODE (new_val
->value
) != SSA_NAME
)
503 ccp_lattice_meet (new_val
, old_val
);
505 gcc_checking_assert (valid_lattice_transition (*old_val
, *new_val
));
507 /* If *OLD_VAL and NEW_VAL are the same, return false to inform the
508 caller that this was a non-transition. */
509 if (old_val
->lattice_val
!= new_val
->lattice_val
510 || (new_val
->lattice_val
== CONSTANT
511 && (TREE_CODE (new_val
->value
) != TREE_CODE (old_val
->value
)
512 || (TREE_CODE (new_val
->value
) == INTEGER_CST
513 && (new_val
->mask
!= old_val
->mask
514 || (wi::bit_and_not (wi::to_widest (old_val
->value
),
516 != wi::bit_and_not (wi::to_widest (new_val
->value
),
518 || (TREE_CODE (new_val
->value
) != INTEGER_CST
519 && !operand_equal_p (new_val
->value
, old_val
->value
, 0)))))
521 /* ??? We would like to delay creation of INTEGER_CSTs from
522 partially constants here. */
524 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
526 dump_lattice_value (dump_file
, "Lattice value changed to ", *new_val
);
527 fprintf (dump_file
, ". Adding SSA edges to worklist.\n");
532 gcc_assert (new_val
->lattice_val
!= UNINITIALIZED
);
539 static ccp_prop_value_t
get_value_for_expr (tree
, bool);
540 static ccp_prop_value_t
bit_value_binop (enum tree_code
, tree
, tree
, tree
);
541 void bit_value_binop (enum tree_code
, signop
, int, widest_int
*, widest_int
*,
542 signop
, int, const widest_int
&, const widest_int
&,
543 signop
, int, const widest_int
&, const widest_int
&);
545 /* Return a widest_int that can be used for bitwise simplifications
549 value_to_wide_int (ccp_prop_value_t val
)
552 && TREE_CODE (val
.value
) == INTEGER_CST
)
553 return wi::to_widest (val
.value
);
558 /* Return the value for the address expression EXPR based on alignment
561 static ccp_prop_value_t
562 get_value_from_alignment (tree expr
)
564 tree type
= TREE_TYPE (expr
);
565 ccp_prop_value_t val
;
566 unsigned HOST_WIDE_INT bitpos
;
569 gcc_assert (TREE_CODE (expr
) == ADDR_EXPR
);
571 get_pointer_alignment_1 (expr
, &align
, &bitpos
);
572 val
.mask
= (POINTER_TYPE_P (type
) || TYPE_UNSIGNED (type
)
573 ? wi::mask
<widest_int
> (TYPE_PRECISION (type
), false)
574 : -1).and_not (align
/ BITS_PER_UNIT
- 1);
576 = wi::sext (val
.mask
, TYPE_PRECISION (type
)) == -1 ? VARYING
: CONSTANT
;
577 if (val
.lattice_val
== CONSTANT
)
578 val
.value
= build_int_cstu (type
, bitpos
/ BITS_PER_UNIT
);
580 val
.value
= NULL_TREE
;
585 /* Return the value for the tree operand EXPR. If FOR_BITS_P is true
586 return constant bits extracted from alignment information for
587 invariant addresses. */
589 static ccp_prop_value_t
590 get_value_for_expr (tree expr
, bool for_bits_p
)
592 ccp_prop_value_t val
;
594 if (TREE_CODE (expr
) == SSA_NAME
)
596 ccp_prop_value_t
*val_
= get_value (expr
);
601 val
.lattice_val
= VARYING
;
602 val
.value
= NULL_TREE
;
606 && val
.lattice_val
== CONSTANT
607 && TREE_CODE (val
.value
) == ADDR_EXPR
)
608 val
= get_value_from_alignment (val
.value
);
609 /* Fall back to a copy value. */
611 && val
.lattice_val
== VARYING
612 && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (expr
))
614 val
.lattice_val
= CONSTANT
;
619 else if (is_gimple_min_invariant (expr
)
620 && (!for_bits_p
|| TREE_CODE (expr
) != ADDR_EXPR
))
622 val
.lattice_val
= CONSTANT
;
625 canonicalize_value (&val
);
627 else if (TREE_CODE (expr
) == ADDR_EXPR
)
628 val
= get_value_from_alignment (expr
);
631 val
.lattice_val
= VARYING
;
633 val
.value
= NULL_TREE
;
636 if (val
.lattice_val
== VARYING
637 && TYPE_UNSIGNED (TREE_TYPE (expr
)))
638 val
.mask
= wi::zext (val
.mask
, TYPE_PRECISION (TREE_TYPE (expr
)));
643 /* Return the likely CCP lattice value for STMT.
645 If STMT has no operands, then return CONSTANT.
647 Else if undefinedness of operands of STMT cause its value to be
648 undefined, then return UNDEFINED.
650 Else if any operands of STMT are constants, then return CONSTANT.
652 Else return VARYING. */
655 likely_value (gimple
*stmt
)
657 bool has_constant_operand
, has_undefined_operand
, all_undefined_operands
;
658 bool has_nsa_operand
;
663 enum gimple_code code
= gimple_code (stmt
);
665 /* This function appears to be called only for assignments, calls,
666 conditionals, and switches, due to the logic in visit_stmt. */
667 gcc_assert (code
== GIMPLE_ASSIGN
668 || code
== GIMPLE_CALL
669 || code
== GIMPLE_COND
670 || code
== GIMPLE_SWITCH
);
672 /* If the statement has volatile operands, it won't fold to a
674 if (gimple_has_volatile_ops (stmt
))
677 /* Arrive here for more complex cases. */
678 has_constant_operand
= false;
679 has_undefined_operand
= false;
680 all_undefined_operands
= true;
681 has_nsa_operand
= false;
682 FOR_EACH_SSA_TREE_OPERAND (use
, stmt
, iter
, SSA_OP_USE
)
684 ccp_prop_value_t
*val
= get_value (use
);
686 if (val
&& val
->lattice_val
== UNDEFINED
)
687 has_undefined_operand
= true;
689 all_undefined_operands
= false;
691 if (val
&& val
->lattice_val
== CONSTANT
)
692 has_constant_operand
= true;
694 if (SSA_NAME_IS_DEFAULT_DEF (use
)
695 || !prop_simulate_again_p (SSA_NAME_DEF_STMT (use
)))
696 has_nsa_operand
= true;
699 /* There may be constants in regular rhs operands. For calls we
700 have to ignore lhs, fndecl and static chain, otherwise only
702 for (i
= (is_gimple_call (stmt
) ? 2 : 0) + gimple_has_lhs (stmt
);
703 i
< gimple_num_ops (stmt
); ++i
)
705 tree op
= gimple_op (stmt
, i
);
706 if (!op
|| TREE_CODE (op
) == SSA_NAME
)
708 if (is_gimple_min_invariant (op
))
709 has_constant_operand
= true;
712 if (has_constant_operand
)
713 all_undefined_operands
= false;
715 if (has_undefined_operand
716 && code
== GIMPLE_CALL
717 && gimple_call_internal_p (stmt
))
718 switch (gimple_call_internal_fn (stmt
))
720 /* These 3 builtins use the first argument just as a magic
721 way how to find out a decl uid. */
722 case IFN_GOMP_SIMD_LANE
:
723 case IFN_GOMP_SIMD_VF
:
724 case IFN_GOMP_SIMD_LAST_LANE
:
725 has_undefined_operand
= false;
731 /* If the operation combines operands like COMPLEX_EXPR make sure to
732 not mark the result UNDEFINED if only one part of the result is
734 if (has_undefined_operand
&& all_undefined_operands
)
736 else if (code
== GIMPLE_ASSIGN
&& has_undefined_operand
)
738 switch (gimple_assign_rhs_code (stmt
))
740 /* Unary operators are handled with all_undefined_operands. */
743 case POINTER_PLUS_EXPR
:
745 /* Not MIN_EXPR, MAX_EXPR. One VARYING operand may be selected.
746 Not bitwise operators, one VARYING operand may specify the
748 Not logical operators for the same reason, apart from XOR.
749 Not COMPLEX_EXPR as one VARYING operand makes the result partly
750 not UNDEFINED. Not *DIV_EXPR, comparisons and shifts because
751 the undefined operand may be promoted. */
755 /* If any part of an address is UNDEFINED, like the index
756 of an ARRAY_EXPR, then treat the result as UNDEFINED. */
763 /* If there was an UNDEFINED operand but the result may be not UNDEFINED
764 fall back to CONSTANT. During iteration UNDEFINED may still drop
766 if (has_undefined_operand
)
769 /* We do not consider virtual operands here -- load from read-only
770 memory may have only VARYING virtual operands, but still be
771 constant. Also we can combine the stmt with definitions from
772 operands whose definitions are not simulated again. */
773 if (has_constant_operand
775 || gimple_references_memory_p (stmt
))
781 /* Returns true if STMT cannot be constant. */
784 surely_varying_stmt_p (gimple
*stmt
)
786 /* If the statement has operands that we cannot handle, it cannot be
788 if (gimple_has_volatile_ops (stmt
))
791 /* If it is a call and does not return a value or is not a
792 builtin and not an indirect call or a call to function with
793 assume_aligned/alloc_align attribute, it is varying. */
794 if (is_gimple_call (stmt
))
796 tree fndecl
, fntype
= gimple_call_fntype (stmt
);
797 if (!gimple_call_lhs (stmt
)
798 || ((fndecl
= gimple_call_fndecl (stmt
)) != NULL_TREE
799 && !DECL_BUILT_IN (fndecl
)
800 && !lookup_attribute ("assume_aligned",
801 TYPE_ATTRIBUTES (fntype
))
802 && !lookup_attribute ("alloc_align",
803 TYPE_ATTRIBUTES (fntype
))))
807 /* Any other store operation is not interesting. */
808 else if (gimple_vdef (stmt
))
811 /* Anything other than assignments and conditional jumps are not
812 interesting for CCP. */
813 if (gimple_code (stmt
) != GIMPLE_ASSIGN
814 && gimple_code (stmt
) != GIMPLE_COND
815 && gimple_code (stmt
) != GIMPLE_SWITCH
816 && gimple_code (stmt
) != GIMPLE_CALL
)
822 /* Initialize local data structures for CCP. */
825 ccp_initialize (void)
829 n_const_val
= num_ssa_names
;
830 const_val
= XCNEWVEC (ccp_prop_value_t
, n_const_val
);
832 /* Initialize simulation flags for PHI nodes and statements. */
833 FOR_EACH_BB_FN (bb
, cfun
)
835 gimple_stmt_iterator i
;
837 for (i
= gsi_start_bb (bb
); !gsi_end_p (i
); gsi_next (&i
))
839 gimple
*stmt
= gsi_stmt (i
);
842 /* If the statement is a control insn, then we do not
843 want to avoid simulating the statement once. Failure
844 to do so means that those edges will never get added. */
845 if (stmt_ends_bb_p (stmt
))
848 is_varying
= surely_varying_stmt_p (stmt
);
855 /* If the statement will not produce a constant, mark
856 all its outputs VARYING. */
857 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, iter
, SSA_OP_ALL_DEFS
)
858 set_value_varying (def
);
860 prop_set_simulate_again (stmt
, !is_varying
);
864 /* Now process PHI nodes. We never clear the simulate_again flag on
865 phi nodes, since we do not know which edges are executable yet,
866 except for phi nodes for virtual operands when we do not do store ccp. */
867 FOR_EACH_BB_FN (bb
, cfun
)
871 for (i
= gsi_start_phis (bb
); !gsi_end_p (i
); gsi_next (&i
))
873 gphi
*phi
= i
.phi ();
875 if (virtual_operand_p (gimple_phi_result (phi
)))
876 prop_set_simulate_again (phi
, false);
878 prop_set_simulate_again (phi
, true);
883 /* Debug count support. Reset the values of ssa names
884 VARYING when the total number ssa names analyzed is
885 beyond the debug count specified. */
891 for (i
= 0; i
< num_ssa_names
; i
++)
895 const_val
[i
].lattice_val
= VARYING
;
896 const_val
[i
].mask
= -1;
897 const_val
[i
].value
= NULL_TREE
;
903 /* Do final substitution of propagated values, cleanup the flowgraph and
904 free allocated storage. If NONZERO_P, record nonzero bits.
906 Return TRUE when something was optimized. */
909 ccp_finalize (bool nonzero_p
)
911 bool something_changed
;
917 /* Derive alignment and misalignment information from partially
918 constant pointers in the lattice or nonzero bits from partially
919 constant integers. */
920 FOR_EACH_SSA_NAME (i
, name
, cfun
)
922 ccp_prop_value_t
*val
;
923 unsigned int tem
, align
;
925 if (!POINTER_TYPE_P (TREE_TYPE (name
))
926 && (!INTEGRAL_TYPE_P (TREE_TYPE (name
))
927 /* Don't record nonzero bits before IPA to avoid
928 using too much memory. */
932 val
= get_value (name
);
933 if (val
->lattice_val
!= CONSTANT
934 || TREE_CODE (val
->value
) != INTEGER_CST
938 if (POINTER_TYPE_P (TREE_TYPE (name
)))
940 /* Trailing mask bits specify the alignment, trailing value
941 bits the misalignment. */
942 tem
= val
->mask
.to_uhwi ();
943 align
= least_bit_hwi (tem
);
945 set_ptr_info_alignment (get_ptr_info (name
), align
,
946 (TREE_INT_CST_LOW (val
->value
)
951 unsigned int precision
= TYPE_PRECISION (TREE_TYPE (val
->value
));
952 wide_int nonzero_bits
= wide_int::from (val
->mask
, precision
,
953 UNSIGNED
) | val
->value
;
954 nonzero_bits
&= get_nonzero_bits (name
);
955 set_nonzero_bits (name
, nonzero_bits
);
959 /* Perform substitutions based on the known constant values. */
960 something_changed
= substitute_and_fold (get_constant_value
, ccp_fold_stmt
);
964 return something_changed
;;
968 /* Compute the meet operator between *VAL1 and *VAL2. Store the result
971 any M UNDEFINED = any
972 any M VARYING = VARYING
973 Ci M Cj = Ci if (i == j)
974 Ci M Cj = VARYING if (i != j)
978 ccp_lattice_meet (ccp_prop_value_t
*val1
, ccp_prop_value_t
*val2
)
980 if (val1
->lattice_val
== UNDEFINED
981 /* For UNDEFINED M SSA we can't always SSA because its definition
982 may not dominate the PHI node. Doing optimistic copy propagation
983 also causes a lot of gcc.dg/uninit-pred*.c FAILs. */
984 && (val2
->lattice_val
!= CONSTANT
985 || TREE_CODE (val2
->value
) != SSA_NAME
))
987 /* UNDEFINED M any = any */
990 else if (val2
->lattice_val
== UNDEFINED
992 && (val1
->lattice_val
!= CONSTANT
993 || TREE_CODE (val1
->value
) != SSA_NAME
))
995 /* any M UNDEFINED = any
996 Nothing to do. VAL1 already contains the value we want. */
999 else if (val1
->lattice_val
== VARYING
1000 || val2
->lattice_val
== VARYING
)
1002 /* any M VARYING = VARYING. */
1003 val1
->lattice_val
= VARYING
;
1005 val1
->value
= NULL_TREE
;
1007 else if (val1
->lattice_val
== CONSTANT
1008 && val2
->lattice_val
== CONSTANT
1009 && TREE_CODE (val1
->value
) == INTEGER_CST
1010 && TREE_CODE (val2
->value
) == INTEGER_CST
)
1012 /* Ci M Cj = Ci if (i == j)
1013 Ci M Cj = VARYING if (i != j)
1015 For INTEGER_CSTs mask unequal bits. If no equal bits remain,
1017 val1
->mask
= (val1
->mask
| val2
->mask
1018 | (wi::to_widest (val1
->value
)
1019 ^ wi::to_widest (val2
->value
)));
1020 if (wi::sext (val1
->mask
, TYPE_PRECISION (TREE_TYPE (val1
->value
))) == -1)
1022 val1
->lattice_val
= VARYING
;
1023 val1
->value
= NULL_TREE
;
1026 else if (val1
->lattice_val
== CONSTANT
1027 && val2
->lattice_val
== CONSTANT
1028 && operand_equal_p (val1
->value
, val2
->value
, 0))
1030 /* Ci M Cj = Ci if (i == j)
1031 Ci M Cj = VARYING if (i != j)
1033 VAL1 already contains the value we want for equivalent values. */
1035 else if (val1
->lattice_val
== CONSTANT
1036 && val2
->lattice_val
== CONSTANT
1037 && (TREE_CODE (val1
->value
) == ADDR_EXPR
1038 || TREE_CODE (val2
->value
) == ADDR_EXPR
))
1040 /* When not equal addresses are involved try meeting for
1042 ccp_prop_value_t tem
= *val2
;
1043 if (TREE_CODE (val1
->value
) == ADDR_EXPR
)
1044 *val1
= get_value_for_expr (val1
->value
, true);
1045 if (TREE_CODE (val2
->value
) == ADDR_EXPR
)
1046 tem
= get_value_for_expr (val2
->value
, true);
1047 ccp_lattice_meet (val1
, &tem
);
1051 /* Any other combination is VARYING. */
1052 val1
->lattice_val
= VARYING
;
1054 val1
->value
= NULL_TREE
;
1059 /* Loop through the PHI_NODE's parameters for BLOCK and compare their
1060 lattice values to determine PHI_NODE's lattice value. The value of a
1061 PHI node is determined calling ccp_lattice_meet with all the arguments
1062 of the PHI node that are incoming via executable edges. */
1064 static enum ssa_prop_result
1065 ccp_visit_phi_node (gphi
*phi
)
1068 ccp_prop_value_t new_val
;
1070 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1072 fprintf (dump_file
, "\nVisiting PHI node: ");
1073 print_gimple_stmt (dump_file
, phi
, 0, dump_flags
);
1076 new_val
.lattice_val
= UNDEFINED
;
1077 new_val
.value
= NULL_TREE
;
1081 bool non_exec_edge
= false;
1082 for (i
= 0; i
< gimple_phi_num_args (phi
); i
++)
1084 /* Compute the meet operator over all the PHI arguments flowing
1085 through executable edges. */
1086 edge e
= gimple_phi_arg_edge (phi
, i
);
1088 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1091 "\n Argument #%d (%d -> %d %sexecutable)\n",
1092 i
, e
->src
->index
, e
->dest
->index
,
1093 (e
->flags
& EDGE_EXECUTABLE
) ? "" : "not ");
1096 /* If the incoming edge is executable, Compute the meet operator for
1097 the existing value of the PHI node and the current PHI argument. */
1098 if (e
->flags
& EDGE_EXECUTABLE
)
1100 tree arg
= gimple_phi_arg (phi
, i
)->def
;
1101 ccp_prop_value_t arg_val
= get_value_for_expr (arg
, false);
1109 ccp_lattice_meet (&new_val
, &arg_val
);
1111 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1113 fprintf (dump_file
, "\t");
1114 print_generic_expr (dump_file
, arg
, dump_flags
);
1115 dump_lattice_value (dump_file
, "\tValue: ", arg_val
);
1116 fprintf (dump_file
, "\n");
1119 if (new_val
.lattice_val
== VARYING
)
1123 non_exec_edge
= true;
1126 /* In case there were non-executable edges and the value is a copy
1127 make sure its definition dominates the PHI node. */
1129 && new_val
.lattice_val
== CONSTANT
1130 && TREE_CODE (new_val
.value
) == SSA_NAME
1131 && ! SSA_NAME_IS_DEFAULT_DEF (new_val
.value
)
1132 && ! dominated_by_p (CDI_DOMINATORS
, gimple_bb (phi
),
1133 gimple_bb (SSA_NAME_DEF_STMT (new_val
.value
))))
1135 new_val
.lattice_val
= VARYING
;
1136 new_val
.value
= NULL_TREE
;
1140 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1142 dump_lattice_value (dump_file
, "\n PHI node value: ", new_val
);
1143 fprintf (dump_file
, "\n\n");
1146 /* Make the transition to the new value. */
1147 if (set_lattice_value (gimple_phi_result (phi
), &new_val
))
1149 if (new_val
.lattice_val
== VARYING
)
1150 return SSA_PROP_VARYING
;
1152 return SSA_PROP_INTERESTING
;
1155 return SSA_PROP_NOT_INTERESTING
;
1158 /* Return the constant value for OP or OP otherwise. */
1161 valueize_op (tree op
)
1163 if (TREE_CODE (op
) == SSA_NAME
)
1165 tree tem
= get_constant_value (op
);
1172 /* Return the constant value for OP, but signal to not follow SSA
1173 edges if the definition may be simulated again. */
1176 valueize_op_1 (tree op
)
1178 if (TREE_CODE (op
) == SSA_NAME
)
1180 /* If the definition may be simulated again we cannot follow
1181 this SSA edge as the SSA propagator does not necessarily
1182 re-visit the use. */
1183 gimple
*def_stmt
= SSA_NAME_DEF_STMT (op
);
1184 if (!gimple_nop_p (def_stmt
)
1185 && prop_simulate_again_p (def_stmt
))
1187 tree tem
= get_constant_value (op
);
1194 /* CCP specific front-end to the non-destructive constant folding
1197 Attempt to simplify the RHS of STMT knowing that one or more
1198 operands are constants.
1200 If simplification is possible, return the simplified RHS,
1201 otherwise return the original RHS or NULL_TREE. */
1204 ccp_fold (gimple
*stmt
)
1206 location_t loc
= gimple_location (stmt
);
1207 switch (gimple_code (stmt
))
1211 /* Handle comparison operators that can appear in GIMPLE form. */
1212 tree op0
= valueize_op (gimple_cond_lhs (stmt
));
1213 tree op1
= valueize_op (gimple_cond_rhs (stmt
));
1214 enum tree_code code
= gimple_cond_code (stmt
);
1215 return fold_binary_loc (loc
, code
, boolean_type_node
, op0
, op1
);
1220 /* Return the constant switch index. */
1221 return valueize_op (gimple_switch_index (as_a
<gswitch
*> (stmt
)));
1226 return gimple_fold_stmt_to_constant_1 (stmt
,
1227 valueize_op
, valueize_op_1
);
1234 /* Apply the operation CODE in type TYPE to the value, mask pair
1235 RVAL and RMASK representing a value of type RTYPE and set
1236 the value, mask pair *VAL and *MASK to the result. */
1239 bit_value_unop (enum tree_code code
, signop type_sgn
, int type_precision
,
1240 widest_int
*val
, widest_int
*mask
,
1241 signop rtype_sgn
, int rtype_precision
,
1242 const widest_int
&rval
, const widest_int
&rmask
)
1253 widest_int temv
, temm
;
1254 /* Return ~rval + 1. */
1255 bit_value_unop (BIT_NOT_EXPR
, type_sgn
, type_precision
, &temv
, &temm
,
1256 type_sgn
, type_precision
, rval
, rmask
);
1257 bit_value_binop (PLUS_EXPR
, type_sgn
, type_precision
, val
, mask
,
1258 type_sgn
, type_precision
, temv
, temm
,
1259 type_sgn
, type_precision
, 1, 0);
1265 /* First extend mask and value according to the original type. */
1266 *mask
= wi::ext (rmask
, rtype_precision
, rtype_sgn
);
1267 *val
= wi::ext (rval
, rtype_precision
, rtype_sgn
);
1269 /* Then extend mask and value according to the target type. */
1270 *mask
= wi::ext (*mask
, type_precision
, type_sgn
);
1271 *val
= wi::ext (*val
, type_precision
, type_sgn
);
1281 /* Apply the operation CODE in type TYPE to the value, mask pairs
1282 R1VAL, R1MASK and R2VAL, R2MASK representing a values of type R1TYPE
1283 and R2TYPE and set the value, mask pair *VAL and *MASK to the result. */
1286 bit_value_binop (enum tree_code code
, signop sgn
, int width
,
1287 widest_int
*val
, widest_int
*mask
,
1288 signop r1type_sgn
, int r1type_precision
,
1289 const widest_int
&r1val
, const widest_int
&r1mask
,
1290 signop r2type_sgn
, int r2type_precision
,
1291 const widest_int
&r2val
, const widest_int
&r2mask
)
1293 bool swap_p
= false;
1295 /* Assume we'll get a constant result. Use an initial non varying
1296 value, we fall back to varying in the end if necessary. */
1302 /* The mask is constant where there is a known not
1303 set bit, (m1 | m2) & ((v1 | m1) & (v2 | m2)) */
1304 *mask
= (r1mask
| r2mask
) & (r1val
| r1mask
) & (r2val
| r2mask
);
1305 *val
= r1val
& r2val
;
1309 /* The mask is constant where there is a known
1310 set bit, (m1 | m2) & ~((v1 & ~m1) | (v2 & ~m2)). */
1311 *mask
= (r1mask
| r2mask
)
1312 .and_not (r1val
.and_not (r1mask
) | r2val
.and_not (r2mask
));
1313 *val
= r1val
| r2val
;
1318 *mask
= r1mask
| r2mask
;
1319 *val
= r1val
^ r2val
;
1326 widest_int shift
= r2val
;
1334 if (wi::neg_p (shift
))
1337 if (code
== RROTATE_EXPR
)
1338 code
= LROTATE_EXPR
;
1340 code
= RROTATE_EXPR
;
1342 if (code
== RROTATE_EXPR
)
1344 *mask
= wi::rrotate (r1mask
, shift
, width
);
1345 *val
= wi::rrotate (r1val
, shift
, width
);
1349 *mask
= wi::lrotate (r1mask
, shift
, width
);
1350 *val
= wi::lrotate (r1val
, shift
, width
);
1358 /* ??? We can handle partially known shift counts if we know
1359 its sign. That way we can tell that (x << (y | 8)) & 255
1363 widest_int shift
= r2val
;
1371 if (wi::neg_p (shift
))
1374 if (code
== RSHIFT_EXPR
)
1379 if (code
== RSHIFT_EXPR
)
1381 *mask
= wi::rshift (wi::ext (r1mask
, width
, sgn
), shift
, sgn
);
1382 *val
= wi::rshift (wi::ext (r1val
, width
, sgn
), shift
, sgn
);
1386 *mask
= wi::ext (r1mask
<< shift
, width
, sgn
);
1387 *val
= wi::ext (r1val
<< shift
, width
, sgn
);
1394 case POINTER_PLUS_EXPR
:
1396 /* Do the addition with unknown bits set to zero, to give carry-ins of
1397 zero wherever possible. */
1398 widest_int lo
= r1val
.and_not (r1mask
) + r2val
.and_not (r2mask
);
1399 lo
= wi::ext (lo
, width
, sgn
);
1400 /* Do the addition with unknown bits set to one, to give carry-ins of
1401 one wherever possible. */
1402 widest_int hi
= (r1val
| r1mask
) + (r2val
| r2mask
);
1403 hi
= wi::ext (hi
, width
, sgn
);
1404 /* Each bit in the result is known if (a) the corresponding bits in
1405 both inputs are known, and (b) the carry-in to that bit position
1406 is known. We can check condition (b) by seeing if we got the same
1407 result with minimised carries as with maximised carries. */
1408 *mask
= r1mask
| r2mask
| (lo
^ hi
);
1409 *mask
= wi::ext (*mask
, width
, sgn
);
1410 /* It shouldn't matter whether we choose lo or hi here. */
1417 widest_int temv
, temm
;
1418 bit_value_unop (NEGATE_EXPR
, r2type_sgn
, r2type_precision
, &temv
, &temm
,
1419 r2type_sgn
, r2type_precision
, r2val
, r2mask
);
1420 bit_value_binop (PLUS_EXPR
, sgn
, width
, val
, mask
,
1421 r1type_sgn
, r1type_precision
, r1val
, r1mask
,
1422 r2type_sgn
, r2type_precision
, temv
, temm
);
1428 /* Just track trailing zeros in both operands and transfer
1429 them to the other. */
1430 int r1tz
= wi::ctz (r1val
| r1mask
);
1431 int r2tz
= wi::ctz (r2val
| r2mask
);
1432 if (r1tz
+ r2tz
>= width
)
1437 else if (r1tz
+ r2tz
> 0)
1439 *mask
= wi::ext (wi::mask
<widest_int
> (r1tz
+ r2tz
, true),
1449 widest_int m
= r1mask
| r2mask
;
1450 if (r1val
.and_not (m
) != r2val
.and_not (m
))
1453 *val
= ((code
== EQ_EXPR
) ? 0 : 1);
1457 /* We know the result of a comparison is always one or zero. */
1467 code
= swap_tree_comparison (code
);
1474 const widest_int
&o1val
= swap_p
? r2val
: r1val
;
1475 const widest_int
&o1mask
= swap_p
? r2mask
: r1mask
;
1476 const widest_int
&o2val
= swap_p
? r1val
: r2val
;
1477 const widest_int
&o2mask
= swap_p
? r1mask
: r2mask
;
1479 /* If the most significant bits are not known we know nothing. */
1480 if (wi::neg_p (o1mask
) || wi::neg_p (o2mask
))
1483 /* For comparisons the signedness is in the comparison operands. */
1486 /* If we know the most significant bits we know the values
1487 value ranges by means of treating varying bits as zero
1488 or one. Do a cross comparison of the max/min pairs. */
1489 maxmin
= wi::cmp (o1val
| o1mask
, o2val
.and_not (o2mask
), sgn
);
1490 minmax
= wi::cmp (o1val
.and_not (o1mask
), o2val
| o2mask
, sgn
);
1491 if (maxmin
< 0) /* o1 is less than o2. */
1496 else if (minmax
> 0) /* o1 is not less or equal to o2. */
1501 else if (maxmin
== minmax
) /* o1 and o2 are equal. */
1503 /* This probably should never happen as we'd have
1504 folded the thing during fully constant value folding. */
1506 *val
= (code
== LE_EXPR
? 1 : 0);
1510 /* We know the result of a comparison is always one or zero. */
1521 /* Return the propagation value when applying the operation CODE to
1522 the value RHS yielding type TYPE. */
1524 static ccp_prop_value_t
1525 bit_value_unop (enum tree_code code
, tree type
, tree rhs
)
1527 ccp_prop_value_t rval
= get_value_for_expr (rhs
, true);
1528 widest_int value
, mask
;
1529 ccp_prop_value_t val
;
1531 if (rval
.lattice_val
== UNDEFINED
)
1534 gcc_assert ((rval
.lattice_val
== CONSTANT
1535 && TREE_CODE (rval
.value
) == INTEGER_CST
)
1536 || wi::sext (rval
.mask
, TYPE_PRECISION (TREE_TYPE (rhs
))) == -1);
1537 bit_value_unop (code
, TYPE_SIGN (type
), TYPE_PRECISION (type
), &value
, &mask
,
1538 TYPE_SIGN (TREE_TYPE (rhs
)), TYPE_PRECISION (TREE_TYPE (rhs
)),
1539 value_to_wide_int (rval
), rval
.mask
);
1540 if (wi::sext (mask
, TYPE_PRECISION (type
)) != -1)
1542 val
.lattice_val
= CONSTANT
;
1544 /* ??? Delay building trees here. */
1545 val
.value
= wide_int_to_tree (type
, value
);
1549 val
.lattice_val
= VARYING
;
1550 val
.value
= NULL_TREE
;
1556 /* Return the propagation value when applying the operation CODE to
1557 the values RHS1 and RHS2 yielding type TYPE. */
1559 static ccp_prop_value_t
1560 bit_value_binop (enum tree_code code
, tree type
, tree rhs1
, tree rhs2
)
1562 ccp_prop_value_t r1val
= get_value_for_expr (rhs1
, true);
1563 ccp_prop_value_t r2val
= get_value_for_expr (rhs2
, true);
1564 widest_int value
, mask
;
1565 ccp_prop_value_t val
;
1567 if (r1val
.lattice_val
== UNDEFINED
1568 || r2val
.lattice_val
== UNDEFINED
)
1570 val
.lattice_val
= VARYING
;
1571 val
.value
= NULL_TREE
;
1576 gcc_assert ((r1val
.lattice_val
== CONSTANT
1577 && TREE_CODE (r1val
.value
) == INTEGER_CST
)
1578 || wi::sext (r1val
.mask
,
1579 TYPE_PRECISION (TREE_TYPE (rhs1
))) == -1);
1580 gcc_assert ((r2val
.lattice_val
== CONSTANT
1581 && TREE_CODE (r2val
.value
) == INTEGER_CST
)
1582 || wi::sext (r2val
.mask
,
1583 TYPE_PRECISION (TREE_TYPE (rhs2
))) == -1);
1584 bit_value_binop (code
, TYPE_SIGN (type
), TYPE_PRECISION (type
), &value
, &mask
,
1585 TYPE_SIGN (TREE_TYPE (rhs1
)), TYPE_PRECISION (TREE_TYPE (rhs1
)),
1586 value_to_wide_int (r1val
), r1val
.mask
,
1587 TYPE_SIGN (TREE_TYPE (rhs2
)), TYPE_PRECISION (TREE_TYPE (rhs2
)),
1588 value_to_wide_int (r2val
), r2val
.mask
);
1590 if (wi::sext (mask
, TYPE_PRECISION (type
)) != -1)
1592 val
.lattice_val
= CONSTANT
;
1594 /* ??? Delay building trees here. */
1595 val
.value
= wide_int_to_tree (type
, value
);
1599 val
.lattice_val
= VARYING
;
1600 val
.value
= NULL_TREE
;
1606 /* Return the propagation value for __builtin_assume_aligned
1607 and functions with assume_aligned or alloc_aligned attribute.
1608 For __builtin_assume_aligned, ATTR is NULL_TREE,
1609 for assume_aligned attribute ATTR is non-NULL and ALLOC_ALIGNED
1610 is false, for alloc_aligned attribute ATTR is non-NULL and
1611 ALLOC_ALIGNED is true. */
1613 static ccp_prop_value_t
1614 bit_value_assume_aligned (gimple
*stmt
, tree attr
, ccp_prop_value_t ptrval
,
1617 tree align
, misalign
= NULL_TREE
, type
;
1618 unsigned HOST_WIDE_INT aligni
, misaligni
= 0;
1619 ccp_prop_value_t alignval
;
1620 widest_int value
, mask
;
1621 ccp_prop_value_t val
;
1623 if (attr
== NULL_TREE
)
1625 tree ptr
= gimple_call_arg (stmt
, 0);
1626 type
= TREE_TYPE (ptr
);
1627 ptrval
= get_value_for_expr (ptr
, true);
1631 tree lhs
= gimple_call_lhs (stmt
);
1632 type
= TREE_TYPE (lhs
);
1635 if (ptrval
.lattice_val
== UNDEFINED
)
1637 gcc_assert ((ptrval
.lattice_val
== CONSTANT
1638 && TREE_CODE (ptrval
.value
) == INTEGER_CST
)
1639 || wi::sext (ptrval
.mask
, TYPE_PRECISION (type
)) == -1);
1640 if (attr
== NULL_TREE
)
1642 /* Get aligni and misaligni from __builtin_assume_aligned. */
1643 align
= gimple_call_arg (stmt
, 1);
1644 if (!tree_fits_uhwi_p (align
))
1646 aligni
= tree_to_uhwi (align
);
1647 if (gimple_call_num_args (stmt
) > 2)
1649 misalign
= gimple_call_arg (stmt
, 2);
1650 if (!tree_fits_uhwi_p (misalign
))
1652 misaligni
= tree_to_uhwi (misalign
);
1657 /* Get aligni and misaligni from assume_aligned or
1658 alloc_align attributes. */
1659 if (TREE_VALUE (attr
) == NULL_TREE
)
1661 attr
= TREE_VALUE (attr
);
1662 align
= TREE_VALUE (attr
);
1663 if (!tree_fits_uhwi_p (align
))
1665 aligni
= tree_to_uhwi (align
);
1668 if (aligni
== 0 || aligni
> gimple_call_num_args (stmt
))
1670 align
= gimple_call_arg (stmt
, aligni
- 1);
1671 if (!tree_fits_uhwi_p (align
))
1673 aligni
= tree_to_uhwi (align
);
1675 else if (TREE_CHAIN (attr
) && TREE_VALUE (TREE_CHAIN (attr
)))
1677 misalign
= TREE_VALUE (TREE_CHAIN (attr
));
1678 if (!tree_fits_uhwi_p (misalign
))
1680 misaligni
= tree_to_uhwi (misalign
);
1683 if (aligni
<= 1 || (aligni
& (aligni
- 1)) != 0 || misaligni
>= aligni
)
1686 align
= build_int_cst_type (type
, -aligni
);
1687 alignval
= get_value_for_expr (align
, true);
1688 bit_value_binop (BIT_AND_EXPR
, TYPE_SIGN (type
), TYPE_PRECISION (type
), &value
, &mask
,
1689 TYPE_SIGN (type
), TYPE_PRECISION (type
), value_to_wide_int (ptrval
), ptrval
.mask
,
1690 TYPE_SIGN (type
), TYPE_PRECISION (type
), value_to_wide_int (alignval
), alignval
.mask
);
1692 if (wi::sext (mask
, TYPE_PRECISION (type
)) != -1)
1694 val
.lattice_val
= CONSTANT
;
1696 gcc_assert ((mask
.to_uhwi () & (aligni
- 1)) == 0);
1697 gcc_assert ((value
.to_uhwi () & (aligni
- 1)) == 0);
1699 /* ??? Delay building trees here. */
1700 val
.value
= wide_int_to_tree (type
, value
);
1704 val
.lattice_val
= VARYING
;
1705 val
.value
= NULL_TREE
;
1711 /* Evaluate statement STMT.
1712 Valid only for assignments, calls, conditionals, and switches. */
1714 static ccp_prop_value_t
1715 evaluate_stmt (gimple
*stmt
)
1717 ccp_prop_value_t val
;
1718 tree simplified
= NULL_TREE
;
1719 ccp_lattice_t likelyvalue
= likely_value (stmt
);
1720 bool is_constant
= false;
1723 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1725 fprintf (dump_file
, "which is likely ");
1726 switch (likelyvalue
)
1729 fprintf (dump_file
, "CONSTANT");
1732 fprintf (dump_file
, "UNDEFINED");
1735 fprintf (dump_file
, "VARYING");
1739 fprintf (dump_file
, "\n");
1742 /* If the statement is likely to have a CONSTANT result, then try
1743 to fold the statement to determine the constant value. */
1744 /* FIXME. This is the only place that we call ccp_fold.
1745 Since likely_value never returns CONSTANT for calls, we will
1746 not attempt to fold them, including builtins that may profit. */
1747 if (likelyvalue
== CONSTANT
)
1749 fold_defer_overflow_warnings ();
1750 simplified
= ccp_fold (stmt
);
1752 && TREE_CODE (simplified
) == SSA_NAME
1753 /* We may not use values of something that may be simulated again,
1754 see valueize_op_1. */
1755 && (SSA_NAME_IS_DEFAULT_DEF (simplified
)
1756 || ! prop_simulate_again_p (SSA_NAME_DEF_STMT (simplified
))))
1758 ccp_prop_value_t
*val
= get_value (simplified
);
1759 if (val
&& val
->lattice_val
!= VARYING
)
1761 fold_undefer_overflow_warnings (true, stmt
, 0);
1765 is_constant
= simplified
&& is_gimple_min_invariant (simplified
);
1766 fold_undefer_overflow_warnings (is_constant
, stmt
, 0);
1769 /* The statement produced a constant value. */
1770 val
.lattice_val
= CONSTANT
;
1771 val
.value
= simplified
;
1776 /* If the statement is likely to have a VARYING result, then do not
1777 bother folding the statement. */
1778 else if (likelyvalue
== VARYING
)
1780 enum gimple_code code
= gimple_code (stmt
);
1781 if (code
== GIMPLE_ASSIGN
)
1783 enum tree_code subcode
= gimple_assign_rhs_code (stmt
);
1785 /* Other cases cannot satisfy is_gimple_min_invariant
1787 if (get_gimple_rhs_class (subcode
) == GIMPLE_SINGLE_RHS
)
1788 simplified
= gimple_assign_rhs1 (stmt
);
1790 else if (code
== GIMPLE_SWITCH
)
1791 simplified
= gimple_switch_index (as_a
<gswitch
*> (stmt
));
1793 /* These cannot satisfy is_gimple_min_invariant without folding. */
1794 gcc_assert (code
== GIMPLE_CALL
|| code
== GIMPLE_COND
);
1795 is_constant
= simplified
&& is_gimple_min_invariant (simplified
);
1798 /* The statement produced a constant value. */
1799 val
.lattice_val
= CONSTANT
;
1800 val
.value
= simplified
;
1804 /* If the statement result is likely UNDEFINED, make it so. */
1805 else if (likelyvalue
== UNDEFINED
)
1807 val
.lattice_val
= UNDEFINED
;
1808 val
.value
= NULL_TREE
;
1813 /* Resort to simplification for bitwise tracking. */
1814 if (flag_tree_bit_ccp
1815 && (likelyvalue
== CONSTANT
|| is_gimple_call (stmt
)
1816 || (gimple_assign_single_p (stmt
)
1817 && gimple_assign_rhs_code (stmt
) == ADDR_EXPR
))
1820 enum gimple_code code
= gimple_code (stmt
);
1821 val
.lattice_val
= VARYING
;
1822 val
.value
= NULL_TREE
;
1824 if (code
== GIMPLE_ASSIGN
)
1826 enum tree_code subcode
= gimple_assign_rhs_code (stmt
);
1827 tree rhs1
= gimple_assign_rhs1 (stmt
);
1828 tree lhs
= gimple_assign_lhs (stmt
);
1829 if ((INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
1830 || POINTER_TYPE_P (TREE_TYPE (lhs
)))
1831 && (INTEGRAL_TYPE_P (TREE_TYPE (rhs1
))
1832 || POINTER_TYPE_P (TREE_TYPE (rhs1
))))
1833 switch (get_gimple_rhs_class (subcode
))
1835 case GIMPLE_SINGLE_RHS
:
1836 val
= get_value_for_expr (rhs1
, true);
1839 case GIMPLE_UNARY_RHS
:
1840 val
= bit_value_unop (subcode
, TREE_TYPE (lhs
), rhs1
);
1843 case GIMPLE_BINARY_RHS
:
1844 val
= bit_value_binop (subcode
, TREE_TYPE (lhs
), rhs1
,
1845 gimple_assign_rhs2 (stmt
));
1851 else if (code
== GIMPLE_COND
)
1853 enum tree_code code
= gimple_cond_code (stmt
);
1854 tree rhs1
= gimple_cond_lhs (stmt
);
1855 tree rhs2
= gimple_cond_rhs (stmt
);
1856 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1
))
1857 || POINTER_TYPE_P (TREE_TYPE (rhs1
)))
1858 val
= bit_value_binop (code
, TREE_TYPE (rhs1
), rhs1
, rhs2
);
1860 else if (gimple_call_builtin_p (stmt
, BUILT_IN_NORMAL
))
1862 tree fndecl
= gimple_call_fndecl (stmt
);
1863 switch (DECL_FUNCTION_CODE (fndecl
))
1865 case BUILT_IN_MALLOC
:
1866 case BUILT_IN_REALLOC
:
1867 case BUILT_IN_CALLOC
:
1868 case BUILT_IN_STRDUP
:
1869 case BUILT_IN_STRNDUP
:
1870 val
.lattice_val
= CONSTANT
;
1871 val
.value
= build_int_cst (TREE_TYPE (gimple_get_lhs (stmt
)), 0);
1872 val
.mask
= ~((HOST_WIDE_INT
) MALLOC_ABI_ALIGNMENT
1873 / BITS_PER_UNIT
- 1);
1876 case BUILT_IN_ALLOCA
:
1877 case BUILT_IN_ALLOCA_WITH_ALIGN
:
1878 align
= (DECL_FUNCTION_CODE (fndecl
) == BUILT_IN_ALLOCA_WITH_ALIGN
1879 ? TREE_INT_CST_LOW (gimple_call_arg (stmt
, 1))
1880 : BIGGEST_ALIGNMENT
);
1881 val
.lattice_val
= CONSTANT
;
1882 val
.value
= build_int_cst (TREE_TYPE (gimple_get_lhs (stmt
)), 0);
1883 val
.mask
= ~((HOST_WIDE_INT
) align
/ BITS_PER_UNIT
- 1);
1886 /* These builtins return their first argument, unmodified. */
1887 case BUILT_IN_MEMCPY
:
1888 case BUILT_IN_MEMMOVE
:
1889 case BUILT_IN_MEMSET
:
1890 case BUILT_IN_STRCPY
:
1891 case BUILT_IN_STRNCPY
:
1892 case BUILT_IN_MEMCPY_CHK
:
1893 case BUILT_IN_MEMMOVE_CHK
:
1894 case BUILT_IN_MEMSET_CHK
:
1895 case BUILT_IN_STRCPY_CHK
:
1896 case BUILT_IN_STRNCPY_CHK
:
1897 val
= get_value_for_expr (gimple_call_arg (stmt
, 0), true);
1900 case BUILT_IN_ASSUME_ALIGNED
:
1901 val
= bit_value_assume_aligned (stmt
, NULL_TREE
, val
, false);
1904 case BUILT_IN_ALIGNED_ALLOC
:
1906 tree align
= get_constant_value (gimple_call_arg (stmt
, 0));
1908 && tree_fits_uhwi_p (align
))
1910 unsigned HOST_WIDE_INT aligni
= tree_to_uhwi (align
);
1912 /* align must be power-of-two */
1913 && (aligni
& (aligni
- 1)) == 0)
1915 val
.lattice_val
= CONSTANT
;
1916 val
.value
= build_int_cst (ptr_type_node
, 0);
1926 if (is_gimple_call (stmt
) && gimple_call_lhs (stmt
))
1928 tree fntype
= gimple_call_fntype (stmt
);
1931 tree attrs
= lookup_attribute ("assume_aligned",
1932 TYPE_ATTRIBUTES (fntype
));
1934 val
= bit_value_assume_aligned (stmt
, attrs
, val
, false);
1935 attrs
= lookup_attribute ("alloc_align",
1936 TYPE_ATTRIBUTES (fntype
));
1938 val
= bit_value_assume_aligned (stmt
, attrs
, val
, true);
1941 is_constant
= (val
.lattice_val
== CONSTANT
);
1944 if (flag_tree_bit_ccp
1945 && ((is_constant
&& TREE_CODE (val
.value
) == INTEGER_CST
)
1947 && gimple_get_lhs (stmt
)
1948 && TREE_CODE (gimple_get_lhs (stmt
)) == SSA_NAME
)
1950 tree lhs
= gimple_get_lhs (stmt
);
1951 wide_int nonzero_bits
= get_nonzero_bits (lhs
);
1952 if (nonzero_bits
!= -1)
1956 val
.lattice_val
= CONSTANT
;
1957 val
.value
= build_zero_cst (TREE_TYPE (lhs
));
1958 val
.mask
= extend_mask (nonzero_bits
, TYPE_SIGN (TREE_TYPE (lhs
)));
1963 if (wi::bit_and_not (val
.value
, nonzero_bits
) != 0)
1964 val
.value
= wide_int_to_tree (TREE_TYPE (lhs
),
1965 nonzero_bits
& val
.value
);
1966 if (nonzero_bits
== 0)
1969 val
.mask
= val
.mask
& extend_mask (nonzero_bits
,
1970 TYPE_SIGN (TREE_TYPE (lhs
)));
1975 /* The statement produced a nonconstant value. */
1978 /* The statement produced a copy. */
1979 if (simplified
&& TREE_CODE (simplified
) == SSA_NAME
1980 && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (simplified
))
1982 val
.lattice_val
= CONSTANT
;
1983 val
.value
= simplified
;
1986 /* The statement is VARYING. */
1989 val
.lattice_val
= VARYING
;
1990 val
.value
= NULL_TREE
;
1998 typedef hash_table
<nofree_ptr_hash
<gimple
> > gimple_htab
;
2000 /* Given a BUILT_IN_STACK_SAVE value SAVED_VAL, insert a clobber of VAR before
2001 each matching BUILT_IN_STACK_RESTORE. Mark visited phis in VISITED. */
2004 insert_clobber_before_stack_restore (tree saved_val
, tree var
,
2005 gimple_htab
**visited
)
2008 gassign
*clobber_stmt
;
2010 imm_use_iterator iter
;
2011 gimple_stmt_iterator i
;
2014 FOR_EACH_IMM_USE_STMT (stmt
, iter
, saved_val
)
2015 if (gimple_call_builtin_p (stmt
, BUILT_IN_STACK_RESTORE
))
2017 clobber
= build_constructor (TREE_TYPE (var
),
2019 TREE_THIS_VOLATILE (clobber
) = 1;
2020 clobber_stmt
= gimple_build_assign (var
, clobber
);
2022 i
= gsi_for_stmt (stmt
);
2023 gsi_insert_before (&i
, clobber_stmt
, GSI_SAME_STMT
);
2025 else if (gimple_code (stmt
) == GIMPLE_PHI
)
2028 *visited
= new gimple_htab (10);
2030 slot
= (*visited
)->find_slot (stmt
, INSERT
);
2035 insert_clobber_before_stack_restore (gimple_phi_result (stmt
), var
,
2038 else if (gimple_assign_ssa_name_copy_p (stmt
))
2039 insert_clobber_before_stack_restore (gimple_assign_lhs (stmt
), var
,
2041 else if (chkp_gimple_call_builtin_p (stmt
, BUILT_IN_CHKP_BNDRET
))
2044 gcc_assert (is_gimple_debug (stmt
));
2047 /* Advance the iterator to the previous non-debug gimple statement in the same
2048 or dominating basic block. */
2051 gsi_prev_dom_bb_nondebug (gimple_stmt_iterator
*i
)
2055 gsi_prev_nondebug (i
);
2056 while (gsi_end_p (*i
))
2058 dom
= get_immediate_dominator (CDI_DOMINATORS
, i
->bb
);
2059 if (dom
== NULL
|| dom
== ENTRY_BLOCK_PTR_FOR_FN (cfun
))
2062 *i
= gsi_last_bb (dom
);
2066 /* Find a BUILT_IN_STACK_SAVE dominating gsi_stmt (I), and insert
2067 a clobber of VAR before each matching BUILT_IN_STACK_RESTORE.
2069 It is possible that BUILT_IN_STACK_SAVE cannot be find in a dominator when a
2070 previous pass (such as DOM) duplicated it along multiple paths to a BB. In
2071 that case the function gives up without inserting the clobbers. */
2074 insert_clobbers_for_var (gimple_stmt_iterator i
, tree var
)
2078 gimple_htab
*visited
= NULL
;
2080 for (; !gsi_end_p (i
); gsi_prev_dom_bb_nondebug (&i
))
2082 stmt
= gsi_stmt (i
);
2084 if (!gimple_call_builtin_p (stmt
, BUILT_IN_STACK_SAVE
))
2087 saved_val
= gimple_call_lhs (stmt
);
2088 if (saved_val
== NULL_TREE
)
2091 insert_clobber_before_stack_restore (saved_val
, var
, &visited
);
2098 /* Detects a __builtin_alloca_with_align with constant size argument. Declares
2099 fixed-size array and returns the address, if found, otherwise returns
2103 fold_builtin_alloca_with_align (gimple
*stmt
)
2105 unsigned HOST_WIDE_INT size
, threshold
, n_elem
;
2106 tree lhs
, arg
, block
, var
, elem_type
, array_type
;
2109 lhs
= gimple_call_lhs (stmt
);
2110 if (lhs
== NULL_TREE
)
2113 /* Detect constant argument. */
2114 arg
= get_constant_value (gimple_call_arg (stmt
, 0));
2115 if (arg
== NULL_TREE
2116 || TREE_CODE (arg
) != INTEGER_CST
2117 || !tree_fits_uhwi_p (arg
))
2120 size
= tree_to_uhwi (arg
);
2122 /* Heuristic: don't fold large allocas. */
2123 threshold
= (unsigned HOST_WIDE_INT
)PARAM_VALUE (PARAM_LARGE_STACK_FRAME
);
2124 /* In case the alloca is located at function entry, it has the same lifetime
2125 as a declared array, so we allow a larger size. */
2126 block
= gimple_block (stmt
);
2127 if (!(cfun
->after_inlining
2129 && TREE_CODE (BLOCK_SUPERCONTEXT (block
)) == FUNCTION_DECL
))
2131 if (size
> threshold
)
2134 /* Declare array. */
2135 elem_type
= build_nonstandard_integer_type (BITS_PER_UNIT
, 1);
2136 n_elem
= size
* 8 / BITS_PER_UNIT
;
2137 array_type
= build_array_type_nelts (elem_type
, n_elem
);
2138 var
= create_tmp_var (array_type
);
2139 SET_DECL_ALIGN (var
, TREE_INT_CST_LOW (gimple_call_arg (stmt
, 1)));
2141 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (lhs
);
2142 if (pi
!= NULL
&& !pi
->pt
.anything
)
2146 singleton_p
= pt_solution_singleton_or_null_p (&pi
->pt
, &uid
);
2147 gcc_assert (singleton_p
);
2148 SET_DECL_PT_UID (var
, uid
);
2152 /* Fold alloca to the address of the array. */
2153 return fold_convert (TREE_TYPE (lhs
), build_fold_addr_expr (var
));
2156 /* Fold the stmt at *GSI with CCP specific information that propagating
2157 and regular folding does not catch. */
2160 ccp_fold_stmt (gimple_stmt_iterator
*gsi
)
2162 gimple
*stmt
= gsi_stmt (*gsi
);
2164 switch (gimple_code (stmt
))
2168 gcond
*cond_stmt
= as_a
<gcond
*> (stmt
);
2169 ccp_prop_value_t val
;
2170 /* Statement evaluation will handle type mismatches in constants
2171 more gracefully than the final propagation. This allows us to
2172 fold more conditionals here. */
2173 val
= evaluate_stmt (stmt
);
2174 if (val
.lattice_val
!= CONSTANT
2180 fprintf (dump_file
, "Folding predicate ");
2181 print_gimple_expr (dump_file
, stmt
, 0, 0);
2182 fprintf (dump_file
, " to ");
2183 print_generic_expr (dump_file
, val
.value
, 0);
2184 fprintf (dump_file
, "\n");
2187 if (integer_zerop (val
.value
))
2188 gimple_cond_make_false (cond_stmt
);
2190 gimple_cond_make_true (cond_stmt
);
2197 tree lhs
= gimple_call_lhs (stmt
);
2198 int flags
= gimple_call_flags (stmt
);
2201 bool changed
= false;
2204 /* If the call was folded into a constant make sure it goes
2205 away even if we cannot propagate into all uses because of
2208 && TREE_CODE (lhs
) == SSA_NAME
2209 && (val
= get_constant_value (lhs
))
2210 /* Don't optimize away calls that have side-effects. */
2211 && (flags
& (ECF_CONST
|ECF_PURE
)) != 0
2212 && (flags
& ECF_LOOPING_CONST_OR_PURE
) == 0)
2214 tree new_rhs
= unshare_expr (val
);
2216 if (!useless_type_conversion_p (TREE_TYPE (lhs
),
2217 TREE_TYPE (new_rhs
)))
2218 new_rhs
= fold_convert (TREE_TYPE (lhs
), new_rhs
);
2219 res
= update_call_from_tree (gsi
, new_rhs
);
2224 /* Internal calls provide no argument types, so the extra laxity
2225 for normal calls does not apply. */
2226 if (gimple_call_internal_p (stmt
))
2229 /* The heuristic of fold_builtin_alloca_with_align differs before and
2230 after inlining, so we don't require the arg to be changed into a
2231 constant for folding, but just to be constant. */
2232 if (gimple_call_builtin_p (stmt
, BUILT_IN_ALLOCA_WITH_ALIGN
))
2234 tree new_rhs
= fold_builtin_alloca_with_align (stmt
);
2237 bool res
= update_call_from_tree (gsi
, new_rhs
);
2238 tree var
= TREE_OPERAND (TREE_OPERAND (new_rhs
, 0),0);
2240 insert_clobbers_for_var (*gsi
, var
);
2245 /* Propagate into the call arguments. Compared to replace_uses_in
2246 this can use the argument slot types for type verification
2247 instead of the current argument type. We also can safely
2248 drop qualifiers here as we are dealing with constants anyway. */
2249 argt
= TYPE_ARG_TYPES (gimple_call_fntype (stmt
));
2250 for (i
= 0; i
< gimple_call_num_args (stmt
) && argt
;
2251 ++i
, argt
= TREE_CHAIN (argt
))
2253 tree arg
= gimple_call_arg (stmt
, i
);
2254 if (TREE_CODE (arg
) == SSA_NAME
2255 && (val
= get_constant_value (arg
))
2256 && useless_type_conversion_p
2257 (TYPE_MAIN_VARIANT (TREE_VALUE (argt
)),
2258 TYPE_MAIN_VARIANT (TREE_TYPE (val
))))
2260 gimple_call_set_arg (stmt
, i
, unshare_expr (val
));
2270 tree lhs
= gimple_assign_lhs (stmt
);
2273 /* If we have a load that turned out to be constant replace it
2274 as we cannot propagate into all uses in all cases. */
2275 if (gimple_assign_single_p (stmt
)
2276 && TREE_CODE (lhs
) == SSA_NAME
2277 && (val
= get_constant_value (lhs
)))
2279 tree rhs
= unshare_expr (val
);
2280 if (!useless_type_conversion_p (TREE_TYPE (lhs
), TREE_TYPE (rhs
)))
2281 rhs
= fold_build1 (VIEW_CONVERT_EXPR
, TREE_TYPE (lhs
), rhs
);
2282 gimple_assign_set_rhs_from_tree (gsi
, rhs
);
2294 /* Visit the assignment statement STMT. Set the value of its LHS to the
2295 value computed by the RHS and store LHS in *OUTPUT_P. If STMT
2296 creates virtual definitions, set the value of each new name to that
2297 of the RHS (if we can derive a constant out of the RHS).
2298 Value-returning call statements also perform an assignment, and
2299 are handled here. */
2301 static enum ssa_prop_result
2302 visit_assignment (gimple
*stmt
, tree
*output_p
)
2304 ccp_prop_value_t val
;
2305 enum ssa_prop_result retval
= SSA_PROP_NOT_INTERESTING
;
2307 tree lhs
= gimple_get_lhs (stmt
);
2308 if (TREE_CODE (lhs
) == SSA_NAME
)
2310 /* Evaluate the statement, which could be
2311 either a GIMPLE_ASSIGN or a GIMPLE_CALL. */
2312 val
= evaluate_stmt (stmt
);
2314 /* If STMT is an assignment to an SSA_NAME, we only have one
2316 if (set_lattice_value (lhs
, &val
))
2319 if (val
.lattice_val
== VARYING
)
2320 retval
= SSA_PROP_VARYING
;
2322 retval
= SSA_PROP_INTERESTING
;
2330 /* Visit the conditional statement STMT. Return SSA_PROP_INTERESTING
2331 if it can determine which edge will be taken. Otherwise, return
2332 SSA_PROP_VARYING. */
2334 static enum ssa_prop_result
2335 visit_cond_stmt (gimple
*stmt
, edge
*taken_edge_p
)
2337 ccp_prop_value_t val
;
2340 block
= gimple_bb (stmt
);
2341 val
= evaluate_stmt (stmt
);
2342 if (val
.lattice_val
!= CONSTANT
2344 return SSA_PROP_VARYING
;
2346 /* Find which edge out of the conditional block will be taken and add it
2347 to the worklist. If no single edge can be determined statically,
2348 return SSA_PROP_VARYING to feed all the outgoing edges to the
2349 propagation engine. */
2350 *taken_edge_p
= find_taken_edge (block
, val
.value
);
2352 return SSA_PROP_INTERESTING
;
2354 return SSA_PROP_VARYING
;
2358 /* Evaluate statement STMT. If the statement produces an output value and
2359 its evaluation changes the lattice value of its output, return
2360 SSA_PROP_INTERESTING and set *OUTPUT_P to the SSA_NAME holding the
2363 If STMT is a conditional branch and we can determine its truth
2364 value, set *TAKEN_EDGE_P accordingly. If STMT produces a varying
2365 value, return SSA_PROP_VARYING. */
2367 static enum ssa_prop_result
2368 ccp_visit_stmt (gimple
*stmt
, edge
*taken_edge_p
, tree
*output_p
)
2373 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2375 fprintf (dump_file
, "\nVisiting statement:\n");
2376 print_gimple_stmt (dump_file
, stmt
, 0, dump_flags
);
2379 switch (gimple_code (stmt
))
2382 /* If the statement is an assignment that produces a single
2383 output value, evaluate its RHS to see if the lattice value of
2384 its output has changed. */
2385 return visit_assignment (stmt
, output_p
);
2388 /* A value-returning call also performs an assignment. */
2389 if (gimple_call_lhs (stmt
) != NULL_TREE
)
2390 return visit_assignment (stmt
, output_p
);
2395 /* If STMT is a conditional branch, see if we can determine
2396 which branch will be taken. */
2397 /* FIXME. It appears that we should be able to optimize
2398 computed GOTOs here as well. */
2399 return visit_cond_stmt (stmt
, taken_edge_p
);
2405 /* Any other kind of statement is not interesting for constant
2406 propagation and, therefore, not worth simulating. */
2407 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2408 fprintf (dump_file
, "No interesting values produced. Marked VARYING.\n");
2410 /* Definitions made by statements other than assignments to
2411 SSA_NAMEs represent unknown modifications to their outputs.
2412 Mark them VARYING. */
2413 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, iter
, SSA_OP_ALL_DEFS
)
2414 set_value_varying (def
);
2416 return SSA_PROP_VARYING
;
2420 /* Main entry point for SSA Conditional Constant Propagation. If NONZERO_P,
2421 record nonzero bits. */
2424 do_ssa_ccp (bool nonzero_p
)
2426 unsigned int todo
= 0;
2427 calculate_dominance_info (CDI_DOMINATORS
);
2430 ssa_propagate (ccp_visit_stmt
, ccp_visit_phi_node
);
2431 if (ccp_finalize (nonzero_p
|| flag_ipa_bit_cp
))
2433 todo
= (TODO_cleanup_cfg
| TODO_update_ssa
);
2435 /* ccp_finalize does not preserve loop-closed ssa. */
2436 loops_state_clear (LOOP_CLOSED_SSA
);
2439 free_dominance_info (CDI_DOMINATORS
);
2446 const pass_data pass_data_ccp
=
2448 GIMPLE_PASS
, /* type */
2450 OPTGROUP_NONE
, /* optinfo_flags */
2451 TV_TREE_CCP
, /* tv_id */
2452 ( PROP_cfg
| PROP_ssa
), /* properties_required */
2453 0, /* properties_provided */
2454 0, /* properties_destroyed */
2455 0, /* todo_flags_start */
2456 TODO_update_address_taken
, /* todo_flags_finish */
2459 class pass_ccp
: public gimple_opt_pass
2462 pass_ccp (gcc::context
*ctxt
)
2463 : gimple_opt_pass (pass_data_ccp
, ctxt
), nonzero_p (false)
2466 /* opt_pass methods: */
2467 opt_pass
* clone () { return new pass_ccp (m_ctxt
); }
2468 void set_pass_param (unsigned int n
, bool param
)
2470 gcc_assert (n
== 0);
2473 virtual bool gate (function
*) { return flag_tree_ccp
!= 0; }
2474 virtual unsigned int execute (function
*) { return do_ssa_ccp (nonzero_p
); }
2477 /* Determines whether the pass instance records nonzero bits. */
2479 }; // class pass_ccp
2484 make_pass_ccp (gcc::context
*ctxt
)
2486 return new pass_ccp (ctxt
);
2491 /* Try to optimize out __builtin_stack_restore. Optimize it out
2492 if there is another __builtin_stack_restore in the same basic
2493 block and no calls or ASM_EXPRs are in between, or if this block's
2494 only outgoing edge is to EXIT_BLOCK and there are no calls or
2495 ASM_EXPRs after this __builtin_stack_restore. */
2498 optimize_stack_restore (gimple_stmt_iterator i
)
2503 basic_block bb
= gsi_bb (i
);
2504 gimple
*call
= gsi_stmt (i
);
2506 if (gimple_code (call
) != GIMPLE_CALL
2507 || gimple_call_num_args (call
) != 1
2508 || TREE_CODE (gimple_call_arg (call
, 0)) != SSA_NAME
2509 || !POINTER_TYPE_P (TREE_TYPE (gimple_call_arg (call
, 0))))
2512 for (gsi_next (&i
); !gsi_end_p (i
); gsi_next (&i
))
2514 stmt
= gsi_stmt (i
);
2515 if (gimple_code (stmt
) == GIMPLE_ASM
)
2517 if (gimple_code (stmt
) != GIMPLE_CALL
)
2520 callee
= gimple_call_fndecl (stmt
);
2522 || DECL_BUILT_IN_CLASS (callee
) != BUILT_IN_NORMAL
2523 /* All regular builtins are ok, just obviously not alloca. */
2524 || DECL_FUNCTION_CODE (callee
) == BUILT_IN_ALLOCA
2525 || DECL_FUNCTION_CODE (callee
) == BUILT_IN_ALLOCA_WITH_ALIGN
)
2528 if (DECL_FUNCTION_CODE (callee
) == BUILT_IN_STACK_RESTORE
)
2529 goto second_stack_restore
;
2535 /* Allow one successor of the exit block, or zero successors. */
2536 switch (EDGE_COUNT (bb
->succs
))
2541 if (single_succ_edge (bb
)->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
2547 second_stack_restore
:
2549 /* If there's exactly one use, then zap the call to __builtin_stack_save.
2550 If there are multiple uses, then the last one should remove the call.
2551 In any case, whether the call to __builtin_stack_save can be removed
2552 or not is irrelevant to removing the call to __builtin_stack_restore. */
2553 if (has_single_use (gimple_call_arg (call
, 0)))
2555 gimple
*stack_save
= SSA_NAME_DEF_STMT (gimple_call_arg (call
, 0));
2556 if (is_gimple_call (stack_save
))
2558 callee
= gimple_call_fndecl (stack_save
);
2560 && DECL_BUILT_IN_CLASS (callee
) == BUILT_IN_NORMAL
2561 && DECL_FUNCTION_CODE (callee
) == BUILT_IN_STACK_SAVE
)
2563 gimple_stmt_iterator stack_save_gsi
;
2566 stack_save_gsi
= gsi_for_stmt (stack_save
);
2567 rhs
= build_int_cst (TREE_TYPE (gimple_call_arg (call
, 0)), 0);
2568 update_call_from_tree (&stack_save_gsi
, rhs
);
2573 /* No effect, so the statement will be deleted. */
2574 return integer_zero_node
;
2577 /* If va_list type is a simple pointer and nothing special is needed,
2578 optimize __builtin_va_start (&ap, 0) into ap = __builtin_next_arg (0),
2579 __builtin_va_end (&ap) out as NOP and __builtin_va_copy into a simple
2580 pointer assignment. */
2583 optimize_stdarg_builtin (gimple
*call
)
2585 tree callee
, lhs
, rhs
, cfun_va_list
;
2586 bool va_list_simple_ptr
;
2587 location_t loc
= gimple_location (call
);
2589 if (gimple_code (call
) != GIMPLE_CALL
)
2592 callee
= gimple_call_fndecl (call
);
2594 cfun_va_list
= targetm
.fn_abi_va_list (callee
);
2595 va_list_simple_ptr
= POINTER_TYPE_P (cfun_va_list
)
2596 && (TREE_TYPE (cfun_va_list
) == void_type_node
2597 || TREE_TYPE (cfun_va_list
) == char_type_node
);
2599 switch (DECL_FUNCTION_CODE (callee
))
2601 case BUILT_IN_VA_START
:
2602 if (!va_list_simple_ptr
2603 || targetm
.expand_builtin_va_start
!= NULL
2604 || !builtin_decl_explicit_p (BUILT_IN_NEXT_ARG
))
2607 if (gimple_call_num_args (call
) != 2)
2610 lhs
= gimple_call_arg (call
, 0);
2611 if (!POINTER_TYPE_P (TREE_TYPE (lhs
))
2612 || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs
)))
2613 != TYPE_MAIN_VARIANT (cfun_va_list
))
2616 lhs
= build_fold_indirect_ref_loc (loc
, lhs
);
2617 rhs
= build_call_expr_loc (loc
, builtin_decl_explicit (BUILT_IN_NEXT_ARG
),
2618 1, integer_zero_node
);
2619 rhs
= fold_convert_loc (loc
, TREE_TYPE (lhs
), rhs
);
2620 return build2 (MODIFY_EXPR
, TREE_TYPE (lhs
), lhs
, rhs
);
2622 case BUILT_IN_VA_COPY
:
2623 if (!va_list_simple_ptr
)
2626 if (gimple_call_num_args (call
) != 2)
2629 lhs
= gimple_call_arg (call
, 0);
2630 if (!POINTER_TYPE_P (TREE_TYPE (lhs
))
2631 || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs
)))
2632 != TYPE_MAIN_VARIANT (cfun_va_list
))
2635 lhs
= build_fold_indirect_ref_loc (loc
, lhs
);
2636 rhs
= gimple_call_arg (call
, 1);
2637 if (TYPE_MAIN_VARIANT (TREE_TYPE (rhs
))
2638 != TYPE_MAIN_VARIANT (cfun_va_list
))
2641 rhs
= fold_convert_loc (loc
, TREE_TYPE (lhs
), rhs
);
2642 return build2 (MODIFY_EXPR
, TREE_TYPE (lhs
), lhs
, rhs
);
2644 case BUILT_IN_VA_END
:
2645 /* No effect, so the statement will be deleted. */
2646 return integer_zero_node
;
2653 /* Attemp to make the block of __builtin_unreachable I unreachable by changing
2654 the incoming jumps. Return true if at least one jump was changed. */
2657 optimize_unreachable (gimple_stmt_iterator i
)
2659 basic_block bb
= gsi_bb (i
);
2660 gimple_stmt_iterator gsi
;
2666 if (flag_sanitize
& SANITIZE_UNREACHABLE
)
2669 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
2671 stmt
= gsi_stmt (gsi
);
2673 if (is_gimple_debug (stmt
))
2676 if (glabel
*label_stmt
= dyn_cast
<glabel
*> (stmt
))
2678 /* Verify we do not need to preserve the label. */
2679 if (FORCED_LABEL (gimple_label_label (label_stmt
)))
2685 /* Only handle the case that __builtin_unreachable is the first statement
2686 in the block. We rely on DCE to remove stmts without side-effects
2687 before __builtin_unreachable. */
2688 if (gsi_stmt (gsi
) != gsi_stmt (i
))
2693 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
2695 gsi
= gsi_last_bb (e
->src
);
2696 if (gsi_end_p (gsi
))
2699 stmt
= gsi_stmt (gsi
);
2700 if (gcond
*cond_stmt
= dyn_cast
<gcond
*> (stmt
))
2702 if (e
->flags
& EDGE_TRUE_VALUE
)
2703 gimple_cond_make_false (cond_stmt
);
2704 else if (e
->flags
& EDGE_FALSE_VALUE
)
2705 gimple_cond_make_true (cond_stmt
);
2708 update_stmt (cond_stmt
);
2712 /* Todo: handle other cases, f.i. switch statement. */
2723 mask_2 = 1 << cnt_1;
2724 _4 = __atomic_fetch_or_* (ptr_6, mask_2, _3);
2727 _4 = ATOMIC_BIT_TEST_AND_SET (ptr_6, cnt_1, 0, _3);
2729 If _5 is only used in _5 != 0 or _5 == 0 comparisons, 1
2730 is passed instead of 0, and the builtin just returns a zero
2731 or 1 value instead of the actual bit.
2732 Similarly for __sync_fetch_and_or_* (without the ", _3" part
2733 in there), and/or if mask_2 is a power of 2 constant.
2734 Similarly for xor instead of or, use ATOMIC_BIT_TEST_AND_COMPLEMENT
2735 in that case. And similarly for and instead of or, except that
2736 the second argument to the builtin needs to be one's complement
2737 of the mask instead of mask. */
2740 optimize_atomic_bit_test_and (gimple_stmt_iterator
*gsip
,
2741 enum internal_fn fn
, bool has_model_arg
,
2744 gimple
*call
= gsi_stmt (*gsip
);
2745 tree lhs
= gimple_call_lhs (call
);
2746 use_operand_p use_p
;
2751 if (!flag_inline_atomics
2753 || !gimple_call_builtin_p (call
, BUILT_IN_NORMAL
)
2755 || SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs
)
2756 || !single_imm_use (lhs
, &use_p
, &use_stmt
)
2757 || !is_gimple_assign (use_stmt
)
2758 || gimple_assign_rhs_code (use_stmt
) != BIT_AND_EXPR
2759 || !gimple_vdef (call
))
2764 case IFN_ATOMIC_BIT_TEST_AND_SET
:
2765 optab
= atomic_bit_test_and_set_optab
;
2767 case IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT
:
2768 optab
= atomic_bit_test_and_complement_optab
;
2770 case IFN_ATOMIC_BIT_TEST_AND_RESET
:
2771 optab
= atomic_bit_test_and_reset_optab
;
2777 if (optab_handler (optab
, TYPE_MODE (TREE_TYPE (lhs
))) == CODE_FOR_nothing
)
2780 mask
= gimple_call_arg (call
, 1);
2781 tree use_lhs
= gimple_assign_lhs (use_stmt
);
2785 if (TREE_CODE (mask
) == INTEGER_CST
)
2787 if (fn
== IFN_ATOMIC_BIT_TEST_AND_RESET
)
2788 mask
= const_unop (BIT_NOT_EXPR
, TREE_TYPE (mask
), mask
);
2789 mask
= fold_convert (TREE_TYPE (lhs
), mask
);
2790 int ibit
= tree_log2 (mask
);
2793 bit
= build_int_cst (TREE_TYPE (lhs
), ibit
);
2795 else if (TREE_CODE (mask
) == SSA_NAME
)
2797 gimple
*g
= SSA_NAME_DEF_STMT (mask
);
2798 if (fn
== IFN_ATOMIC_BIT_TEST_AND_RESET
)
2800 if (!is_gimple_assign (g
)
2801 || gimple_assign_rhs_code (g
) != BIT_NOT_EXPR
)
2803 mask
= gimple_assign_rhs1 (g
);
2804 if (TREE_CODE (mask
) != SSA_NAME
)
2806 g
= SSA_NAME_DEF_STMT (mask
);
2808 if (!is_gimple_assign (g
)
2809 || gimple_assign_rhs_code (g
) != LSHIFT_EXPR
2810 || !integer_onep (gimple_assign_rhs1 (g
)))
2812 bit
= gimple_assign_rhs2 (g
);
2817 if (gimple_assign_rhs1 (use_stmt
) == lhs
)
2819 if (!operand_equal_p (gimple_assign_rhs2 (use_stmt
), mask
, 0))
2822 else if (gimple_assign_rhs2 (use_stmt
) != lhs
2823 || !operand_equal_p (gimple_assign_rhs1 (use_stmt
), mask
, 0))
2826 bool use_bool
= true;
2827 bool has_debug_uses
= false;
2828 imm_use_iterator iter
;
2831 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (use_lhs
))
2833 FOR_EACH_IMM_USE_STMT (g
, iter
, use_lhs
)
2835 enum tree_code code
= ERROR_MARK
;
2836 tree op0
= NULL_TREE
, op1
= NULL_TREE
;
2837 if (is_gimple_debug (g
))
2839 has_debug_uses
= true;
2842 else if (is_gimple_assign (g
))
2843 switch (gimple_assign_rhs_code (g
))
2846 op1
= gimple_assign_rhs1 (g
);
2847 code
= TREE_CODE (op1
);
2848 op0
= TREE_OPERAND (op1
, 0);
2849 op1
= TREE_OPERAND (op1
, 1);
2853 code
= gimple_assign_rhs_code (g
);
2854 op0
= gimple_assign_rhs1 (g
);
2855 op1
= gimple_assign_rhs2 (g
);
2860 else if (gimple_code (g
) == GIMPLE_COND
)
2862 code
= gimple_cond_code (g
);
2863 op0
= gimple_cond_lhs (g
);
2864 op1
= gimple_cond_rhs (g
);
2867 if ((code
== EQ_EXPR
|| code
== NE_EXPR
)
2869 && integer_zerop (op1
))
2871 use_operand_p use_p
;
2873 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
2880 BREAK_FROM_IMM_USE_STMT (iter
);
2883 tree new_lhs
= make_ssa_name (TREE_TYPE (lhs
));
2884 tree flag
= build_int_cst (TREE_TYPE (lhs
), use_bool
);
2886 g
= gimple_build_call_internal (fn
, 4, gimple_call_arg (call
, 0),
2887 bit
, flag
, gimple_call_arg (call
, 2));
2889 g
= gimple_build_call_internal (fn
, 3, gimple_call_arg (call
, 0),
2891 gimple_call_set_lhs (g
, new_lhs
);
2892 gimple_set_location (g
, gimple_location (call
));
2893 gimple_set_vuse (g
, gimple_vuse (call
));
2894 gimple_set_vdef (g
, gimple_vdef (call
));
2895 bool throws
= stmt_can_throw_internal (call
);
2896 gimple_call_set_nothrow (as_a
<gcall
*> (g
),
2897 gimple_call_nothrow_p (as_a
<gcall
*> (call
)));
2898 SSA_NAME_DEF_STMT (gimple_vdef (call
)) = g
;
2899 gimple_stmt_iterator gsi
= *gsip
;
2900 gsi_insert_after (&gsi
, g
, GSI_NEW_STMT
);
2904 maybe_clean_or_replace_eh_stmt (call
, g
);
2905 if (after
|| (use_bool
&& has_debug_uses
))
2906 e
= find_fallthru_edge (gsi_bb (gsi
)->succs
);
2910 /* The internal function returns the value of the specified bit
2911 before the atomic operation. If we are interested in the value
2912 of the specified bit after the atomic operation (makes only sense
2913 for xor, otherwise the bit content is compile time known),
2914 we need to invert the bit. */
2915 g
= gimple_build_assign (make_ssa_name (TREE_TYPE (lhs
)),
2916 BIT_XOR_EXPR
, new_lhs
,
2917 use_bool
? build_int_cst (TREE_TYPE (lhs
), 1)
2919 new_lhs
= gimple_assign_lhs (g
);
2922 gsi_insert_on_edge_immediate (e
, g
);
2923 gsi
= gsi_for_stmt (g
);
2926 gsi_insert_after (&gsi
, g
, GSI_NEW_STMT
);
2928 if (use_bool
&& has_debug_uses
)
2930 tree temp
= NULL_TREE
;
2931 if (!throws
|| after
|| single_pred_p (e
->dest
))
2933 temp
= make_node (DEBUG_EXPR_DECL
);
2934 DECL_ARTIFICIAL (temp
) = 1;
2935 TREE_TYPE (temp
) = TREE_TYPE (lhs
);
2936 SET_DECL_MODE (temp
, TYPE_MODE (TREE_TYPE (lhs
)));
2937 tree t
= build2 (LSHIFT_EXPR
, TREE_TYPE (lhs
), new_lhs
, bit
);
2938 g
= gimple_build_debug_bind (temp
, t
, g
);
2939 if (throws
&& !after
)
2941 gsi
= gsi_after_labels (e
->dest
);
2942 gsi_insert_before (&gsi
, g
, GSI_SAME_STMT
);
2945 gsi_insert_after (&gsi
, g
, GSI_NEW_STMT
);
2947 FOR_EACH_IMM_USE_STMT (g
, iter
, use_lhs
)
2948 if (is_gimple_debug (g
))
2950 use_operand_p use_p
;
2951 if (temp
== NULL_TREE
)
2952 gimple_debug_bind_reset_value (g
);
2954 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
2955 SET_USE (use_p
, temp
);
2959 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_lhs
)
2960 = SSA_NAME_OCCURS_IN_ABNORMAL_PHI (use_lhs
);
2961 replace_uses_by (use_lhs
, new_lhs
);
2962 gsi
= gsi_for_stmt (use_stmt
);
2963 gsi_remove (&gsi
, true);
2964 release_defs (use_stmt
);
2965 gsi_remove (gsip
, true);
2966 release_ssa_name (lhs
);
2975 Similarly for memset (&a, ..., sizeof (a)); instead of a = {};
2976 and/or memcpy (&b, &a, sizeof (a)); instead of b = a; */
2979 optimize_memcpy (gimple_stmt_iterator
*gsip
, tree dest
, tree src
, tree len
)
2981 gimple
*stmt
= gsi_stmt (*gsip
);
2982 if (gimple_has_volatile_ops (stmt
))
2985 tree vuse
= gimple_vuse (stmt
);
2989 gimple
*defstmt
= SSA_NAME_DEF_STMT (vuse
);
2990 tree src2
= NULL_TREE
, len2
= NULL_TREE
;
2991 HOST_WIDE_INT offset
, offset2
;
2992 tree val
= integer_zero_node
;
2993 if (gimple_store_p (defstmt
)
2994 && gimple_assign_single_p (defstmt
)
2995 && TREE_CODE (gimple_assign_rhs1 (defstmt
)) == CONSTRUCTOR
2996 && !gimple_clobber_p (defstmt
))
2997 src2
= gimple_assign_lhs (defstmt
);
2998 else if (gimple_call_builtin_p (defstmt
, BUILT_IN_MEMSET
)
2999 && TREE_CODE (gimple_call_arg (defstmt
, 0)) == ADDR_EXPR
3000 && TREE_CODE (gimple_call_arg (defstmt
, 1)) == INTEGER_CST
)
3002 src2
= TREE_OPERAND (gimple_call_arg (defstmt
, 0), 0);
3003 len2
= gimple_call_arg (defstmt
, 2);
3004 val
= gimple_call_arg (defstmt
, 1);
3005 /* For non-0 val, we'd have to transform stmt from assignment
3006 into memset (only if dest is addressable). */
3007 if (!integer_zerop (val
) && is_gimple_assign (stmt
))
3011 if (src2
== NULL_TREE
)
3014 if (len
== NULL_TREE
)
3015 len
= (TREE_CODE (src
) == COMPONENT_REF
3016 ? DECL_SIZE_UNIT (TREE_OPERAND (src
, 1))
3017 : TYPE_SIZE_UNIT (TREE_TYPE (src
)));
3018 if (len2
== NULL_TREE
)
3019 len2
= (TREE_CODE (src2
) == COMPONENT_REF
3020 ? DECL_SIZE_UNIT (TREE_OPERAND (src2
, 1))
3021 : TYPE_SIZE_UNIT (TREE_TYPE (src2
)));
3022 if (len
== NULL_TREE
3023 || TREE_CODE (len
) != INTEGER_CST
3024 || len2
== NULL_TREE
3025 || TREE_CODE (len2
) != INTEGER_CST
)
3028 src
= get_addr_base_and_unit_offset (src
, &offset
);
3029 src2
= get_addr_base_and_unit_offset (src2
, &offset2
);
3030 if (src
== NULL_TREE
3031 || src2
== NULL_TREE
3032 || offset
< offset2
)
3035 if (!operand_equal_p (src
, src2
, 0))
3038 /* [ src + offset2, src + offset2 + len2 - 1 ] is set to val.
3040 [ src + offset, src + offset + len - 1 ] is a subset of that. */
3041 if (wi::to_offset (len
) + (offset
- offset2
) > wi::to_offset (len2
))
3044 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3046 fprintf (dump_file
, "Simplified\n ");
3047 print_gimple_stmt (dump_file
, stmt
, 0, dump_flags
);
3048 fprintf (dump_file
, "after previous\n ");
3049 print_gimple_stmt (dump_file
, defstmt
, 0, dump_flags
);
3052 /* For simplicity, don't change the kind of the stmt,
3053 turn dest = src; into dest = {}; and memcpy (&dest, &src, len);
3054 into memset (&dest, val, len);
3055 In theory we could change dest = src into memset if dest
3056 is addressable (maybe beneficial if val is not 0), or
3057 memcpy (&dest, &src, len) into dest = {} if len is the size
3058 of dest, dest isn't volatile. */
3059 if (is_gimple_assign (stmt
))
3061 tree ctor
= build_constructor (TREE_TYPE (dest
), NULL
);
3062 gimple_assign_set_rhs_from_tree (gsip
, ctor
);
3065 else /* If stmt is memcpy, transform it into memset. */
3067 gcall
*call
= as_a
<gcall
*> (stmt
);
3068 tree fndecl
= builtin_decl_implicit (BUILT_IN_MEMSET
);
3069 gimple_call_set_fndecl (call
, fndecl
);
3070 gimple_call_set_fntype (call
, TREE_TYPE (fndecl
));
3071 gimple_call_set_arg (call
, 1, val
);
3075 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3077 fprintf (dump_file
, "into\n ");
3078 print_gimple_stmt (dump_file
, stmt
, 0, dump_flags
);
3082 /* A simple pass that attempts to fold all builtin functions. This pass
3083 is run after we've propagated as many constants as we can. */
3087 const pass_data pass_data_fold_builtins
=
3089 GIMPLE_PASS
, /* type */
3091 OPTGROUP_NONE
, /* optinfo_flags */
3092 TV_NONE
, /* tv_id */
3093 ( PROP_cfg
| PROP_ssa
), /* properties_required */
3094 0, /* properties_provided */
3095 0, /* properties_destroyed */
3096 0, /* todo_flags_start */
3097 TODO_update_ssa
, /* todo_flags_finish */
3100 class pass_fold_builtins
: public gimple_opt_pass
3103 pass_fold_builtins (gcc::context
*ctxt
)
3104 : gimple_opt_pass (pass_data_fold_builtins
, ctxt
)
3107 /* opt_pass methods: */
3108 opt_pass
* clone () { return new pass_fold_builtins (m_ctxt
); }
3109 virtual unsigned int execute (function
*);
3111 }; // class pass_fold_builtins
3114 pass_fold_builtins::execute (function
*fun
)
3116 bool cfg_changed
= false;
3118 unsigned int todoflags
= 0;
3120 FOR_EACH_BB_FN (bb
, fun
)
3122 gimple_stmt_iterator i
;
3123 for (i
= gsi_start_bb (bb
); !gsi_end_p (i
); )
3125 gimple
*stmt
, *old_stmt
;
3127 enum built_in_function fcode
;
3129 stmt
= gsi_stmt (i
);
3131 if (gimple_code (stmt
) != GIMPLE_CALL
)
3133 /* Remove all *ssaname_N ={v} {CLOBBER}; stmts,
3134 after the last GIMPLE DSE they aren't needed and might
3135 unnecessarily keep the SSA_NAMEs live. */
3136 if (gimple_clobber_p (stmt
))
3138 tree lhs
= gimple_assign_lhs (stmt
);
3139 if (TREE_CODE (lhs
) == MEM_REF
3140 && TREE_CODE (TREE_OPERAND (lhs
, 0)) == SSA_NAME
)
3142 unlink_stmt_vdef (stmt
);
3143 gsi_remove (&i
, true);
3144 release_defs (stmt
);
3148 else if (gimple_assign_load_p (stmt
) && gimple_store_p (stmt
))
3149 optimize_memcpy (&i
, gimple_assign_lhs (stmt
),
3150 gimple_assign_rhs1 (stmt
), NULL_TREE
);
3155 callee
= gimple_call_fndecl (stmt
);
3156 if (!callee
|| DECL_BUILT_IN_CLASS (callee
) != BUILT_IN_NORMAL
)
3162 fcode
= DECL_FUNCTION_CODE (callee
);
3167 tree result
= NULL_TREE
;
3168 switch (DECL_FUNCTION_CODE (callee
))
3170 case BUILT_IN_CONSTANT_P
:
3171 /* Resolve __builtin_constant_p. If it hasn't been
3172 folded to integer_one_node by now, it's fairly
3173 certain that the value simply isn't constant. */
3174 result
= integer_zero_node
;
3177 case BUILT_IN_ASSUME_ALIGNED
:
3178 /* Remove __builtin_assume_aligned. */
3179 result
= gimple_call_arg (stmt
, 0);
3182 case BUILT_IN_STACK_RESTORE
:
3183 result
= optimize_stack_restore (i
);
3189 case BUILT_IN_UNREACHABLE
:
3190 if (optimize_unreachable (i
))
3194 case BUILT_IN_ATOMIC_FETCH_OR_1
:
3195 case BUILT_IN_ATOMIC_FETCH_OR_2
:
3196 case BUILT_IN_ATOMIC_FETCH_OR_4
:
3197 case BUILT_IN_ATOMIC_FETCH_OR_8
:
3198 case BUILT_IN_ATOMIC_FETCH_OR_16
:
3199 optimize_atomic_bit_test_and (&i
,
3200 IFN_ATOMIC_BIT_TEST_AND_SET
,
3203 case BUILT_IN_SYNC_FETCH_AND_OR_1
:
3204 case BUILT_IN_SYNC_FETCH_AND_OR_2
:
3205 case BUILT_IN_SYNC_FETCH_AND_OR_4
:
3206 case BUILT_IN_SYNC_FETCH_AND_OR_8
:
3207 case BUILT_IN_SYNC_FETCH_AND_OR_16
:
3208 optimize_atomic_bit_test_and (&i
,
3209 IFN_ATOMIC_BIT_TEST_AND_SET
,
3213 case BUILT_IN_ATOMIC_FETCH_XOR_1
:
3214 case BUILT_IN_ATOMIC_FETCH_XOR_2
:
3215 case BUILT_IN_ATOMIC_FETCH_XOR_4
:
3216 case BUILT_IN_ATOMIC_FETCH_XOR_8
:
3217 case BUILT_IN_ATOMIC_FETCH_XOR_16
:
3218 optimize_atomic_bit_test_and
3219 (&i
, IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT
, true, false);
3221 case BUILT_IN_SYNC_FETCH_AND_XOR_1
:
3222 case BUILT_IN_SYNC_FETCH_AND_XOR_2
:
3223 case BUILT_IN_SYNC_FETCH_AND_XOR_4
:
3224 case BUILT_IN_SYNC_FETCH_AND_XOR_8
:
3225 case BUILT_IN_SYNC_FETCH_AND_XOR_16
:
3226 optimize_atomic_bit_test_and
3227 (&i
, IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT
, false, false);
3230 case BUILT_IN_ATOMIC_XOR_FETCH_1
:
3231 case BUILT_IN_ATOMIC_XOR_FETCH_2
:
3232 case BUILT_IN_ATOMIC_XOR_FETCH_4
:
3233 case BUILT_IN_ATOMIC_XOR_FETCH_8
:
3234 case BUILT_IN_ATOMIC_XOR_FETCH_16
:
3235 optimize_atomic_bit_test_and
3236 (&i
, IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT
, true, true);
3238 case BUILT_IN_SYNC_XOR_AND_FETCH_1
:
3239 case BUILT_IN_SYNC_XOR_AND_FETCH_2
:
3240 case BUILT_IN_SYNC_XOR_AND_FETCH_4
:
3241 case BUILT_IN_SYNC_XOR_AND_FETCH_8
:
3242 case BUILT_IN_SYNC_XOR_AND_FETCH_16
:
3243 optimize_atomic_bit_test_and
3244 (&i
, IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT
, false, true);
3247 case BUILT_IN_ATOMIC_FETCH_AND_1
:
3248 case BUILT_IN_ATOMIC_FETCH_AND_2
:
3249 case BUILT_IN_ATOMIC_FETCH_AND_4
:
3250 case BUILT_IN_ATOMIC_FETCH_AND_8
:
3251 case BUILT_IN_ATOMIC_FETCH_AND_16
:
3252 optimize_atomic_bit_test_and (&i
,
3253 IFN_ATOMIC_BIT_TEST_AND_RESET
,
3256 case BUILT_IN_SYNC_FETCH_AND_AND_1
:
3257 case BUILT_IN_SYNC_FETCH_AND_AND_2
:
3258 case BUILT_IN_SYNC_FETCH_AND_AND_4
:
3259 case BUILT_IN_SYNC_FETCH_AND_AND_8
:
3260 case BUILT_IN_SYNC_FETCH_AND_AND_16
:
3261 optimize_atomic_bit_test_and (&i
,
3262 IFN_ATOMIC_BIT_TEST_AND_RESET
,
3266 case BUILT_IN_MEMCPY
:
3267 if (gimple_call_builtin_p (stmt
, BUILT_IN_NORMAL
)
3268 && TREE_CODE (gimple_call_arg (stmt
, 0)) == ADDR_EXPR
3269 && TREE_CODE (gimple_call_arg (stmt
, 1)) == ADDR_EXPR
3270 && TREE_CODE (gimple_call_arg (stmt
, 2)) == INTEGER_CST
)
3272 tree dest
= TREE_OPERAND (gimple_call_arg (stmt
, 0), 0);
3273 tree src
= TREE_OPERAND (gimple_call_arg (stmt
, 1), 0);
3274 tree len
= gimple_call_arg (stmt
, 2);
3275 optimize_memcpy (&i
, dest
, src
, len
);
3279 case BUILT_IN_VA_START
:
3280 case BUILT_IN_VA_END
:
3281 case BUILT_IN_VA_COPY
:
3282 /* These shouldn't be folded before pass_stdarg. */
3283 result
= optimize_stdarg_builtin (stmt
);
3295 if (!update_call_from_tree (&i
, result
))
3296 gimplify_and_update_call_from_tree (&i
, result
);
3299 todoflags
|= TODO_update_address_taken
;
3301 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3303 fprintf (dump_file
, "Simplified\n ");
3304 print_gimple_stmt (dump_file
, stmt
, 0, dump_flags
);
3308 stmt
= gsi_stmt (i
);
3311 if (maybe_clean_or_replace_eh_stmt (old_stmt
, stmt
)
3312 && gimple_purge_dead_eh_edges (bb
))
3315 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3317 fprintf (dump_file
, "to\n ");
3318 print_gimple_stmt (dump_file
, stmt
, 0, dump_flags
);
3319 fprintf (dump_file
, "\n");
3322 /* Retry the same statement if it changed into another
3323 builtin, there might be new opportunities now. */
3324 if (gimple_code (stmt
) != GIMPLE_CALL
)
3329 callee
= gimple_call_fndecl (stmt
);
3331 || DECL_BUILT_IN_CLASS (callee
) != BUILT_IN_NORMAL
3332 || DECL_FUNCTION_CODE (callee
) == fcode
)
3337 /* Delete unreachable blocks. */
3339 todoflags
|= TODO_cleanup_cfg
;
3347 make_pass_fold_builtins (gcc::context
*ctxt
)
3349 return new pass_fold_builtins (ctxt
);
3352 /* A simple pass that emits some warnings post IPA. */
3356 const pass_data pass_data_post_ipa_warn
=
3358 GIMPLE_PASS
, /* type */
3359 "post_ipa_warn", /* name */
3360 OPTGROUP_NONE
, /* optinfo_flags */
3361 TV_NONE
, /* tv_id */
3362 ( PROP_cfg
| PROP_ssa
), /* properties_required */
3363 0, /* properties_provided */
3364 0, /* properties_destroyed */
3365 0, /* todo_flags_start */
3366 0, /* todo_flags_finish */
3369 class pass_post_ipa_warn
: public gimple_opt_pass
3372 pass_post_ipa_warn (gcc::context
*ctxt
)
3373 : gimple_opt_pass (pass_data_post_ipa_warn
, ctxt
)
3376 /* opt_pass methods: */
3377 opt_pass
* clone () { return new pass_post_ipa_warn (m_ctxt
); }
3378 virtual bool gate (function
*) { return warn_nonnull
!= 0; }
3379 virtual unsigned int execute (function
*);
3381 }; // class pass_fold_builtins
3384 pass_post_ipa_warn::execute (function
*fun
)
3388 FOR_EACH_BB_FN (bb
, fun
)
3390 gimple_stmt_iterator gsi
;
3391 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3393 gimple
*stmt
= gsi_stmt (gsi
);
3394 if (!is_gimple_call (stmt
) || gimple_no_warning_p (stmt
))
3400 = get_nonnull_args (gimple_call_fntype (stmt
));
3403 for (unsigned i
= 0; i
< gimple_call_num_args (stmt
); i
++)
3405 tree arg
= gimple_call_arg (stmt
, i
);
3406 if (TREE_CODE (TREE_TYPE (arg
)) != POINTER_TYPE
)
3408 if (!integer_zerop (arg
))
3410 if (!bitmap_empty_p (nonnullargs
)
3411 && !bitmap_bit_p (nonnullargs
, i
))
3414 location_t loc
= gimple_location (stmt
);
3415 if (warning_at (loc
, OPT_Wnonnull
,
3416 "argument %u null where non-null "
3419 tree fndecl
= gimple_call_fndecl (stmt
);
3420 if (fndecl
&& DECL_IS_BUILTIN (fndecl
))
3421 inform (loc
, "in a call to built-in function %qD",
3424 inform (DECL_SOURCE_LOCATION (fndecl
),
3425 "in a call to function %qD declared here",
3430 BITMAP_FREE (nonnullargs
);
3441 make_pass_post_ipa_warn (gcc::context
*ctxt
)
3443 return new pass_post_ipa_warn (ctxt
);