1 /* Support routines for Value Range Propagation (VRP).
2 Copyright (C) 2005-2020 Free Software Foundation, Inc.
3 Contributed by Diego Novillo <dnovillo@redhat.com>.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
25 #include "insn-codes.h"
30 #include "tree-pass.h"
32 #include "optabs-tree.h"
33 #include "gimple-pretty-print.h"
35 #include "fold-const.h"
36 #include "stor-layout.h"
39 #include "gimple-fold.h"
41 #include "gimple-iterator.h"
42 #include "gimple-walk.h"
44 #include "tree-ssa-loop-manip.h"
45 #include "tree-ssa-loop-niter.h"
46 #include "tree-ssa-loop.h"
47 #include "tree-into-ssa.h"
50 #include "tree-scalar-evolution.h"
51 #include "tree-ssa-propagate.h"
52 #include "tree-chrec.h"
53 #include "tree-ssa-threadupdate.h"
54 #include "tree-ssa-scopedtables.h"
55 #include "tree-ssa-threadedge.h"
56 #include "omp-general.h"
58 #include "case-cfn-macros.h"
59 #include "alloc-pool.h"
61 #include "tree-cfgcleanup.h"
62 #include "stringpool.h"
64 #include "vr-values.h"
67 #include "value-range-equiv.h"
68 #include "gimple-array-bounds.h"
70 /* Set of SSA names found live during the RPO traversal of the function
71 for still active basic-blocks. */
77 void set (tree
, basic_block
);
78 void clear (tree
, basic_block
);
79 void merge (basic_block dest
, basic_block src
);
80 bool live_on_block_p (tree
, basic_block
);
81 bool live_on_edge_p (tree
, edge
);
82 bool block_has_live_names_p (basic_block
);
83 void clear_block (basic_block
);
88 void init_bitmap_if_needed (basic_block
);
92 live_names::init_bitmap_if_needed (basic_block bb
)
94 unsigned i
= bb
->index
;
97 live
[i
] = sbitmap_alloc (num_ssa_names
);
98 bitmap_clear (live
[i
]);
103 live_names::block_has_live_names_p (basic_block bb
)
105 unsigned i
= bb
->index
;
106 return live
[i
] && bitmap_empty_p (live
[i
]);
110 live_names::clear_block (basic_block bb
)
112 unsigned i
= bb
->index
;
115 sbitmap_free (live
[i
]);
121 live_names::merge (basic_block dest
, basic_block src
)
123 init_bitmap_if_needed (dest
);
124 init_bitmap_if_needed (src
);
125 bitmap_ior (live
[dest
->index
], live
[dest
->index
], live
[src
->index
]);
129 live_names::set (tree name
, basic_block bb
)
131 init_bitmap_if_needed (bb
);
132 bitmap_set_bit (live
[bb
->index
], SSA_NAME_VERSION (name
));
136 live_names::clear (tree name
, basic_block bb
)
138 unsigned i
= bb
->index
;
140 bitmap_clear_bit (live
[i
], SSA_NAME_VERSION (name
));
143 live_names::live_names ()
145 num_blocks
= last_basic_block_for_fn (cfun
);
146 live
= XCNEWVEC (sbitmap
, num_blocks
);
149 live_names::~live_names ()
151 for (unsigned i
= 0; i
< num_blocks
; ++i
)
153 sbitmap_free (live
[i
]);
158 live_names::live_on_block_p (tree name
, basic_block bb
)
160 return (live
[bb
->index
]
161 && bitmap_bit_p (live
[bb
->index
], SSA_NAME_VERSION (name
)));
164 /* Return true if the SSA name NAME is live on the edge E. */
167 live_names::live_on_edge_p (tree name
, edge e
)
169 return live_on_block_p (name
, e
->dest
);
173 /* VR_TYPE describes a range with mininum value *MIN and maximum
174 value *MAX. Restrict the range to the set of values that have
175 no bits set outside NONZERO_BITS. Update *MIN and *MAX and
176 return the new range type.
178 SGN gives the sign of the values described by the range. */
180 enum value_range_kind
181 intersect_range_with_nonzero_bits (enum value_range_kind vr_type
,
182 wide_int
*min
, wide_int
*max
,
183 const wide_int
&nonzero_bits
,
186 if (vr_type
== VR_ANTI_RANGE
)
188 /* The VR_ANTI_RANGE is equivalent to the union of the ranges
189 A: [-INF, *MIN) and B: (*MAX, +INF]. First use NONZERO_BITS
190 to create an inclusive upper bound for A and an inclusive lower
192 wide_int a_max
= wi::round_down_for_mask (*min
- 1, nonzero_bits
);
193 wide_int b_min
= wi::round_up_for_mask (*max
+ 1, nonzero_bits
);
195 /* If the calculation of A_MAX wrapped, A is effectively empty
196 and A_MAX is the highest value that satisfies NONZERO_BITS.
197 Likewise if the calculation of B_MIN wrapped, B is effectively
198 empty and B_MIN is the lowest value that satisfies NONZERO_BITS. */
199 bool a_empty
= wi::ge_p (a_max
, *min
, sgn
);
200 bool b_empty
= wi::le_p (b_min
, *max
, sgn
);
202 /* If both A and B are empty, there are no valid values. */
203 if (a_empty
&& b_empty
)
206 /* If exactly one of A or B is empty, return a VR_RANGE for the
208 if (a_empty
|| b_empty
)
212 gcc_checking_assert (wi::le_p (*min
, *max
, sgn
));
216 /* Update the VR_ANTI_RANGE bounds. */
219 gcc_checking_assert (wi::le_p (*min
, *max
, sgn
));
221 /* Now check whether the excluded range includes any values that
222 satisfy NONZERO_BITS. If not, switch to a full VR_RANGE. */
223 if (wi::round_up_for_mask (*min
, nonzero_bits
) == b_min
)
225 unsigned int precision
= min
->get_precision ();
226 *min
= wi::min_value (precision
, sgn
);
227 *max
= wi::max_value (precision
, sgn
);
231 if (vr_type
== VR_RANGE
)
233 *max
= wi::round_down_for_mask (*max
, nonzero_bits
);
235 /* Check that the range contains at least one valid value. */
236 if (wi::gt_p (*min
, *max
, sgn
))
239 *min
= wi::round_up_for_mask (*min
, nonzero_bits
);
240 gcc_checking_assert (wi::le_p (*min
, *max
, sgn
));
245 /* Return true if max and min of VR are INTEGER_CST. It's not necessary
249 range_int_cst_p (const value_range
*vr
)
251 return (vr
->kind () == VR_RANGE
&& range_has_numeric_bounds_p (vr
));
254 /* Return the single symbol (an SSA_NAME) contained in T if any, or NULL_TREE
255 otherwise. We only handle additive operations and set NEG to true if the
256 symbol is negated and INV to the invariant part, if any. */
259 get_single_symbol (tree t
, bool *neg
, tree
*inv
)
267 if (TREE_CODE (t
) == PLUS_EXPR
268 || TREE_CODE (t
) == POINTER_PLUS_EXPR
269 || TREE_CODE (t
) == MINUS_EXPR
)
271 if (is_gimple_min_invariant (TREE_OPERAND (t
, 0)))
273 neg_
= (TREE_CODE (t
) == MINUS_EXPR
);
274 inv_
= TREE_OPERAND (t
, 0);
275 t
= TREE_OPERAND (t
, 1);
277 else if (is_gimple_min_invariant (TREE_OPERAND (t
, 1)))
280 inv_
= TREE_OPERAND (t
, 1);
281 t
= TREE_OPERAND (t
, 0);
292 if (TREE_CODE (t
) == NEGATE_EXPR
)
294 t
= TREE_OPERAND (t
, 0);
298 if (TREE_CODE (t
) != SSA_NAME
)
301 if (inv_
&& TREE_OVERFLOW_P (inv_
))
302 inv_
= drop_tree_overflow (inv_
);
309 /* The reverse operation: build a symbolic expression with TYPE
310 from symbol SYM, negated according to NEG, and invariant INV. */
313 build_symbolic_expr (tree type
, tree sym
, bool neg
, tree inv
)
315 const bool pointer_p
= POINTER_TYPE_P (type
);
319 t
= build1 (NEGATE_EXPR
, type
, t
);
321 if (integer_zerop (inv
))
324 return build2 (pointer_p
? POINTER_PLUS_EXPR
: PLUS_EXPR
, type
, t
, inv
);
330 -2 if those are incomparable. */
332 operand_less_p (tree val
, tree val2
)
334 /* LT is folded faster than GE and others. Inline the common case. */
335 if (TREE_CODE (val
) == INTEGER_CST
&& TREE_CODE (val2
) == INTEGER_CST
)
336 return tree_int_cst_lt (val
, val2
);
337 else if (TREE_CODE (val
) == SSA_NAME
&& TREE_CODE (val2
) == SSA_NAME
)
338 return val
== val2
? 0 : -2;
341 int cmp
= compare_values (val
, val2
);
344 else if (cmp
== 0 || cmp
== 1)
353 /* Compare two values VAL1 and VAL2. Return
355 -2 if VAL1 and VAL2 cannot be compared at compile-time,
358 +1 if VAL1 > VAL2, and
361 This is similar to tree_int_cst_compare but supports pointer values
362 and values that cannot be compared at compile time.
364 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
365 true if the return value is only valid if we assume that signed
366 overflow is undefined. */
369 compare_values_warnv (tree val1
, tree val2
, bool *strict_overflow_p
)
374 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
376 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1
))
377 == POINTER_TYPE_P (TREE_TYPE (val2
)));
379 /* Convert the two values into the same type. This is needed because
380 sizetype causes sign extension even for unsigned types. */
381 if (!useless_type_conversion_p (TREE_TYPE (val1
), TREE_TYPE (val2
)))
382 val2
= fold_convert (TREE_TYPE (val1
), val2
);
384 const bool overflow_undefined
385 = INTEGRAL_TYPE_P (TREE_TYPE (val1
))
386 && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1
));
389 tree sym1
= get_single_symbol (val1
, &neg1
, &inv1
);
390 tree sym2
= get_single_symbol (val2
, &neg2
, &inv2
);
392 /* If VAL1 and VAL2 are of the form '[-]NAME [+ CST]', return -1 or +1
393 accordingly. If VAL1 and VAL2 don't use the same name, return -2. */
396 /* Both values must use the same name with the same sign. */
397 if (sym1
!= sym2
|| neg1
!= neg2
)
400 /* [-]NAME + CST == [-]NAME + CST. */
404 /* If overflow is defined we cannot simplify more. */
405 if (!overflow_undefined
)
408 if (strict_overflow_p
!= NULL
409 /* Symbolic range building sets TREE_NO_WARNING to declare
410 that overflow doesn't happen. */
411 && (!inv1
|| !TREE_NO_WARNING (val1
))
412 && (!inv2
|| !TREE_NO_WARNING (val2
)))
413 *strict_overflow_p
= true;
416 inv1
= build_int_cst (TREE_TYPE (val1
), 0);
418 inv2
= build_int_cst (TREE_TYPE (val2
), 0);
420 return wi::cmp (wi::to_wide (inv1
), wi::to_wide (inv2
),
421 TYPE_SIGN (TREE_TYPE (val1
)));
424 const bool cst1
= is_gimple_min_invariant (val1
);
425 const bool cst2
= is_gimple_min_invariant (val2
);
427 /* If one is of the form '[-]NAME + CST' and the other is constant, then
428 it might be possible to say something depending on the constants. */
429 if ((sym1
&& inv1
&& cst2
) || (sym2
&& inv2
&& cst1
))
431 if (!overflow_undefined
)
434 if (strict_overflow_p
!= NULL
435 /* Symbolic range building sets TREE_NO_WARNING to declare
436 that overflow doesn't happen. */
437 && (!sym1
|| !TREE_NO_WARNING (val1
))
438 && (!sym2
|| !TREE_NO_WARNING (val2
)))
439 *strict_overflow_p
= true;
441 const signop sgn
= TYPE_SIGN (TREE_TYPE (val1
));
442 tree cst
= cst1
? val1
: val2
;
443 tree inv
= cst1
? inv2
: inv1
;
445 /* Compute the difference between the constants. If it overflows or
446 underflows, this means that we can trivially compare the NAME with
447 it and, consequently, the two values with each other. */
448 wide_int diff
= wi::to_wide (cst
) - wi::to_wide (inv
);
449 if (wi::cmp (0, wi::to_wide (inv
), sgn
)
450 != wi::cmp (diff
, wi::to_wide (cst
), sgn
))
452 const int res
= wi::cmp (wi::to_wide (cst
), wi::to_wide (inv
), sgn
);
453 return cst1
? res
: -res
;
459 /* We cannot say anything more for non-constants. */
463 if (!POINTER_TYPE_P (TREE_TYPE (val1
)))
465 /* We cannot compare overflowed values. */
466 if (TREE_OVERFLOW (val1
) || TREE_OVERFLOW (val2
))
469 if (TREE_CODE (val1
) == INTEGER_CST
470 && TREE_CODE (val2
) == INTEGER_CST
)
471 return tree_int_cst_compare (val1
, val2
);
473 if (poly_int_tree_p (val1
) && poly_int_tree_p (val2
))
475 if (known_eq (wi::to_poly_widest (val1
),
476 wi::to_poly_widest (val2
)))
478 if (known_lt (wi::to_poly_widest (val1
),
479 wi::to_poly_widest (val2
)))
481 if (known_gt (wi::to_poly_widest (val1
),
482 wi::to_poly_widest (val2
)))
490 if (TREE_CODE (val1
) == INTEGER_CST
&& TREE_CODE (val2
) == INTEGER_CST
)
492 /* We cannot compare overflowed values. */
493 if (TREE_OVERFLOW (val1
) || TREE_OVERFLOW (val2
))
496 return tree_int_cst_compare (val1
, val2
);
499 /* First see if VAL1 and VAL2 are not the same. */
500 if (operand_equal_p (val1
, val2
, 0))
503 fold_defer_overflow_warnings ();
505 /* If VAL1 is a lower address than VAL2, return -1. */
506 tree t
= fold_binary_to_constant (LT_EXPR
, boolean_type_node
, val1
, val2
);
507 if (t
&& integer_onep (t
))
509 fold_undefer_and_ignore_overflow_warnings ();
513 /* If VAL1 is a higher address than VAL2, return +1. */
514 t
= fold_binary_to_constant (LT_EXPR
, boolean_type_node
, val2
, val1
);
515 if (t
&& integer_onep (t
))
517 fold_undefer_and_ignore_overflow_warnings ();
521 /* If VAL1 is different than VAL2, return +2. */
522 t
= fold_binary_to_constant (NE_EXPR
, boolean_type_node
, val1
, val2
);
523 fold_undefer_and_ignore_overflow_warnings ();
524 if (t
&& integer_onep (t
))
531 /* Compare values like compare_values_warnv. */
534 compare_values (tree val1
, tree val2
)
537 return compare_values_warnv (val1
, val2
, &sop
);
540 /* If BOUND will include a symbolic bound, adjust it accordingly,
541 otherwise leave it as is.
543 CODE is the original operation that combined the bounds (PLUS_EXPR
546 TYPE is the type of the original operation.
548 SYM_OPn is the symbolic for OPn if it has a symbolic.
550 NEG_OPn is TRUE if the OPn was negated. */
553 adjust_symbolic_bound (tree
&bound
, enum tree_code code
, tree type
,
554 tree sym_op0
, tree sym_op1
,
555 bool neg_op0
, bool neg_op1
)
557 bool minus_p
= (code
== MINUS_EXPR
);
558 /* If the result bound is constant, we're done; otherwise, build the
559 symbolic lower bound. */
560 if (sym_op0
== sym_op1
)
563 bound
= build_symbolic_expr (type
, sym_op0
,
567 /* We may not negate if that might introduce
568 undefined overflow. */
571 || TYPE_OVERFLOW_WRAPS (type
))
572 bound
= build_symbolic_expr (type
, sym_op1
,
573 neg_op1
^ minus_p
, bound
);
579 /* Combine OP1 and OP1, which are two parts of a bound, into one wide
580 int bound according to CODE. CODE is the operation combining the
581 bound (either a PLUS_EXPR or a MINUS_EXPR).
583 TYPE is the type of the combine operation.
585 WI is the wide int to store the result.
587 OVF is -1 if an underflow occurred, +1 if an overflow occurred or 0
588 if over/underflow occurred. */
591 combine_bound (enum tree_code code
, wide_int
&wi
, wi::overflow_type
&ovf
,
592 tree type
, tree op0
, tree op1
)
594 bool minus_p
= (code
== MINUS_EXPR
);
595 const signop sgn
= TYPE_SIGN (type
);
596 const unsigned int prec
= TYPE_PRECISION (type
);
598 /* Combine the bounds, if any. */
602 wi
= wi::sub (wi::to_wide (op0
), wi::to_wide (op1
), sgn
, &ovf
);
604 wi
= wi::add (wi::to_wide (op0
), wi::to_wide (op1
), sgn
, &ovf
);
607 wi
= wi::to_wide (op0
);
611 wi
= wi::neg (wi::to_wide (op1
), &ovf
);
613 wi
= wi::to_wide (op1
);
616 wi
= wi::shwi (0, prec
);
619 /* Given a range in [WMIN, WMAX], adjust it for possible overflow and
620 put the result in VR.
622 TYPE is the type of the range.
624 MIN_OVF and MAX_OVF indicate what type of overflow, if any,
625 occurred while originally calculating WMIN or WMAX. -1 indicates
626 underflow. +1 indicates overflow. 0 indicates neither. */
629 set_value_range_with_overflow (value_range_kind
&kind
, tree
&min
, tree
&max
,
631 const wide_int
&wmin
, const wide_int
&wmax
,
632 wi::overflow_type min_ovf
,
633 wi::overflow_type max_ovf
)
635 const signop sgn
= TYPE_SIGN (type
);
636 const unsigned int prec
= TYPE_PRECISION (type
);
638 /* For one bit precision if max < min, then the swapped
639 range covers all values. */
640 if (prec
== 1 && wi::lt_p (wmax
, wmin
, sgn
))
646 if (TYPE_OVERFLOW_WRAPS (type
))
648 /* If overflow wraps, truncate the values and adjust the
649 range kind and bounds appropriately. */
650 wide_int tmin
= wide_int::from (wmin
, prec
, sgn
);
651 wide_int tmax
= wide_int::from (wmax
, prec
, sgn
);
652 if ((min_ovf
!= wi::OVF_NONE
) == (max_ovf
!= wi::OVF_NONE
))
654 /* If the limits are swapped, we wrapped around and cover
656 if (wi::gt_p (tmin
, tmax
, sgn
))
661 /* No overflow or both overflow or underflow. The
662 range kind stays VR_RANGE. */
663 min
= wide_int_to_tree (type
, tmin
);
664 max
= wide_int_to_tree (type
, tmax
);
668 else if ((min_ovf
== wi::OVF_UNDERFLOW
&& max_ovf
== wi::OVF_NONE
)
669 || (max_ovf
== wi::OVF_OVERFLOW
&& min_ovf
== wi::OVF_NONE
))
671 /* Min underflow or max overflow. The range kind
672 changes to VR_ANTI_RANGE. */
676 if (wi::cmp (tmin
, tmax
, sgn
) < 0)
679 if (wi::cmp (tmax
, tem
, sgn
) > 0)
681 /* If the anti-range would cover nothing, drop to varying.
682 Likewise if the anti-range bounds are outside of the
684 if (covers
|| wi::cmp (tmin
, tmax
, sgn
) > 0)
689 kind
= VR_ANTI_RANGE
;
690 min
= wide_int_to_tree (type
, tmin
);
691 max
= wide_int_to_tree (type
, tmax
);
696 /* Other underflow and/or overflow, drop to VR_VARYING. */
703 /* If overflow does not wrap, saturate to the types min/max
705 wide_int type_min
= wi::min_value (prec
, sgn
);
706 wide_int type_max
= wi::max_value (prec
, sgn
);
708 if (min_ovf
== wi::OVF_UNDERFLOW
)
709 min
= wide_int_to_tree (type
, type_min
);
710 else if (min_ovf
== wi::OVF_OVERFLOW
)
711 min
= wide_int_to_tree (type
, type_max
);
713 min
= wide_int_to_tree (type
, wmin
);
715 if (max_ovf
== wi::OVF_UNDERFLOW
)
716 max
= wide_int_to_tree (type
, type_min
);
717 else if (max_ovf
== wi::OVF_OVERFLOW
)
718 max
= wide_int_to_tree (type
, type_max
);
720 max
= wide_int_to_tree (type
, wmax
);
724 /* Fold two value range's of a POINTER_PLUS_EXPR into VR. */
727 extract_range_from_pointer_plus_expr (value_range
*vr
,
730 const value_range
*vr0
,
731 const value_range
*vr1
)
733 gcc_checking_assert (POINTER_TYPE_P (expr_type
)
734 && code
== POINTER_PLUS_EXPR
);
735 /* For pointer types, we are really only interested in asserting
736 whether the expression evaluates to non-NULL.
737 With -fno-delete-null-pointer-checks we need to be more
738 conservative. As some object might reside at address 0,
739 then some offset could be added to it and the same offset
740 subtracted again and the result would be NULL.
742 static int a[12]; where &a[0] is NULL and
745 ptr will be NULL here, even when there is POINTER_PLUS_EXPR
746 where the first range doesn't include zero and the second one
747 doesn't either. As the second operand is sizetype (unsigned),
748 consider all ranges where the MSB could be set as possible
749 subtractions where the result might be NULL. */
750 if ((!range_includes_zero_p (vr0
)
751 || !range_includes_zero_p (vr1
))
752 && !TYPE_OVERFLOW_WRAPS (expr_type
)
753 && (flag_delete_null_pointer_checks
754 || (range_int_cst_p (vr1
)
755 && !tree_int_cst_sign_bit (vr1
->max ()))))
756 vr
->set_nonzero (expr_type
);
757 else if (vr0
->zero_p () && vr1
->zero_p ())
758 vr
->set_zero (expr_type
);
760 vr
->set_varying (expr_type
);
763 /* Extract range information from a PLUS/MINUS_EXPR and store the
767 extract_range_from_plus_minus_expr (value_range
*vr
,
770 const value_range
*vr0_
,
771 const value_range
*vr1_
)
773 gcc_checking_assert (code
== PLUS_EXPR
|| code
== MINUS_EXPR
);
775 value_range vr0
= *vr0_
, vr1
= *vr1_
;
776 value_range vrtem0
, vrtem1
;
778 /* Now canonicalize anti-ranges to ranges when they are not symbolic
779 and express ~[] op X as ([]' op X) U ([]'' op X). */
780 if (vr0
.kind () == VR_ANTI_RANGE
781 && ranges_from_anti_range (&vr0
, &vrtem0
, &vrtem1
))
783 extract_range_from_plus_minus_expr (vr
, code
, expr_type
, &vrtem0
, vr1_
);
784 if (!vrtem1
.undefined_p ())
787 extract_range_from_plus_minus_expr (&vrres
, code
, expr_type
,
793 /* Likewise for X op ~[]. */
794 if (vr1
.kind () == VR_ANTI_RANGE
795 && ranges_from_anti_range (&vr1
, &vrtem0
, &vrtem1
))
797 extract_range_from_plus_minus_expr (vr
, code
, expr_type
, vr0_
, &vrtem0
);
798 if (!vrtem1
.undefined_p ())
801 extract_range_from_plus_minus_expr (&vrres
, code
, expr_type
,
808 value_range_kind kind
;
809 value_range_kind vr0_kind
= vr0
.kind (), vr1_kind
= vr1
.kind ();
810 tree vr0_min
= vr0
.min (), vr0_max
= vr0
.max ();
811 tree vr1_min
= vr1
.min (), vr1_max
= vr1
.max ();
812 tree min
= NULL_TREE
, max
= NULL_TREE
;
814 /* This will normalize things such that calculating
815 [0,0] - VR_VARYING is not dropped to varying, but is
816 calculated as [MIN+1, MAX]. */
817 if (vr0
.varying_p ())
820 vr0_min
= vrp_val_min (expr_type
);
821 vr0_max
= vrp_val_max (expr_type
);
823 if (vr1
.varying_p ())
826 vr1_min
= vrp_val_min (expr_type
);
827 vr1_max
= vrp_val_max (expr_type
);
830 const bool minus_p
= (code
== MINUS_EXPR
);
831 tree min_op0
= vr0_min
;
832 tree min_op1
= minus_p
? vr1_max
: vr1_min
;
833 tree max_op0
= vr0_max
;
834 tree max_op1
= minus_p
? vr1_min
: vr1_max
;
835 tree sym_min_op0
= NULL_TREE
;
836 tree sym_min_op1
= NULL_TREE
;
837 tree sym_max_op0
= NULL_TREE
;
838 tree sym_max_op1
= NULL_TREE
;
839 bool neg_min_op0
, neg_min_op1
, neg_max_op0
, neg_max_op1
;
841 neg_min_op0
= neg_min_op1
= neg_max_op0
= neg_max_op1
= false;
843 /* If we have a PLUS or MINUS with two VR_RANGEs, either constant or
844 single-symbolic ranges, try to compute the precise resulting range,
845 but only if we know that this resulting range will also be constant
846 or single-symbolic. */
847 if (vr0_kind
== VR_RANGE
&& vr1_kind
== VR_RANGE
848 && (TREE_CODE (min_op0
) == INTEGER_CST
850 = get_single_symbol (min_op0
, &neg_min_op0
, &min_op0
)))
851 && (TREE_CODE (min_op1
) == INTEGER_CST
853 = get_single_symbol (min_op1
, &neg_min_op1
, &min_op1
)))
854 && (!(sym_min_op0
&& sym_min_op1
)
855 || (sym_min_op0
== sym_min_op1
856 && neg_min_op0
== (minus_p
? neg_min_op1
: !neg_min_op1
)))
857 && (TREE_CODE (max_op0
) == INTEGER_CST
859 = get_single_symbol (max_op0
, &neg_max_op0
, &max_op0
)))
860 && (TREE_CODE (max_op1
) == INTEGER_CST
862 = get_single_symbol (max_op1
, &neg_max_op1
, &max_op1
)))
863 && (!(sym_max_op0
&& sym_max_op1
)
864 || (sym_max_op0
== sym_max_op1
865 && neg_max_op0
== (minus_p
? neg_max_op1
: !neg_max_op1
))))
868 wi::overflow_type min_ovf
= wi::OVF_NONE
;
869 wi::overflow_type max_ovf
= wi::OVF_NONE
;
871 /* Build the bounds. */
872 combine_bound (code
, wmin
, min_ovf
, expr_type
, min_op0
, min_op1
);
873 combine_bound (code
, wmax
, max_ovf
, expr_type
, max_op0
, max_op1
);
875 /* If the resulting range will be symbolic, we need to eliminate any
876 explicit or implicit overflow introduced in the above computation
877 because compare_values could make an incorrect use of it. That's
878 why we require one of the ranges to be a singleton. */
879 if ((sym_min_op0
!= sym_min_op1
|| sym_max_op0
!= sym_max_op1
)
880 && ((bool)min_ovf
|| (bool)max_ovf
881 || (min_op0
!= max_op0
&& min_op1
!= max_op1
)))
883 vr
->set_varying (expr_type
);
887 /* Adjust the range for possible overflow. */
888 set_value_range_with_overflow (kind
, min
, max
, expr_type
,
889 wmin
, wmax
, min_ovf
, max_ovf
);
890 if (kind
== VR_VARYING
)
892 vr
->set_varying (expr_type
);
896 /* Build the symbolic bounds if needed. */
897 adjust_symbolic_bound (min
, code
, expr_type
,
898 sym_min_op0
, sym_min_op1
,
899 neg_min_op0
, neg_min_op1
);
900 adjust_symbolic_bound (max
, code
, expr_type
,
901 sym_max_op0
, sym_max_op1
,
902 neg_max_op0
, neg_max_op1
);
906 /* For other cases, for example if we have a PLUS_EXPR with two
907 VR_ANTI_RANGEs, drop to VR_VARYING. It would take more effort
908 to compute a precise range for such a case.
909 ??? General even mixed range kind operations can be expressed
910 by for example transforming ~[3, 5] + [1, 2] to range-only
911 operations and a union primitive:
912 [-INF, 2] + [1, 2] U [5, +INF] + [1, 2]
913 [-INF+1, 4] U [6, +INF(OVF)]
914 though usually the union is not exactly representable with
915 a single range or anti-range as the above is
916 [-INF+1, +INF(OVF)] intersected with ~[5, 5]
917 but one could use a scheme similar to equivalences for this. */
918 vr
->set_varying (expr_type
);
922 /* If either MIN or MAX overflowed, then set the resulting range to
925 || TREE_OVERFLOW_P (min
)
927 || TREE_OVERFLOW_P (max
))
929 vr
->set_varying (expr_type
);
933 int cmp
= compare_values (min
, max
);
934 if (cmp
== -2 || cmp
== 1)
936 /* If the new range has its limits swapped around (MIN > MAX),
937 then the operation caused one of them to wrap around, mark
938 the new range VARYING. */
939 vr
->set_varying (expr_type
);
942 vr
->set (min
, max
, kind
);
945 /* Return the range-ops handler for CODE and EXPR_TYPE. If no
946 suitable operator is found, return NULL and set VR to VARYING. */
948 static const range_operator
*
949 get_range_op_handler (value_range
*vr
,
953 const range_operator
*op
= range_op_handler (code
, expr_type
);
955 vr
->set_varying (expr_type
);
959 /* If the types passed are supported, return TRUE, otherwise set VR to
960 VARYING and return FALSE. */
963 supported_types_p (value_range
*vr
,
967 if (!value_range::supports_type_p (type0
)
968 || (type1
&& !value_range::supports_type_p (type1
)))
970 vr
->set_varying (type0
);
976 /* If any of the ranges passed are defined, return TRUE, otherwise set
977 VR to UNDEFINED and return FALSE. */
980 defined_ranges_p (value_range
*vr
,
981 const value_range
*vr0
, const value_range
*vr1
= NULL
)
983 if (vr0
->undefined_p () && (!vr1
|| vr1
->undefined_p ()))
985 vr
->set_undefined ();
992 drop_undefines_to_varying (const value_range
*vr
, tree expr_type
)
994 if (vr
->undefined_p ())
995 return value_range (expr_type
);
1000 /* If any operand is symbolic, perform a binary operation on them and
1001 return TRUE, otherwise return FALSE. */
1004 range_fold_binary_symbolics_p (value_range
*vr
,
1007 const value_range
*vr0_
,
1008 const value_range
*vr1_
)
1010 if (vr0_
->symbolic_p () || vr1_
->symbolic_p ())
1012 value_range vr0
= drop_undefines_to_varying (vr0_
, expr_type
);
1013 value_range vr1
= drop_undefines_to_varying (vr1_
, expr_type
);
1014 if ((code
== PLUS_EXPR
|| code
== MINUS_EXPR
))
1016 extract_range_from_plus_minus_expr (vr
, code
, expr_type
,
1020 if (POINTER_TYPE_P (expr_type
) && code
== POINTER_PLUS_EXPR
)
1022 extract_range_from_pointer_plus_expr (vr
, code
, expr_type
,
1026 const range_operator
*op
= get_range_op_handler (vr
, code
, expr_type
);
1027 vr0
.normalize_symbolics ();
1028 vr1
.normalize_symbolics ();
1029 return op
->fold_range (*vr
, expr_type
, vr0
, vr1
);
1034 /* If operand is symbolic, perform a unary operation on it and return
1035 TRUE, otherwise return FALSE. */
1038 range_fold_unary_symbolics_p (value_range
*vr
,
1041 const value_range
*vr0
)
1043 if (vr0
->symbolic_p ())
1045 if (code
== NEGATE_EXPR
)
1047 /* -X is simply 0 - X. */
1049 zero
.set_zero (vr0
->type ());
1050 range_fold_binary_expr (vr
, MINUS_EXPR
, expr_type
, &zero
, vr0
);
1053 if (code
== BIT_NOT_EXPR
)
1055 /* ~X is simply -1 - X. */
1056 value_range minusone
;
1057 minusone
.set (build_int_cst (vr0
->type (), -1));
1058 range_fold_binary_expr (vr
, MINUS_EXPR
, expr_type
, &minusone
, vr0
);
1061 const range_operator
*op
= get_range_op_handler (vr
, code
, expr_type
);
1062 value_range
vr0_cst (*vr0
);
1063 vr0_cst
.normalize_symbolics ();
1064 return op
->fold_range (*vr
, expr_type
, vr0_cst
, value_range (expr_type
));
1069 /* Perform a binary operation on a pair of ranges. */
1072 range_fold_binary_expr (value_range
*vr
,
1073 enum tree_code code
,
1075 const value_range
*vr0_
,
1076 const value_range
*vr1_
)
1078 if (!supported_types_p (vr
, expr_type
)
1079 || !defined_ranges_p (vr
, vr0_
, vr1_
))
1081 const range_operator
*op
= get_range_op_handler (vr
, code
, expr_type
);
1085 if (range_fold_binary_symbolics_p (vr
, code
, expr_type
, vr0_
, vr1_
))
1088 value_range
vr0 (*vr0_
);
1089 value_range
vr1 (*vr1_
);
1090 if (vr0
.undefined_p ())
1091 vr0
.set_varying (expr_type
);
1092 if (vr1
.undefined_p ())
1093 vr1
.set_varying (expr_type
);
1094 vr0
.normalize_addresses ();
1095 vr1
.normalize_addresses ();
1096 op
->fold_range (*vr
, expr_type
, vr0
, vr1
);
1099 /* Perform a unary operation on a range. */
1102 range_fold_unary_expr (value_range
*vr
,
1103 enum tree_code code
, tree expr_type
,
1104 const value_range
*vr0
,
1107 if (!supported_types_p (vr
, expr_type
, vr0_type
)
1108 || !defined_ranges_p (vr
, vr0
))
1110 const range_operator
*op
= get_range_op_handler (vr
, code
, expr_type
);
1114 if (range_fold_unary_symbolics_p (vr
, code
, expr_type
, vr0
))
1117 value_range
vr0_cst (*vr0
);
1118 vr0_cst
.normalize_addresses ();
1119 op
->fold_range (*vr
, expr_type
, vr0_cst
, value_range (expr_type
));
1122 /* If the range of values taken by OP can be inferred after STMT executes,
1123 return the comparison code (COMP_CODE_P) and value (VAL_P) that
1124 describes the inferred range. Return true if a range could be
1128 infer_value_range (gimple
*stmt
, tree op
, tree_code
*comp_code_p
, tree
*val_p
)
1131 *comp_code_p
= ERROR_MARK
;
1133 /* Do not attempt to infer anything in names that flow through
1135 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op
))
1138 /* If STMT is the last statement of a basic block with no normal
1139 successors, there is no point inferring anything about any of its
1140 operands. We would not be able to find a proper insertion point
1141 for the assertion, anyway. */
1142 if (stmt_ends_bb_p (stmt
))
1147 FOR_EACH_EDGE (e
, ei
, gimple_bb (stmt
)->succs
)
1148 if (!(e
->flags
& (EDGE_ABNORMAL
|EDGE_EH
)))
1154 if (infer_nonnull_range (stmt
, op
))
1156 *val_p
= build_int_cst (TREE_TYPE (op
), 0);
1157 *comp_code_p
= NE_EXPR
;
1164 /* Dump assert_info structure. */
1167 dump_assert_info (FILE *file
, const assert_info
&assert)
1169 fprintf (file
, "Assert for: ");
1170 print_generic_expr (file
, assert.name
);
1171 fprintf (file
, "\n\tPREDICATE: expr=[");
1172 print_generic_expr (file
, assert.expr
);
1173 fprintf (file
, "] %s ", get_tree_code_name (assert.comp_code
));
1174 fprintf (file
, "val=[");
1175 print_generic_expr (file
, assert.val
);
1176 fprintf (file
, "]\n\n");
1180 debug (const assert_info
&assert)
1182 dump_assert_info (stderr
, assert);
1185 /* Dump a vector of assert_info's. */
1188 dump_asserts_info (FILE *file
, const vec
<assert_info
> &asserts
)
1190 for (unsigned i
= 0; i
< asserts
.length (); ++i
)
1192 dump_assert_info (file
, asserts
[i
]);
1193 fprintf (file
, "\n");
1198 debug (const vec
<assert_info
> &asserts
)
1200 dump_asserts_info (stderr
, asserts
);
1203 /* Push the assert info for NAME, EXPR, COMP_CODE and VAL to ASSERTS. */
1206 add_assert_info (vec
<assert_info
> &asserts
,
1207 tree name
, tree expr
, enum tree_code comp_code
, tree val
)
1210 info
.comp_code
= comp_code
;
1212 if (TREE_OVERFLOW_P (val
))
1213 val
= drop_tree_overflow (val
);
1216 asserts
.safe_push (info
);
1217 if (dump_enabled_p ())
1218 dump_printf (MSG_NOTE
| MSG_PRIORITY_INTERNALS
,
1219 "Adding assert for %T from %T %s %T\n",
1220 name
, expr
, op_symbol_code (comp_code
), val
);
1223 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
1224 Extract a suitable test code and value and store them into *CODE_P and
1225 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
1227 If no extraction was possible, return FALSE, otherwise return TRUE.
1229 If INVERT is true, then we invert the result stored into *CODE_P. */
1232 extract_code_and_val_from_cond_with_ops (tree name
, enum tree_code cond_code
,
1233 tree cond_op0
, tree cond_op1
,
1234 bool invert
, enum tree_code
*code_p
,
1237 enum tree_code comp_code
;
1240 /* Otherwise, we have a comparison of the form NAME COMP VAL
1241 or VAL COMP NAME. */
1242 if (name
== cond_op1
)
1244 /* If the predicate is of the form VAL COMP NAME, flip
1245 COMP around because we need to register NAME as the
1246 first operand in the predicate. */
1247 comp_code
= swap_tree_comparison (cond_code
);
1250 else if (name
== cond_op0
)
1252 /* The comparison is of the form NAME COMP VAL, so the
1253 comparison code remains unchanged. */
1254 comp_code
= cond_code
;
1260 /* Invert the comparison code as necessary. */
1262 comp_code
= invert_tree_comparison (comp_code
, 0);
1264 /* VRP only handles integral and pointer types. */
1265 if (! INTEGRAL_TYPE_P (TREE_TYPE (val
))
1266 && ! POINTER_TYPE_P (TREE_TYPE (val
)))
1269 /* Do not register always-false predicates.
1270 FIXME: this works around a limitation in fold() when dealing with
1271 enumerations. Given 'enum { N1, N2 } x;', fold will not
1272 fold 'if (x > N2)' to 'if (0)'. */
1273 if ((comp_code
== GT_EXPR
|| comp_code
== LT_EXPR
)
1274 && INTEGRAL_TYPE_P (TREE_TYPE (val
)))
1276 tree min
= TYPE_MIN_VALUE (TREE_TYPE (val
));
1277 tree max
= TYPE_MAX_VALUE (TREE_TYPE (val
));
1279 if (comp_code
== GT_EXPR
1281 || compare_values (val
, max
) == 0))
1284 if (comp_code
== LT_EXPR
1286 || compare_values (val
, min
) == 0))
1289 *code_p
= comp_code
;
1294 /* Find out smallest RES where RES > VAL && (RES & MASK) == RES, if any
1295 (otherwise return VAL). VAL and MASK must be zero-extended for
1296 precision PREC. If SGNBIT is non-zero, first xor VAL with SGNBIT
1297 (to transform signed values into unsigned) and at the end xor
1301 masked_increment (const wide_int
&val_in
, const wide_int
&mask
,
1302 const wide_int
&sgnbit
, unsigned int prec
)
1304 wide_int bit
= wi::one (prec
), res
;
1307 wide_int val
= val_in
^ sgnbit
;
1308 for (i
= 0; i
< prec
; i
++, bit
+= bit
)
1311 if ((res
& bit
) == 0)
1314 res
= wi::bit_and_not (val
+ bit
, res
);
1316 if (wi::gtu_p (res
, val
))
1317 return res
^ sgnbit
;
1319 return val
^ sgnbit
;
1322 /* Helper for overflow_comparison_p
1324 OP0 CODE OP1 is a comparison. Examine the comparison and potentially
1325 OP1's defining statement to see if it ultimately has the form
1326 OP0 CODE (OP0 PLUS INTEGER_CST)
1328 If so, return TRUE indicating this is an overflow test and store into
1329 *NEW_CST an updated constant that can be used in a narrowed range test.
1331 REVERSED indicates if the comparison was originally:
1335 This affects how we build the updated constant. */
1338 overflow_comparison_p_1 (enum tree_code code
, tree op0
, tree op1
,
1339 bool follow_assert_exprs
, bool reversed
, tree
*new_cst
)
1341 /* See if this is a relational operation between two SSA_NAMES with
1342 unsigned, overflow wrapping values. If so, check it more deeply. */
1343 if ((code
== LT_EXPR
|| code
== LE_EXPR
1344 || code
== GE_EXPR
|| code
== GT_EXPR
)
1345 && TREE_CODE (op0
) == SSA_NAME
1346 && TREE_CODE (op1
) == SSA_NAME
1347 && INTEGRAL_TYPE_P (TREE_TYPE (op0
))
1348 && TYPE_UNSIGNED (TREE_TYPE (op0
))
1349 && TYPE_OVERFLOW_WRAPS (TREE_TYPE (op0
)))
1351 gimple
*op1_def
= SSA_NAME_DEF_STMT (op1
);
1353 /* If requested, follow any ASSERT_EXPRs backwards for OP1. */
1354 if (follow_assert_exprs
)
1356 while (gimple_assign_single_p (op1_def
)
1357 && TREE_CODE (gimple_assign_rhs1 (op1_def
)) == ASSERT_EXPR
)
1359 op1
= TREE_OPERAND (gimple_assign_rhs1 (op1_def
), 0);
1360 if (TREE_CODE (op1
) != SSA_NAME
)
1362 op1_def
= SSA_NAME_DEF_STMT (op1
);
1366 /* Now look at the defining statement of OP1 to see if it adds
1367 or subtracts a nonzero constant from another operand. */
1369 && is_gimple_assign (op1_def
)
1370 && gimple_assign_rhs_code (op1_def
) == PLUS_EXPR
1371 && TREE_CODE (gimple_assign_rhs2 (op1_def
)) == INTEGER_CST
1372 && !integer_zerop (gimple_assign_rhs2 (op1_def
)))
1374 tree target
= gimple_assign_rhs1 (op1_def
);
1376 /* If requested, follow ASSERT_EXPRs backwards for op0 looking
1377 for one where TARGET appears on the RHS. */
1378 if (follow_assert_exprs
)
1380 /* Now see if that "other operand" is op0, following the chain
1381 of ASSERT_EXPRs if necessary. */
1382 gimple
*op0_def
= SSA_NAME_DEF_STMT (op0
);
1383 while (op0
!= target
1384 && gimple_assign_single_p (op0_def
)
1385 && TREE_CODE (gimple_assign_rhs1 (op0_def
)) == ASSERT_EXPR
)
1387 op0
= TREE_OPERAND (gimple_assign_rhs1 (op0_def
), 0);
1388 if (TREE_CODE (op0
) != SSA_NAME
)
1390 op0_def
= SSA_NAME_DEF_STMT (op0
);
1394 /* If we did not find our target SSA_NAME, then this is not
1395 an overflow test. */
1399 tree type
= TREE_TYPE (op0
);
1400 wide_int max
= wi::max_value (TYPE_PRECISION (type
), UNSIGNED
);
1401 tree inc
= gimple_assign_rhs2 (op1_def
);
1403 *new_cst
= wide_int_to_tree (type
, max
+ wi::to_wide (inc
));
1405 *new_cst
= wide_int_to_tree (type
, max
- wi::to_wide (inc
));
1412 /* OP0 CODE OP1 is a comparison. Examine the comparison and potentially
1413 OP1's defining statement to see if it ultimately has the form
1414 OP0 CODE (OP0 PLUS INTEGER_CST)
1416 If so, return TRUE indicating this is an overflow test and store into
1417 *NEW_CST an updated constant that can be used in a narrowed range test.
1419 These statements are left as-is in the IL to facilitate discovery of
1420 {ADD,SUB}_OVERFLOW sequences later in the optimizer pipeline. But
1421 the alternate range representation is often useful within VRP. */
1424 overflow_comparison_p (tree_code code
, tree name
, tree val
,
1425 bool use_equiv_p
, tree
*new_cst
)
1427 if (overflow_comparison_p_1 (code
, name
, val
, use_equiv_p
, false, new_cst
))
1429 return overflow_comparison_p_1 (swap_tree_comparison (code
), val
, name
,
1430 use_equiv_p
, true, new_cst
);
1434 /* Try to register an edge assertion for SSA name NAME on edge E for
1435 the condition COND contributing to the conditional jump pointed to by BSI.
1436 Invert the condition COND if INVERT is true. */
1439 register_edge_assert_for_2 (tree name
, edge e
,
1440 enum tree_code cond_code
,
1441 tree cond_op0
, tree cond_op1
, bool invert
,
1442 vec
<assert_info
> &asserts
)
1445 enum tree_code comp_code
;
1447 if (!extract_code_and_val_from_cond_with_ops (name
, cond_code
,
1450 invert
, &comp_code
, &val
))
1453 /* Queue the assert. */
1455 if (overflow_comparison_p (comp_code
, name
, val
, false, &x
))
1457 enum tree_code new_code
= ((comp_code
== GT_EXPR
|| comp_code
== GE_EXPR
)
1458 ? GT_EXPR
: LE_EXPR
);
1459 add_assert_info (asserts
, name
, name
, new_code
, x
);
1461 add_assert_info (asserts
, name
, name
, comp_code
, val
);
1463 /* In the case of NAME <= CST and NAME being defined as
1464 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
1465 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
1466 This catches range and anti-range tests. */
1467 if ((comp_code
== LE_EXPR
1468 || comp_code
== GT_EXPR
)
1469 && TREE_CODE (val
) == INTEGER_CST
1470 && TYPE_UNSIGNED (TREE_TYPE (val
)))
1472 gimple
*def_stmt
= SSA_NAME_DEF_STMT (name
);
1473 tree cst2
= NULL_TREE
, name2
= NULL_TREE
, name3
= NULL_TREE
;
1475 /* Extract CST2 from the (optional) addition. */
1476 if (is_gimple_assign (def_stmt
)
1477 && gimple_assign_rhs_code (def_stmt
) == PLUS_EXPR
)
1479 name2
= gimple_assign_rhs1 (def_stmt
);
1480 cst2
= gimple_assign_rhs2 (def_stmt
);
1481 if (TREE_CODE (name2
) == SSA_NAME
1482 && TREE_CODE (cst2
) == INTEGER_CST
)
1483 def_stmt
= SSA_NAME_DEF_STMT (name2
);
1486 /* Extract NAME2 from the (optional) sign-changing cast. */
1487 if (gimple_assign_cast_p (def_stmt
))
1489 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt
))
1490 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt
)))
1491 && (TYPE_PRECISION (gimple_expr_type (def_stmt
))
1492 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt
)))))
1493 name3
= gimple_assign_rhs1 (def_stmt
);
1496 /* If name3 is used later, create an ASSERT_EXPR for it. */
1497 if (name3
!= NULL_TREE
1498 && TREE_CODE (name3
) == SSA_NAME
1499 && (cst2
== NULL_TREE
1500 || TREE_CODE (cst2
) == INTEGER_CST
)
1501 && INTEGRAL_TYPE_P (TREE_TYPE (name3
)))
1505 /* Build an expression for the range test. */
1506 tmp
= build1 (NOP_EXPR
, TREE_TYPE (name
), name3
);
1507 if (cst2
!= NULL_TREE
)
1508 tmp
= build2 (PLUS_EXPR
, TREE_TYPE (name
), tmp
, cst2
);
1509 add_assert_info (asserts
, name3
, tmp
, comp_code
, val
);
1512 /* If name2 is used later, create an ASSERT_EXPR for it. */
1513 if (name2
!= NULL_TREE
1514 && TREE_CODE (name2
) == SSA_NAME
1515 && TREE_CODE (cst2
) == INTEGER_CST
1516 && INTEGRAL_TYPE_P (TREE_TYPE (name2
)))
1520 /* Build an expression for the range test. */
1522 if (TREE_TYPE (name
) != TREE_TYPE (name2
))
1523 tmp
= build1 (NOP_EXPR
, TREE_TYPE (name
), tmp
);
1524 if (cst2
!= NULL_TREE
)
1525 tmp
= build2 (PLUS_EXPR
, TREE_TYPE (name
), tmp
, cst2
);
1526 add_assert_info (asserts
, name2
, tmp
, comp_code
, val
);
1530 /* In the case of post-in/decrement tests like if (i++) ... and uses
1531 of the in/decremented value on the edge the extra name we want to
1532 assert for is not on the def chain of the name compared. Instead
1533 it is in the set of use stmts.
1534 Similar cases happen for conversions that were simplified through
1535 fold_{sign_changed,widened}_comparison. */
1536 if ((comp_code
== NE_EXPR
1537 || comp_code
== EQ_EXPR
)
1538 && TREE_CODE (val
) == INTEGER_CST
)
1540 imm_use_iterator ui
;
1542 FOR_EACH_IMM_USE_STMT (use_stmt
, ui
, name
)
1544 if (!is_gimple_assign (use_stmt
))
1547 /* Cut off to use-stmts that are dominating the predecessor. */
1548 if (!dominated_by_p (CDI_DOMINATORS
, e
->src
, gimple_bb (use_stmt
)))
1551 tree name2
= gimple_assign_lhs (use_stmt
);
1552 if (TREE_CODE (name2
) != SSA_NAME
)
1555 enum tree_code code
= gimple_assign_rhs_code (use_stmt
);
1557 if (code
== PLUS_EXPR
1558 || code
== MINUS_EXPR
)
1560 cst
= gimple_assign_rhs2 (use_stmt
);
1561 if (TREE_CODE (cst
) != INTEGER_CST
)
1563 cst
= int_const_binop (code
, val
, cst
);
1565 else if (CONVERT_EXPR_CODE_P (code
))
1567 /* For truncating conversions we cannot record
1569 if (comp_code
== NE_EXPR
1570 && (TYPE_PRECISION (TREE_TYPE (name2
))
1571 < TYPE_PRECISION (TREE_TYPE (name
))))
1573 cst
= fold_convert (TREE_TYPE (name2
), val
);
1578 if (TREE_OVERFLOW_P (cst
))
1579 cst
= drop_tree_overflow (cst
);
1580 add_assert_info (asserts
, name2
, name2
, comp_code
, cst
);
1584 if (TREE_CODE_CLASS (comp_code
) == tcc_comparison
1585 && TREE_CODE (val
) == INTEGER_CST
)
1587 gimple
*def_stmt
= SSA_NAME_DEF_STMT (name
);
1588 tree name2
= NULL_TREE
, names
[2], cst2
= NULL_TREE
;
1589 tree val2
= NULL_TREE
;
1590 unsigned int prec
= TYPE_PRECISION (TREE_TYPE (val
));
1591 wide_int mask
= wi::zero (prec
);
1592 unsigned int nprec
= prec
;
1593 enum tree_code rhs_code
= ERROR_MARK
;
1595 if (is_gimple_assign (def_stmt
))
1596 rhs_code
= gimple_assign_rhs_code (def_stmt
);
1598 /* In the case of NAME != CST1 where NAME = A +- CST2 we can
1599 assert that A != CST1 -+ CST2. */
1600 if ((comp_code
== EQ_EXPR
|| comp_code
== NE_EXPR
)
1601 && (rhs_code
== PLUS_EXPR
|| rhs_code
== MINUS_EXPR
))
1603 tree op0
= gimple_assign_rhs1 (def_stmt
);
1604 tree op1
= gimple_assign_rhs2 (def_stmt
);
1605 if (TREE_CODE (op0
) == SSA_NAME
1606 && TREE_CODE (op1
) == INTEGER_CST
)
1608 enum tree_code reverse_op
= (rhs_code
== PLUS_EXPR
1609 ? MINUS_EXPR
: PLUS_EXPR
);
1610 op1
= int_const_binop (reverse_op
, val
, op1
);
1611 if (TREE_OVERFLOW (op1
))
1612 op1
= drop_tree_overflow (op1
);
1613 add_assert_info (asserts
, op0
, op0
, comp_code
, op1
);
1617 /* Add asserts for NAME cmp CST and NAME being defined
1618 as NAME = (int) NAME2. */
1619 if (!TYPE_UNSIGNED (TREE_TYPE (val
))
1620 && (comp_code
== LE_EXPR
|| comp_code
== LT_EXPR
1621 || comp_code
== GT_EXPR
|| comp_code
== GE_EXPR
)
1622 && gimple_assign_cast_p (def_stmt
))
1624 name2
= gimple_assign_rhs1 (def_stmt
);
1625 if (CONVERT_EXPR_CODE_P (rhs_code
)
1626 && TREE_CODE (name2
) == SSA_NAME
1627 && INTEGRAL_TYPE_P (TREE_TYPE (name2
))
1628 && TYPE_UNSIGNED (TREE_TYPE (name2
))
1629 && prec
== TYPE_PRECISION (TREE_TYPE (name2
))
1630 && (comp_code
== LE_EXPR
|| comp_code
== GT_EXPR
1631 || !tree_int_cst_equal (val
,
1632 TYPE_MIN_VALUE (TREE_TYPE (val
)))))
1635 enum tree_code new_comp_code
= comp_code
;
1637 cst
= fold_convert (TREE_TYPE (name2
),
1638 TYPE_MIN_VALUE (TREE_TYPE (val
)));
1639 /* Build an expression for the range test. */
1640 tmp
= build2 (PLUS_EXPR
, TREE_TYPE (name2
), name2
, cst
);
1641 cst
= fold_build2 (PLUS_EXPR
, TREE_TYPE (name2
), cst
,
1642 fold_convert (TREE_TYPE (name2
), val
));
1643 if (comp_code
== LT_EXPR
|| comp_code
== GE_EXPR
)
1645 new_comp_code
= comp_code
== LT_EXPR
? LE_EXPR
: GT_EXPR
;
1646 cst
= fold_build2 (MINUS_EXPR
, TREE_TYPE (name2
), cst
,
1647 build_int_cst (TREE_TYPE (name2
), 1));
1649 add_assert_info (asserts
, name2
, tmp
, new_comp_code
, cst
);
1653 /* Add asserts for NAME cmp CST and NAME being defined as
1654 NAME = NAME2 >> CST2.
1656 Extract CST2 from the right shift. */
1657 if (rhs_code
== RSHIFT_EXPR
)
1659 name2
= gimple_assign_rhs1 (def_stmt
);
1660 cst2
= gimple_assign_rhs2 (def_stmt
);
1661 if (TREE_CODE (name2
) == SSA_NAME
1662 && tree_fits_uhwi_p (cst2
)
1663 && INTEGRAL_TYPE_P (TREE_TYPE (name2
))
1664 && IN_RANGE (tree_to_uhwi (cst2
), 1, prec
- 1)
1665 && type_has_mode_precision_p (TREE_TYPE (val
)))
1667 mask
= wi::mask (tree_to_uhwi (cst2
), false, prec
);
1668 val2
= fold_binary (LSHIFT_EXPR
, TREE_TYPE (val
), val
, cst2
);
1671 if (val2
!= NULL_TREE
1672 && TREE_CODE (val2
) == INTEGER_CST
1673 && simple_cst_equal (fold_build2 (RSHIFT_EXPR
,
1677 enum tree_code new_comp_code
= comp_code
;
1681 if (comp_code
== EQ_EXPR
|| comp_code
== NE_EXPR
)
1683 if (!TYPE_UNSIGNED (TREE_TYPE (val
)))
1685 tree type
= build_nonstandard_integer_type (prec
, 1);
1686 tmp
= build1 (NOP_EXPR
, type
, name2
);
1687 val2
= fold_convert (type
, val2
);
1689 tmp
= fold_build2 (MINUS_EXPR
, TREE_TYPE (tmp
), tmp
, val2
);
1690 new_val
= wide_int_to_tree (TREE_TYPE (tmp
), mask
);
1691 new_comp_code
= comp_code
== EQ_EXPR
? LE_EXPR
: GT_EXPR
;
1693 else if (comp_code
== LT_EXPR
|| comp_code
== GE_EXPR
)
1696 = wi::min_value (prec
, TYPE_SIGN (TREE_TYPE (val
)));
1698 if (minval
== wi::to_wide (new_val
))
1699 new_val
= NULL_TREE
;
1704 = wi::max_value (prec
, TYPE_SIGN (TREE_TYPE (val
)));
1705 mask
|= wi::to_wide (val2
);
1706 if (wi::eq_p (mask
, maxval
))
1707 new_val
= NULL_TREE
;
1709 new_val
= wide_int_to_tree (TREE_TYPE (val2
), mask
);
1713 add_assert_info (asserts
, name2
, tmp
, new_comp_code
, new_val
);
1716 /* If we have a conversion that doesn't change the value of the source
1717 simply register the same assert for it. */
1718 if (CONVERT_EXPR_CODE_P (rhs_code
))
1720 wide_int rmin
, rmax
;
1721 tree rhs1
= gimple_assign_rhs1 (def_stmt
);
1722 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1
))
1723 && TREE_CODE (rhs1
) == SSA_NAME
1724 /* Make sure the relation preserves the upper/lower boundary of
1725 the range conservatively. */
1726 && (comp_code
== NE_EXPR
1727 || comp_code
== EQ_EXPR
1728 || (TYPE_SIGN (TREE_TYPE (name
))
1729 == TYPE_SIGN (TREE_TYPE (rhs1
)))
1730 || ((comp_code
== LE_EXPR
1731 || comp_code
== LT_EXPR
)
1732 && !TYPE_UNSIGNED (TREE_TYPE (rhs1
)))
1733 || ((comp_code
== GE_EXPR
1734 || comp_code
== GT_EXPR
)
1735 && TYPE_UNSIGNED (TREE_TYPE (rhs1
))))
1736 /* And the conversion does not alter the value we compare
1737 against and all values in rhs1 can be represented in
1738 the converted to type. */
1739 && int_fits_type_p (val
, TREE_TYPE (rhs1
))
1740 && ((TYPE_PRECISION (TREE_TYPE (name
))
1741 > TYPE_PRECISION (TREE_TYPE (rhs1
)))
1742 || (get_range_info (rhs1
, &rmin
, &rmax
) == VR_RANGE
1743 && wi::fits_to_tree_p (rmin
, TREE_TYPE (name
))
1744 && wi::fits_to_tree_p (rmax
, TREE_TYPE (name
)))))
1745 add_assert_info (asserts
, rhs1
, rhs1
,
1746 comp_code
, fold_convert (TREE_TYPE (rhs1
), val
));
1749 /* Add asserts for NAME cmp CST and NAME being defined as
1750 NAME = NAME2 & CST2.
1752 Extract CST2 from the and.
1755 NAME = (unsigned) NAME2;
1756 casts where NAME's type is unsigned and has smaller precision
1757 than NAME2's type as if it was NAME = NAME2 & MASK. */
1758 names
[0] = NULL_TREE
;
1759 names
[1] = NULL_TREE
;
1761 if (rhs_code
== BIT_AND_EXPR
1762 || (CONVERT_EXPR_CODE_P (rhs_code
)
1763 && INTEGRAL_TYPE_P (TREE_TYPE (val
))
1764 && TYPE_UNSIGNED (TREE_TYPE (val
))
1765 && TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt
)))
1768 name2
= gimple_assign_rhs1 (def_stmt
);
1769 if (rhs_code
== BIT_AND_EXPR
)
1770 cst2
= gimple_assign_rhs2 (def_stmt
);
1773 cst2
= TYPE_MAX_VALUE (TREE_TYPE (val
));
1774 nprec
= TYPE_PRECISION (TREE_TYPE (name2
));
1776 if (TREE_CODE (name2
) == SSA_NAME
1777 && INTEGRAL_TYPE_P (TREE_TYPE (name2
))
1778 && TREE_CODE (cst2
) == INTEGER_CST
1779 && !integer_zerop (cst2
)
1781 || TYPE_UNSIGNED (TREE_TYPE (val
))))
1783 gimple
*def_stmt2
= SSA_NAME_DEF_STMT (name2
);
1784 if (gimple_assign_cast_p (def_stmt2
))
1786 names
[1] = gimple_assign_rhs1 (def_stmt2
);
1787 if (!CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt2
))
1788 || TREE_CODE (names
[1]) != SSA_NAME
1789 || !INTEGRAL_TYPE_P (TREE_TYPE (names
[1]))
1790 || (TYPE_PRECISION (TREE_TYPE (name2
))
1791 != TYPE_PRECISION (TREE_TYPE (names
[1]))))
1792 names
[1] = NULL_TREE
;
1797 if (names
[0] || names
[1])
1799 wide_int minv
, maxv
, valv
, cst2v
;
1800 wide_int tem
, sgnbit
;
1801 bool valid_p
= false, valn
, cst2n
;
1802 enum tree_code ccode
= comp_code
;
1804 valv
= wide_int::from (wi::to_wide (val
), nprec
, UNSIGNED
);
1805 cst2v
= wide_int::from (wi::to_wide (cst2
), nprec
, UNSIGNED
);
1806 valn
= wi::neg_p (valv
, TYPE_SIGN (TREE_TYPE (val
)));
1807 cst2n
= wi::neg_p (cst2v
, TYPE_SIGN (TREE_TYPE (val
)));
1808 /* If CST2 doesn't have most significant bit set,
1809 but VAL is negative, we have comparison like
1810 if ((x & 0x123) > -4) (always true). Just give up. */
1814 sgnbit
= wi::set_bit_in_zero (nprec
- 1, nprec
);
1816 sgnbit
= wi::zero (nprec
);
1817 minv
= valv
& cst2v
;
1821 /* Minimum unsigned value for equality is VAL & CST2
1822 (should be equal to VAL, otherwise we probably should
1823 have folded the comparison into false) and
1824 maximum unsigned value is VAL | ~CST2. */
1825 maxv
= valv
| ~cst2v
;
1830 tem
= valv
| ~cst2v
;
1831 /* If VAL is 0, handle (X & CST2) != 0 as (X & CST2) > 0U. */
1835 sgnbit
= wi::zero (nprec
);
1838 /* If (VAL | ~CST2) is all ones, handle it as
1839 (X & CST2) < VAL. */
1844 sgnbit
= wi::zero (nprec
);
1847 if (!cst2n
&& wi::neg_p (cst2v
))
1848 sgnbit
= wi::set_bit_in_zero (nprec
- 1, nprec
);
1857 if (tem
== wi::mask (nprec
- 1, false, nprec
))
1863 sgnbit
= wi::zero (nprec
);
1868 /* Minimum unsigned value for >= if (VAL & CST2) == VAL
1869 is VAL and maximum unsigned value is ~0. For signed
1870 comparison, if CST2 doesn't have most significant bit
1871 set, handle it similarly. If CST2 has MSB set,
1872 the minimum is the same, and maximum is ~0U/2. */
1875 /* If (VAL & CST2) != VAL, X & CST2 can't be equal to
1877 minv
= masked_increment (valv
, cst2v
, sgnbit
, nprec
);
1881 maxv
= wi::mask (nprec
- (cst2n
? 1 : 0), false, nprec
);
1887 /* Find out smallest MINV where MINV > VAL
1888 && (MINV & CST2) == MINV, if any. If VAL is signed and
1889 CST2 has MSB set, compute it biased by 1 << (nprec - 1). */
1890 minv
= masked_increment (valv
, cst2v
, sgnbit
, nprec
);
1893 maxv
= wi::mask (nprec
- (cst2n
? 1 : 0), false, nprec
);
1898 /* Minimum unsigned value for <= is 0 and maximum
1899 unsigned value is VAL | ~CST2 if (VAL & CST2) == VAL.
1900 Otherwise, find smallest VAL2 where VAL2 > VAL
1901 && (VAL2 & CST2) == VAL2 and use (VAL2 - 1) | ~CST2
1903 For signed comparison, if CST2 doesn't have most
1904 significant bit set, handle it similarly. If CST2 has
1905 MSB set, the maximum is the same and minimum is INT_MIN. */
1910 maxv
= masked_increment (valv
, cst2v
, sgnbit
, nprec
);
1922 /* Minimum unsigned value for < is 0 and maximum
1923 unsigned value is (VAL-1) | ~CST2 if (VAL & CST2) == VAL.
1924 Otherwise, find smallest VAL2 where VAL2 > VAL
1925 && (VAL2 & CST2) == VAL2 and use (VAL2 - 1) | ~CST2
1927 For signed comparison, if CST2 doesn't have most
1928 significant bit set, handle it similarly. If CST2 has
1929 MSB set, the maximum is the same and minimum is INT_MIN. */
1938 maxv
= masked_increment (valv
, cst2v
, sgnbit
, nprec
);
1952 && (maxv
- minv
) != -1)
1954 tree tmp
, new_val
, type
;
1957 for (i
= 0; i
< 2; i
++)
1960 wide_int maxv2
= maxv
;
1962 type
= TREE_TYPE (names
[i
]);
1963 if (!TYPE_UNSIGNED (type
))
1965 type
= build_nonstandard_integer_type (nprec
, 1);
1966 tmp
= build1 (NOP_EXPR
, type
, names
[i
]);
1970 tmp
= build2 (PLUS_EXPR
, type
, tmp
,
1971 wide_int_to_tree (type
, -minv
));
1972 maxv2
= maxv
- minv
;
1974 new_val
= wide_int_to_tree (type
, maxv2
);
1975 add_assert_info (asserts
, names
[i
], tmp
, LE_EXPR
, new_val
);
1982 /* OP is an operand of a truth value expression which is known to have
1983 a particular value. Register any asserts for OP and for any
1984 operands in OP's defining statement.
1986 If CODE is EQ_EXPR, then we want to register OP is zero (false),
1987 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
1990 register_edge_assert_for_1 (tree op
, enum tree_code code
,
1991 edge e
, vec
<assert_info
> &asserts
)
1995 enum tree_code rhs_code
;
1997 /* We only care about SSA_NAMEs. */
1998 if (TREE_CODE (op
) != SSA_NAME
)
2001 /* We know that OP will have a zero or nonzero value. */
2002 val
= build_int_cst (TREE_TYPE (op
), 0);
2003 add_assert_info (asserts
, op
, op
, code
, val
);
2005 /* Now look at how OP is set. If it's set from a comparison,
2006 a truth operation or some bit operations, then we may be able
2007 to register information about the operands of that assignment. */
2008 op_def
= SSA_NAME_DEF_STMT (op
);
2009 if (gimple_code (op_def
) != GIMPLE_ASSIGN
)
2012 rhs_code
= gimple_assign_rhs_code (op_def
);
2014 if (TREE_CODE_CLASS (rhs_code
) == tcc_comparison
)
2016 bool invert
= (code
== EQ_EXPR
? true : false);
2017 tree op0
= gimple_assign_rhs1 (op_def
);
2018 tree op1
= gimple_assign_rhs2 (op_def
);
2020 if (TREE_CODE (op0
) == SSA_NAME
)
2021 register_edge_assert_for_2 (op0
, e
, rhs_code
, op0
, op1
, invert
, asserts
);
2022 if (TREE_CODE (op1
) == SSA_NAME
)
2023 register_edge_assert_for_2 (op1
, e
, rhs_code
, op0
, op1
, invert
, asserts
);
2025 else if ((code
== NE_EXPR
2026 && gimple_assign_rhs_code (op_def
) == BIT_AND_EXPR
)
2028 && gimple_assign_rhs_code (op_def
) == BIT_IOR_EXPR
))
2030 /* Recurse on each operand. */
2031 tree op0
= gimple_assign_rhs1 (op_def
);
2032 tree op1
= gimple_assign_rhs2 (op_def
);
2033 if (TREE_CODE (op0
) == SSA_NAME
2034 && has_single_use (op0
))
2035 register_edge_assert_for_1 (op0
, code
, e
, asserts
);
2036 if (TREE_CODE (op1
) == SSA_NAME
2037 && has_single_use (op1
))
2038 register_edge_assert_for_1 (op1
, code
, e
, asserts
);
2040 else if (gimple_assign_rhs_code (op_def
) == BIT_NOT_EXPR
2041 && TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (op_def
))) == 1)
2043 /* Recurse, flipping CODE. */
2044 code
= invert_tree_comparison (code
, false);
2045 register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
), code
, e
, asserts
);
2047 else if (gimple_assign_rhs_code (op_def
) == SSA_NAME
)
2049 /* Recurse through the copy. */
2050 register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
), code
, e
, asserts
);
2052 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def
)))
2054 /* Recurse through the type conversion, unless it is a narrowing
2055 conversion or conversion from non-integral type. */
2056 tree rhs
= gimple_assign_rhs1 (op_def
);
2057 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs
))
2058 && (TYPE_PRECISION (TREE_TYPE (rhs
))
2059 <= TYPE_PRECISION (TREE_TYPE (op
))))
2060 register_edge_assert_for_1 (rhs
, code
, e
, asserts
);
2064 /* Check if comparison
2065 NAME COND_OP INTEGER_CST
2067 (X & 11...100..0) COND_OP XX...X00...0
2068 Such comparison can yield assertions like
2071 in case of COND_OP being EQ_EXPR or
2074 in case of NE_EXPR. */
2077 is_masked_range_test (tree name
, tree valt
, enum tree_code cond_code
,
2078 tree
*new_name
, tree
*low
, enum tree_code
*low_code
,
2079 tree
*high
, enum tree_code
*high_code
)
2081 gimple
*def_stmt
= SSA_NAME_DEF_STMT (name
);
2083 if (!is_gimple_assign (def_stmt
)
2084 || gimple_assign_rhs_code (def_stmt
) != BIT_AND_EXPR
)
2087 tree t
= gimple_assign_rhs1 (def_stmt
);
2088 tree maskt
= gimple_assign_rhs2 (def_stmt
);
2089 if (TREE_CODE (t
) != SSA_NAME
|| TREE_CODE (maskt
) != INTEGER_CST
)
2092 wi::tree_to_wide_ref mask
= wi::to_wide (maskt
);
2093 wide_int inv_mask
= ~mask
;
2094 /* Must have been removed by now so don't bother optimizing. */
2095 if (mask
== 0 || inv_mask
== 0)
2098 /* Assume VALT is INTEGER_CST. */
2099 wi::tree_to_wide_ref val
= wi::to_wide (valt
);
2101 if ((inv_mask
& (inv_mask
+ 1)) != 0
2102 || (val
& mask
) != val
)
2105 bool is_range
= cond_code
== EQ_EXPR
;
2107 tree type
= TREE_TYPE (t
);
2108 wide_int min
= wi::min_value (type
),
2109 max
= wi::max_value (type
);
2113 *low_code
= val
== min
? ERROR_MARK
: GE_EXPR
;
2114 *high_code
= val
== max
? ERROR_MARK
: LE_EXPR
;
2118 /* We can still generate assertion if one of alternatives
2119 is known to always be false. */
2122 *low_code
= (enum tree_code
) 0;
2123 *high_code
= GT_EXPR
;
2125 else if ((val
| inv_mask
) == max
)
2127 *low_code
= LT_EXPR
;
2128 *high_code
= (enum tree_code
) 0;
2135 *low
= wide_int_to_tree (type
, val
);
2136 *high
= wide_int_to_tree (type
, val
| inv_mask
);
2141 /* Try to register an edge assertion for SSA name NAME on edge E for
2142 the condition COND contributing to the conditional jump pointed to by
2146 register_edge_assert_for (tree name
, edge e
,
2147 enum tree_code cond_code
, tree cond_op0
,
2148 tree cond_op1
, vec
<assert_info
> &asserts
)
2151 enum tree_code comp_code
;
2152 bool is_else_edge
= (e
->flags
& EDGE_FALSE_VALUE
) != 0;
2154 /* Do not attempt to infer anything in names that flow through
2156 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name
))
2159 if (!extract_code_and_val_from_cond_with_ops (name
, cond_code
,
2165 /* Register ASSERT_EXPRs for name. */
2166 register_edge_assert_for_2 (name
, e
, cond_code
, cond_op0
,
2167 cond_op1
, is_else_edge
, asserts
);
2170 /* If COND is effectively an equality test of an SSA_NAME against
2171 the value zero or one, then we may be able to assert values
2172 for SSA_NAMEs which flow into COND. */
2174 /* In the case of NAME == 1 or NAME != 0, for BIT_AND_EXPR defining
2175 statement of NAME we can assert both operands of the BIT_AND_EXPR
2176 have nonzero value. */
2177 if (((comp_code
== EQ_EXPR
&& integer_onep (val
))
2178 || (comp_code
== NE_EXPR
&& integer_zerop (val
))))
2180 gimple
*def_stmt
= SSA_NAME_DEF_STMT (name
);
2182 if (is_gimple_assign (def_stmt
)
2183 && gimple_assign_rhs_code (def_stmt
) == BIT_AND_EXPR
)
2185 tree op0
= gimple_assign_rhs1 (def_stmt
);
2186 tree op1
= gimple_assign_rhs2 (def_stmt
);
2187 register_edge_assert_for_1 (op0
, NE_EXPR
, e
, asserts
);
2188 register_edge_assert_for_1 (op1
, NE_EXPR
, e
, asserts
);
2192 /* In the case of NAME == 0 or NAME != 1, for BIT_IOR_EXPR defining
2193 statement of NAME we can assert both operands of the BIT_IOR_EXPR
2195 if (((comp_code
== EQ_EXPR
&& integer_zerop (val
))
2196 || (comp_code
== NE_EXPR
&& integer_onep (val
))))
2198 gimple
*def_stmt
= SSA_NAME_DEF_STMT (name
);
2200 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
2201 necessarily zero value, or if type-precision is one. */
2202 if (is_gimple_assign (def_stmt
)
2203 && (gimple_assign_rhs_code (def_stmt
) == BIT_IOR_EXPR
2204 && (TYPE_PRECISION (TREE_TYPE (name
)) == 1
2205 || comp_code
== EQ_EXPR
)))
2207 tree op0
= gimple_assign_rhs1 (def_stmt
);
2208 tree op1
= gimple_assign_rhs2 (def_stmt
);
2209 register_edge_assert_for_1 (op0
, EQ_EXPR
, e
, asserts
);
2210 register_edge_assert_for_1 (op1
, EQ_EXPR
, e
, asserts
);
2214 /* Sometimes we can infer ranges from (NAME & MASK) == VALUE. */
2215 if ((comp_code
== EQ_EXPR
|| comp_code
== NE_EXPR
)
2216 && TREE_CODE (val
) == INTEGER_CST
)
2218 enum tree_code low_code
, high_code
;
2220 if (is_masked_range_test (name
, val
, comp_code
, &name
, &low
,
2221 &low_code
, &high
, &high_code
))
2223 if (low_code
!= ERROR_MARK
)
2224 register_edge_assert_for_2 (name
, e
, low_code
, name
,
2225 low
, /*invert*/false, asserts
);
2226 if (high_code
!= ERROR_MARK
)
2227 register_edge_assert_for_2 (name
, e
, high_code
, name
,
2228 high
, /*invert*/false, asserts
);
2240 __builtin_unreachable ();
2242 x_5 = ASSERT_EXPR <x_3, ...>;
2243 If x_3 has no other immediate uses (checked by caller),
2244 var is the x_3 var from ASSERT_EXPR, we can clear low 5 bits
2245 from the non-zero bitmask. */
2248 maybe_set_nonzero_bits (edge e
, tree var
)
2250 basic_block cond_bb
= e
->src
;
2251 gimple
*stmt
= last_stmt (cond_bb
);
2255 || gimple_code (stmt
) != GIMPLE_COND
2256 || gimple_cond_code (stmt
) != ((e
->flags
& EDGE_TRUE_VALUE
)
2257 ? EQ_EXPR
: NE_EXPR
)
2258 || TREE_CODE (gimple_cond_lhs (stmt
)) != SSA_NAME
2259 || !integer_zerop (gimple_cond_rhs (stmt
)))
2262 stmt
= SSA_NAME_DEF_STMT (gimple_cond_lhs (stmt
));
2263 if (!is_gimple_assign (stmt
)
2264 || gimple_assign_rhs_code (stmt
) != BIT_AND_EXPR
2265 || TREE_CODE (gimple_assign_rhs2 (stmt
)) != INTEGER_CST
)
2267 if (gimple_assign_rhs1 (stmt
) != var
)
2271 if (TREE_CODE (gimple_assign_rhs1 (stmt
)) != SSA_NAME
)
2273 stmt2
= SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt
));
2274 if (!gimple_assign_cast_p (stmt2
)
2275 || gimple_assign_rhs1 (stmt2
) != var
2276 || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt2
))
2277 || (TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (stmt
)))
2278 != TYPE_PRECISION (TREE_TYPE (var
))))
2281 cst
= gimple_assign_rhs2 (stmt
);
2282 set_nonzero_bits (var
, wi::bit_and_not (get_nonzero_bits (var
),
2283 wi::to_wide (cst
)));
2286 /* Return true if STMT is interesting for VRP. */
2289 stmt_interesting_for_vrp (gimple
*stmt
)
2291 if (gimple_code (stmt
) == GIMPLE_PHI
)
2293 tree res
= gimple_phi_result (stmt
);
2294 return (!virtual_operand_p (res
)
2295 && (INTEGRAL_TYPE_P (TREE_TYPE (res
))
2296 || POINTER_TYPE_P (TREE_TYPE (res
))));
2298 else if (is_gimple_assign (stmt
) || is_gimple_call (stmt
))
2300 tree lhs
= gimple_get_lhs (stmt
);
2302 /* In general, assignments with virtual operands are not useful
2303 for deriving ranges, with the obvious exception of calls to
2304 builtin functions. */
2305 if (lhs
&& TREE_CODE (lhs
) == SSA_NAME
2306 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
2307 || POINTER_TYPE_P (TREE_TYPE (lhs
)))
2308 && (is_gimple_call (stmt
)
2309 || !gimple_vuse (stmt
)))
2311 else if (is_gimple_call (stmt
) && gimple_call_internal_p (stmt
))
2312 switch (gimple_call_internal_fn (stmt
))
2314 case IFN_ADD_OVERFLOW
:
2315 case IFN_SUB_OVERFLOW
:
2316 case IFN_MUL_OVERFLOW
:
2317 case IFN_ATOMIC_COMPARE_EXCHANGE
:
2318 /* These internal calls return _Complex integer type,
2319 but are interesting to VRP nevertheless. */
2320 if (lhs
&& TREE_CODE (lhs
) == SSA_NAME
)
2327 else if (gimple_code (stmt
) == GIMPLE_COND
2328 || gimple_code (stmt
) == GIMPLE_SWITCH
)
2335 /* Return the LHS of any ASSERT_EXPR where OP appears as the first
2336 argument to the ASSERT_EXPR and in which the ASSERT_EXPR dominates
2337 BB. If no such ASSERT_EXPR is found, return OP. */
2340 lhs_of_dominating_assert (tree op
, basic_block bb
, gimple
*stmt
)
2342 imm_use_iterator imm_iter
;
2344 use_operand_p use_p
;
2346 if (TREE_CODE (op
) == SSA_NAME
)
2348 FOR_EACH_IMM_USE_FAST (use_p
, imm_iter
, op
)
2350 use_stmt
= USE_STMT (use_p
);
2351 if (use_stmt
!= stmt
2352 && gimple_assign_single_p (use_stmt
)
2353 && TREE_CODE (gimple_assign_rhs1 (use_stmt
)) == ASSERT_EXPR
2354 && TREE_OPERAND (gimple_assign_rhs1 (use_stmt
), 0) == op
2355 && dominated_by_p (CDI_DOMINATORS
, bb
, gimple_bb (use_stmt
)))
2356 return gimple_assign_lhs (use_stmt
);
2363 static class vr_values
*x_vr_values
;
2365 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
2366 that includes the value VAL. The search is restricted to the range
2367 [START_IDX, n - 1] where n is the size of VEC.
2369 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
2372 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
2373 it is placed in IDX and false is returned.
2375 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
2379 find_case_label_index (gswitch
*stmt
, size_t start_idx
, tree val
, size_t *idx
)
2381 size_t n
= gimple_switch_num_labels (stmt
);
2384 /* Find case label for minimum of the value range or the next one.
2385 At each iteration we are searching in [low, high - 1]. */
2387 for (low
= start_idx
, high
= n
; high
!= low
; )
2391 /* Note that i != high, so we never ask for n. */
2392 size_t i
= (high
+ low
) / 2;
2393 t
= gimple_switch_label (stmt
, i
);
2395 /* Cache the result of comparing CASE_LOW and val. */
2396 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
2400 /* Ranges cannot be empty. */
2409 if (CASE_HIGH (t
) != NULL
2410 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
2422 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
2423 for values between MIN and MAX. The first index is placed in MIN_IDX. The
2424 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
2425 then MAX_IDX < MIN_IDX.
2426 Returns true if the default label is not needed. */
2429 find_case_label_range (gswitch
*stmt
, tree min
, tree max
, size_t *min_idx
,
2433 bool min_take_default
= !find_case_label_index (stmt
, 1, min
, &i
);
2434 bool max_take_default
= !find_case_label_index (stmt
, i
, max
, &j
);
2438 && max_take_default
)
2440 /* Only the default case label reached.
2441 Return an empty range. */
2448 bool take_default
= min_take_default
|| max_take_default
;
2452 if (max_take_default
)
2455 /* If the case label range is continuous, we do not need
2456 the default case label. Verify that. */
2457 high
= CASE_LOW (gimple_switch_label (stmt
, i
));
2458 if (CASE_HIGH (gimple_switch_label (stmt
, i
)))
2459 high
= CASE_HIGH (gimple_switch_label (stmt
, i
));
2460 for (k
= i
+ 1; k
<= j
; ++k
)
2462 low
= CASE_LOW (gimple_switch_label (stmt
, k
));
2463 if (!integer_onep (int_const_binop (MINUS_EXPR
, low
, high
)))
2465 take_default
= true;
2469 if (CASE_HIGH (gimple_switch_label (stmt
, k
)))
2470 high
= CASE_HIGH (gimple_switch_label (stmt
, k
));
2475 return !take_default
;
2479 /* Given a SWITCH_STMT, return the case label that encompasses the
2480 known possible values for the switch operand. RANGE_OF_OP is a
2481 range for the known values of the switch operand. */
2484 find_case_label_range (gswitch
*switch_stmt
, const irange
*range_of_op
)
2486 if (range_of_op
->undefined_p ()
2487 || range_of_op
->varying_p ()
2488 || range_of_op
->symbolic_p ())
2492 tree op
= gimple_switch_index (switch_stmt
);
2493 tree type
= TREE_TYPE (op
);
2494 tree tmin
= wide_int_to_tree (type
, range_of_op
->lower_bound ());
2495 tree tmax
= wide_int_to_tree (type
, range_of_op
->upper_bound ());
2496 find_case_label_range (switch_stmt
, tmin
, tmax
, &i
, &j
);
2499 /* Look for exactly one label that encompasses the range of
2501 tree label
= gimple_switch_label (switch_stmt
, i
);
2503 = CASE_HIGH (label
) ? CASE_HIGH (label
) : CASE_LOW (label
);
2504 int_range_max
label_range (CASE_LOW (label
), case_high
);
2505 if (!types_compatible_p (label_range
.type (), range_of_op
->type ()))
2506 range_cast (label_range
, range_of_op
->type ());
2507 label_range
.intersect (range_of_op
);
2508 if (label_range
== *range_of_op
)
2513 /* If there are no labels at all, take the default. */
2514 return gimple_switch_label (switch_stmt
, 0);
2518 /* Otherwise, there are various labels that can encompass
2519 the range of operand. In which case, see if the range of
2520 the operand is entirely *outside* the bounds of all the
2521 (non-default) case labels. If so, take the default. */
2522 unsigned n
= gimple_switch_num_labels (switch_stmt
);
2523 tree min_label
= gimple_switch_label (switch_stmt
, 1);
2524 tree max_label
= gimple_switch_label (switch_stmt
, n
- 1);
2525 tree case_high
= CASE_HIGH (max_label
);
2527 case_high
= CASE_LOW (max_label
);
2528 int_range_max
label_range (CASE_LOW (min_label
), case_high
);
2529 if (!types_compatible_p (label_range
.type (), range_of_op
->type ()))
2530 range_cast (label_range
, range_of_op
->type ());
2531 label_range
.intersect (range_of_op
);
2532 if (label_range
.undefined_p ())
2533 return gimple_switch_label (switch_stmt
, 0);
2544 /* Location information for ASSERT_EXPRs. Each instance of this
2545 structure describes an ASSERT_EXPR for an SSA name. Since a single
2546 SSA name may have more than one assertion associated with it, these
2547 locations are kept in a linked list attached to the corresponding
2551 /* Basic block where the assertion would be inserted. */
2554 /* Some assertions need to be inserted on an edge (e.g., assertions
2555 generated by COND_EXPRs). In those cases, BB will be NULL. */
2558 /* Pointer to the statement that generated this assertion. */
2559 gimple_stmt_iterator si
;
2561 /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */
2562 enum tree_code comp_code
;
2564 /* Value being compared against. */
2567 /* Expression to compare. */
2570 /* Next node in the linked list. */
2574 /* Class to traverse the flowgraph looking for conditional jumps to
2575 insert ASSERT_EXPR range expressions. These range expressions are
2576 meant to provide information to optimizations that need to reason
2577 in terms of value ranges. They will not be expanded into RTL. */
2582 vrp_asserts (struct function
*fn
) : fun (fn
) { }
2584 void insert_range_assertions ();
2586 /* Convert range assertion expressions into the implied copies and
2587 copy propagate away the copies. */
2588 void remove_range_assertions ();
2590 /* Dump all the registered assertions for all the names to FILE. */
2593 /* Dump all the registered assertions for NAME to FILE. */
2594 void dump (FILE *file
, tree name
);
2596 /* Dump all the registered assertions for NAME to stderr. */
2597 void debug (tree name
)
2599 dump (stderr
, name
);
2602 /* Dump all the registered assertions for all the names to stderr. */
2609 /* Set of SSA names found live during the RPO traversal of the function
2610 for still active basic-blocks. */
2613 /* Function to work on. */
2614 struct function
*fun
;
2616 /* If bit I is present, it means that SSA name N_i has a list of
2617 assertions that should be inserted in the IL. */
2618 bitmap need_assert_for
;
2620 /* Array of locations lists where to insert assertions. ASSERTS_FOR[I]
2621 holds a list of ASSERT_LOCUS_T nodes that describe where
2622 ASSERT_EXPRs for SSA name N_I should be inserted. */
2623 assert_locus
**asserts_for
;
2625 /* Finish found ASSERTS for E and register them at GSI. */
2626 void finish_register_edge_assert_for (edge e
, gimple_stmt_iterator gsi
,
2627 vec
<assert_info
> &asserts
);
2629 /* Determine whether the outgoing edges of BB should receive an
2630 ASSERT_EXPR for each of the operands of BB's LAST statement. The
2631 last statement of BB must be a SWITCH_EXPR.
2633 If any of the sub-graphs rooted at BB have an interesting use of
2634 the predicate operands, an assert location node is added to the
2635 list of assertions for the corresponding operands. */
2636 void find_switch_asserts (basic_block bb
, gswitch
*last
);
2638 /* Do an RPO walk over the function computing SSA name liveness
2639 on-the-fly and deciding on assert expressions to insert. */
2640 void find_assert_locations ();
2642 /* Traverse all the statements in block BB looking for statements that
2643 may generate useful assertions for the SSA names in their operand.
2644 See method implementation comentary for more information. */
2645 void find_assert_locations_in_bb (basic_block bb
);
2647 /* Determine whether the outgoing edges of BB should receive an
2648 ASSERT_EXPR for each of the operands of BB's LAST statement.
2649 The last statement of BB must be a COND_EXPR.
2651 If any of the sub-graphs rooted at BB have an interesting use of
2652 the predicate operands, an assert location node is added to the
2653 list of assertions for the corresponding operands. */
2654 void find_conditional_asserts (basic_block bb
, gcond
*last
);
2656 /* Process all the insertions registered for every name N_i registered
2657 in NEED_ASSERT_FOR. The list of assertions to be inserted are
2658 found in ASSERTS_FOR[i]. */
2659 void process_assert_insertions ();
2661 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
2662 'EXPR COMP_CODE VAL' at a location that dominates block BB or
2663 E->DEST, then register this location as a possible insertion point
2664 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
2666 BB, E and SI provide the exact insertion point for the new
2667 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
2668 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
2669 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
2670 must not be NULL. */
2671 void register_new_assert_for (tree name
, tree expr
,
2672 enum tree_code comp_code
,
2673 tree val
, basic_block bb
,
2674 edge e
, gimple_stmt_iterator si
);
2676 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
2677 create a new SSA name N and return the assertion assignment
2678 'N = ASSERT_EXPR <V, V OP W>'. */
2679 gimple
*build_assert_expr_for (tree cond
, tree v
);
2681 /* Create an ASSERT_EXPR for NAME and insert it in the location
2682 indicated by LOC. Return true if we made any edge insertions. */
2683 bool process_assert_insertions_for (tree name
, assert_locus
*loc
);
2685 /* Qsort callback for sorting assert locations. */
2686 template <bool stable
> static int compare_assert_loc (const void *,
2689 /* Return false if EXPR is a predicate expression involving floating
2691 bool fp_predicate (gimple
*stmt
)
2693 GIMPLE_CHECK (stmt
, GIMPLE_COND
);
2694 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt
)));
2697 bool all_imm_uses_in_stmt_or_feed_cond (tree var
, gimple
*stmt
,
2698 basic_block cond_bb
);
2700 static int compare_case_labels (const void *, const void *);
2703 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
2704 create a new SSA name N and return the assertion assignment
2705 'N = ASSERT_EXPR <V, V OP W>'. */
2708 vrp_asserts::build_assert_expr_for (tree cond
, tree v
)
2713 gcc_assert (TREE_CODE (v
) == SSA_NAME
2714 && COMPARISON_CLASS_P (cond
));
2716 a
= build2 (ASSERT_EXPR
, TREE_TYPE (v
), v
, cond
);
2717 assertion
= gimple_build_assign (NULL_TREE
, a
);
2719 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
2720 operand of the ASSERT_EXPR. Create it so the new name and the old one
2721 are registered in the replacement table so that we can fix the SSA web
2722 after adding all the ASSERT_EXPRs. */
2723 tree new_def
= create_new_def_for (v
, assertion
, NULL
);
2724 /* Make sure we preserve abnormalness throughout an ASSERT_EXPR chain
2725 given we have to be able to fully propagate those out to re-create
2726 valid SSA when removing the asserts. */
2727 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (v
))
2728 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_def
) = 1;
2733 /* Dump all the registered assertions for NAME to FILE. */
2736 vrp_asserts::dump (FILE *file
, tree name
)
2740 fprintf (file
, "Assertions to be inserted for ");
2741 print_generic_expr (file
, name
);
2742 fprintf (file
, "\n");
2744 loc
= asserts_for
[SSA_NAME_VERSION (name
)];
2747 fprintf (file
, "\t");
2748 print_gimple_stmt (file
, gsi_stmt (loc
->si
), 0);
2749 fprintf (file
, "\n\tBB #%d", loc
->bb
->index
);
2752 fprintf (file
, "\n\tEDGE %d->%d", loc
->e
->src
->index
,
2753 loc
->e
->dest
->index
);
2754 dump_edge_info (file
, loc
->e
, dump_flags
, 0);
2756 fprintf (file
, "\n\tPREDICATE: ");
2757 print_generic_expr (file
, loc
->expr
);
2758 fprintf (file
, " %s ", get_tree_code_name (loc
->comp_code
));
2759 print_generic_expr (file
, loc
->val
);
2760 fprintf (file
, "\n\n");
2764 fprintf (file
, "\n");
2767 /* Dump all the registered assertions for all the names to FILE. */
2770 vrp_asserts::dump (FILE *file
)
2775 fprintf (file
, "\nASSERT_EXPRs to be inserted\n\n");
2776 EXECUTE_IF_SET_IN_BITMAP (need_assert_for
, 0, i
, bi
)
2777 dump (file
, ssa_name (i
));
2778 fprintf (file
, "\n");
2781 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
2782 'EXPR COMP_CODE VAL' at a location that dominates block BB or
2783 E->DEST, then register this location as a possible insertion point
2784 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
2786 BB, E and SI provide the exact insertion point for the new
2787 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
2788 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
2789 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
2790 must not be NULL. */
2793 vrp_asserts::register_new_assert_for (tree name
, tree expr
,
2794 enum tree_code comp_code
,
2798 gimple_stmt_iterator si
)
2800 assert_locus
*n
, *loc
, *last_loc
;
2801 basic_block dest_bb
;
2803 gcc_checking_assert (bb
== NULL
|| e
== NULL
);
2806 gcc_checking_assert (gimple_code (gsi_stmt (si
)) != GIMPLE_COND
2807 && gimple_code (gsi_stmt (si
)) != GIMPLE_SWITCH
);
2809 /* Never build an assert comparing against an integer constant with
2810 TREE_OVERFLOW set. This confuses our undefined overflow warning
2812 if (TREE_OVERFLOW_P (val
))
2813 val
= drop_tree_overflow (val
);
2815 /* The new assertion A will be inserted at BB or E. We need to
2816 determine if the new location is dominated by a previously
2817 registered location for A. If we are doing an edge insertion,
2818 assume that A will be inserted at E->DEST. Note that this is not
2821 If E is a critical edge, it will be split. But even if E is
2822 split, the new block will dominate the same set of blocks that
2825 The reverse, however, is not true, blocks dominated by E->DEST
2826 will not be dominated by the new block created to split E. So,
2827 if the insertion location is on a critical edge, we will not use
2828 the new location to move another assertion previously registered
2829 at a block dominated by E->DEST. */
2830 dest_bb
= (bb
) ? bb
: e
->dest
;
2832 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
2833 VAL at a block dominating DEST_BB, then we don't need to insert a new
2834 one. Similarly, if the same assertion already exists at a block
2835 dominated by DEST_BB and the new location is not on a critical
2836 edge, then update the existing location for the assertion (i.e.,
2837 move the assertion up in the dominance tree).
2839 Note, this is implemented as a simple linked list because there
2840 should not be more than a handful of assertions registered per
2841 name. If this becomes a performance problem, a table hashed by
2842 COMP_CODE and VAL could be implemented. */
2843 loc
= asserts_for
[SSA_NAME_VERSION (name
)];
2847 if (loc
->comp_code
== comp_code
2849 || operand_equal_p (loc
->val
, val
, 0))
2850 && (loc
->expr
== expr
2851 || operand_equal_p (loc
->expr
, expr
, 0)))
2853 /* If E is not a critical edge and DEST_BB
2854 dominates the existing location for the assertion, move
2855 the assertion up in the dominance tree by updating its
2856 location information. */
2857 if ((e
== NULL
|| !EDGE_CRITICAL_P (e
))
2858 && dominated_by_p (CDI_DOMINATORS
, loc
->bb
, dest_bb
))
2867 /* Update the last node of the list and move to the next one. */
2872 /* If we didn't find an assertion already registered for
2873 NAME COMP_CODE VAL, add a new one at the end of the list of
2874 assertions associated with NAME. */
2875 n
= XNEW (struct assert_locus
);
2879 n
->comp_code
= comp_code
;
2887 asserts_for
[SSA_NAME_VERSION (name
)] = n
;
2889 bitmap_set_bit (need_assert_for
, SSA_NAME_VERSION (name
));
2892 /* Finish found ASSERTS for E and register them at GSI. */
2895 vrp_asserts::finish_register_edge_assert_for (edge e
,
2896 gimple_stmt_iterator gsi
,
2897 vec
<assert_info
> &asserts
)
2899 for (unsigned i
= 0; i
< asserts
.length (); ++i
)
2900 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
2901 reachable from E. */
2902 if (live
.live_on_edge_p (asserts
[i
].name
, e
))
2903 register_new_assert_for (asserts
[i
].name
, asserts
[i
].expr
,
2904 asserts
[i
].comp_code
, asserts
[i
].val
,
2908 /* Determine whether the outgoing edges of BB should receive an
2909 ASSERT_EXPR for each of the operands of BB's LAST statement.
2910 The last statement of BB must be a COND_EXPR.
2912 If any of the sub-graphs rooted at BB have an interesting use of
2913 the predicate operands, an assert location node is added to the
2914 list of assertions for the corresponding operands. */
2917 vrp_asserts::find_conditional_asserts (basic_block bb
, gcond
*last
)
2919 gimple_stmt_iterator bsi
;
2925 bsi
= gsi_for_stmt (last
);
2927 /* Look for uses of the operands in each of the sub-graphs
2928 rooted at BB. We need to check each of the outgoing edges
2929 separately, so that we know what kind of ASSERT_EXPR to
2931 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2936 /* Register the necessary assertions for each operand in the
2937 conditional predicate. */
2938 auto_vec
<assert_info
, 8> asserts
;
2939 FOR_EACH_SSA_TREE_OPERAND (op
, last
, iter
, SSA_OP_USE
)
2940 register_edge_assert_for (op
, e
,
2941 gimple_cond_code (last
),
2942 gimple_cond_lhs (last
),
2943 gimple_cond_rhs (last
), asserts
);
2944 finish_register_edge_assert_for (e
, bsi
, asserts
);
2948 /* Compare two case labels sorting first by the destination bb index
2949 and then by the case value. */
2952 vrp_asserts::compare_case_labels (const void *p1
, const void *p2
)
2954 const struct case_info
*ci1
= (const struct case_info
*) p1
;
2955 const struct case_info
*ci2
= (const struct case_info
*) p2
;
2956 int idx1
= ci1
->bb
->index
;
2957 int idx2
= ci2
->bb
->index
;
2961 else if (idx1
== idx2
)
2963 /* Make sure the default label is first in a group. */
2964 if (!CASE_LOW (ci1
->expr
))
2966 else if (!CASE_LOW (ci2
->expr
))
2969 return tree_int_cst_compare (CASE_LOW (ci1
->expr
),
2970 CASE_LOW (ci2
->expr
));
2976 /* Determine whether the outgoing edges of BB should receive an
2977 ASSERT_EXPR for each of the operands of BB's LAST statement.
2978 The last statement of BB must be a SWITCH_EXPR.
2980 If any of the sub-graphs rooted at BB have an interesting use of
2981 the predicate operands, an assert location node is added to the
2982 list of assertions for the corresponding operands. */
2985 vrp_asserts::find_switch_asserts (basic_block bb
, gswitch
*last
)
2987 gimple_stmt_iterator bsi
;
2990 struct case_info
*ci
;
2991 size_t n
= gimple_switch_num_labels (last
);
2992 #if GCC_VERSION >= 4000
2995 /* Work around GCC 3.4 bug (PR 37086). */
2996 volatile unsigned int idx
;
2999 bsi
= gsi_for_stmt (last
);
3000 op
= gimple_switch_index (last
);
3001 if (TREE_CODE (op
) != SSA_NAME
)
3004 /* Build a vector of case labels sorted by destination label. */
3005 ci
= XNEWVEC (struct case_info
, n
);
3006 for (idx
= 0; idx
< n
; ++idx
)
3008 ci
[idx
].expr
= gimple_switch_label (last
, idx
);
3009 ci
[idx
].bb
= label_to_block (fun
, CASE_LABEL (ci
[idx
].expr
));
3011 edge default_edge
= find_edge (bb
, ci
[0].bb
);
3012 qsort (ci
, n
, sizeof (struct case_info
), compare_case_labels
);
3014 for (idx
= 0; idx
< n
; ++idx
)
3017 tree cl
= ci
[idx
].expr
;
3018 basic_block cbb
= ci
[idx
].bb
;
3020 min
= CASE_LOW (cl
);
3021 max
= CASE_HIGH (cl
);
3023 /* If there are multiple case labels with the same destination
3024 we need to combine them to a single value range for the edge. */
3025 if (idx
+ 1 < n
&& cbb
== ci
[idx
+ 1].bb
)
3027 /* Skip labels until the last of the group. */
3030 } while (idx
< n
&& cbb
== ci
[idx
].bb
);
3033 /* Pick up the maximum of the case label range. */
3034 if (CASE_HIGH (ci
[idx
].expr
))
3035 max
= CASE_HIGH (ci
[idx
].expr
);
3037 max
= CASE_LOW (ci
[idx
].expr
);
3040 /* Can't extract a useful assertion out of a range that includes the
3042 if (min
== NULL_TREE
)
3045 /* Find the edge to register the assert expr on. */
3046 e
= find_edge (bb
, cbb
);
3048 /* Register the necessary assertions for the operand in the
3050 auto_vec
<assert_info
, 8> asserts
;
3051 register_edge_assert_for (op
, e
,
3052 max
? GE_EXPR
: EQ_EXPR
,
3053 op
, fold_convert (TREE_TYPE (op
), min
),
3056 register_edge_assert_for (op
, e
, LE_EXPR
, op
,
3057 fold_convert (TREE_TYPE (op
), max
),
3059 finish_register_edge_assert_for (e
, bsi
, asserts
);
3064 if (!live
.live_on_edge_p (op
, default_edge
))
3067 /* Now register along the default label assertions that correspond to the
3068 anti-range of each label. */
3069 int insertion_limit
= param_max_vrp_switch_assertions
;
3070 if (insertion_limit
== 0)
3073 /* We can't do this if the default case shares a label with another case. */
3074 tree default_cl
= gimple_switch_default_label (last
);
3075 for (idx
= 1; idx
< n
; idx
++)
3078 tree cl
= gimple_switch_label (last
, idx
);
3079 if (CASE_LABEL (cl
) == CASE_LABEL (default_cl
))
3082 min
= CASE_LOW (cl
);
3083 max
= CASE_HIGH (cl
);
3085 /* Combine contiguous case ranges to reduce the number of assertions
3087 for (idx
= idx
+ 1; idx
< n
; idx
++)
3089 tree next_min
, next_max
;
3090 tree next_cl
= gimple_switch_label (last
, idx
);
3091 if (CASE_LABEL (next_cl
) == CASE_LABEL (default_cl
))
3094 next_min
= CASE_LOW (next_cl
);
3095 next_max
= CASE_HIGH (next_cl
);
3097 wide_int difference
= (wi::to_wide (next_min
)
3098 - wi::to_wide (max
? max
: min
));
3099 if (wi::eq_p (difference
, 1))
3100 max
= next_max
? next_max
: next_min
;
3106 if (max
== NULL_TREE
)
3108 /* Register the assertion OP != MIN. */
3109 auto_vec
<assert_info
, 8> asserts
;
3110 min
= fold_convert (TREE_TYPE (op
), min
);
3111 register_edge_assert_for (op
, default_edge
, NE_EXPR
, op
, min
,
3113 finish_register_edge_assert_for (default_edge
, bsi
, asserts
);
3117 /* Register the assertion (unsigned)OP - MIN > (MAX - MIN),
3118 which will give OP the anti-range ~[MIN,MAX]. */
3119 tree uop
= fold_convert (unsigned_type_for (TREE_TYPE (op
)), op
);
3120 min
= fold_convert (TREE_TYPE (uop
), min
);
3121 max
= fold_convert (TREE_TYPE (uop
), max
);
3123 tree lhs
= fold_build2 (MINUS_EXPR
, TREE_TYPE (uop
), uop
, min
);
3124 tree rhs
= int_const_binop (MINUS_EXPR
, max
, min
);
3125 register_new_assert_for (op
, lhs
, GT_EXPR
, rhs
,
3126 NULL
, default_edge
, bsi
);
3129 if (--insertion_limit
== 0)
3134 /* Traverse all the statements in block BB looking for statements that
3135 may generate useful assertions for the SSA names in their operand.
3136 If a statement produces a useful assertion A for name N_i, then the
3137 list of assertions already generated for N_i is scanned to
3138 determine if A is actually needed.
3140 If N_i already had the assertion A at a location dominating the
3141 current location, then nothing needs to be done. Otherwise, the
3142 new location for A is recorded instead.
3144 1- For every statement S in BB, all the variables used by S are
3145 added to bitmap FOUND_IN_SUBGRAPH.
3147 2- If statement S uses an operand N in a way that exposes a known
3148 value range for N, then if N was not already generated by an
3149 ASSERT_EXPR, create a new assert location for N. For instance,
3150 if N is a pointer and the statement dereferences it, we can
3151 assume that N is not NULL.
3153 3- COND_EXPRs are a special case of #2. We can derive range
3154 information from the predicate but need to insert different
3155 ASSERT_EXPRs for each of the sub-graphs rooted at the
3156 conditional block. If the last statement of BB is a conditional
3157 expression of the form 'X op Y', then
3159 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
3161 b) If the conditional is the only entry point to the sub-graph
3162 corresponding to the THEN_CLAUSE, recurse into it. On
3163 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
3164 an ASSERT_EXPR is added for the corresponding variable.
3166 c) Repeat step (b) on the ELSE_CLAUSE.
3168 d) Mark X and Y in FOUND_IN_SUBGRAPH.
3177 In this case, an assertion on the THEN clause is useful to
3178 determine that 'a' is always 9 on that edge. However, an assertion
3179 on the ELSE clause would be unnecessary.
3181 4- If BB does not end in a conditional expression, then we recurse
3182 into BB's dominator children.
3184 At the end of the recursive traversal, every SSA name will have a
3185 list of locations where ASSERT_EXPRs should be added. When a new
3186 location for name N is found, it is registered by calling
3187 register_new_assert_for. That function keeps track of all the
3188 registered assertions to prevent adding unnecessary assertions.
3189 For instance, if a pointer P_4 is dereferenced more than once in a
3190 dominator tree, only the location dominating all the dereference of
3191 P_4 will receive an ASSERT_EXPR. */
3194 vrp_asserts::find_assert_locations_in_bb (basic_block bb
)
3198 last
= last_stmt (bb
);
3200 /* If BB's last statement is a conditional statement involving integer
3201 operands, determine if we need to add ASSERT_EXPRs. */
3203 && gimple_code (last
) == GIMPLE_COND
3204 && !fp_predicate (last
)
3205 && !ZERO_SSA_OPERANDS (last
, SSA_OP_USE
))
3206 find_conditional_asserts (bb
, as_a
<gcond
*> (last
));
3208 /* If BB's last statement is a switch statement involving integer
3209 operands, determine if we need to add ASSERT_EXPRs. */
3211 && gimple_code (last
) == GIMPLE_SWITCH
3212 && !ZERO_SSA_OPERANDS (last
, SSA_OP_USE
))
3213 find_switch_asserts (bb
, as_a
<gswitch
*> (last
));
3215 /* Traverse all the statements in BB marking used names and looking
3216 for statements that may infer assertions for their used operands. */
3217 for (gimple_stmt_iterator si
= gsi_last_bb (bb
); !gsi_end_p (si
);
3224 stmt
= gsi_stmt (si
);
3226 if (is_gimple_debug (stmt
))
3229 /* See if we can derive an assertion for any of STMT's operands. */
3230 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, i
, SSA_OP_USE
)
3233 enum tree_code comp_code
;
3235 /* If op is not live beyond this stmt, do not bother to insert
3237 if (!live
.live_on_block_p (op
, bb
))
3240 /* If OP is used in such a way that we can infer a value
3241 range for it, and we don't find a previous assertion for
3242 it, create a new assertion location node for OP. */
3243 if (infer_value_range (stmt
, op
, &comp_code
, &value
))
3245 /* If we are able to infer a nonzero value range for OP,
3246 then walk backwards through the use-def chain to see if OP
3247 was set via a typecast.
3249 If so, then we can also infer a nonzero value range
3250 for the operand of the NOP_EXPR. */
3251 if (comp_code
== NE_EXPR
&& integer_zerop (value
))
3254 gimple
*def_stmt
= SSA_NAME_DEF_STMT (t
);
3256 while (is_gimple_assign (def_stmt
)
3257 && CONVERT_EXPR_CODE_P
3258 (gimple_assign_rhs_code (def_stmt
))
3260 (gimple_assign_rhs1 (def_stmt
)) == SSA_NAME
3262 (TREE_TYPE (gimple_assign_rhs1 (def_stmt
))))
3264 t
= gimple_assign_rhs1 (def_stmt
);
3265 def_stmt
= SSA_NAME_DEF_STMT (t
);
3267 /* Note we want to register the assert for the
3268 operand of the NOP_EXPR after SI, not after the
3270 if (live
.live_on_block_p (t
, bb
))
3271 register_new_assert_for (t
, t
, comp_code
, value
,
3276 register_new_assert_for (op
, op
, comp_code
, value
, bb
, NULL
, si
);
3281 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, i
, SSA_OP_USE
)
3283 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, i
, SSA_OP_DEF
)
3284 live
.clear (op
, bb
);
3287 /* Traverse all PHI nodes in BB, updating live. */
3288 for (gphi_iterator si
= gsi_start_phis (bb
); !gsi_end_p (si
);
3291 use_operand_p arg_p
;
3293 gphi
*phi
= si
.phi ();
3294 tree res
= gimple_phi_result (phi
);
3296 if (virtual_operand_p (res
))
3299 FOR_EACH_PHI_ARG (arg_p
, phi
, i
, SSA_OP_USE
)
3301 tree arg
= USE_FROM_PTR (arg_p
);
3302 if (TREE_CODE (arg
) == SSA_NAME
)
3306 live
.clear (res
, bb
);
3310 /* Do an RPO walk over the function computing SSA name liveness
3311 on-the-fly and deciding on assert expressions to insert. */
3314 vrp_asserts::find_assert_locations (void)
3316 int *rpo
= XNEWVEC (int, last_basic_block_for_fn (fun
));
3317 int *bb_rpo
= XNEWVEC (int, last_basic_block_for_fn (fun
));
3318 int *last_rpo
= XCNEWVEC (int, last_basic_block_for_fn (fun
));
3321 rpo_cnt
= pre_and_rev_post_order_compute (NULL
, rpo
, false);
3322 for (i
= 0; i
< rpo_cnt
; ++i
)
3325 /* Pre-seed loop latch liveness from loop header PHI nodes. Due to
3326 the order we compute liveness and insert asserts we otherwise
3327 fail to insert asserts into the loop latch. */
3329 FOR_EACH_LOOP (loop
, 0)
3331 i
= loop
->latch
->index
;
3332 unsigned int j
= single_succ_edge (loop
->latch
)->dest_idx
;
3333 for (gphi_iterator gsi
= gsi_start_phis (loop
->header
);
3334 !gsi_end_p (gsi
); gsi_next (&gsi
))
3336 gphi
*phi
= gsi
.phi ();
3337 if (virtual_operand_p (gimple_phi_result (phi
)))
3339 tree arg
= gimple_phi_arg_def (phi
, j
);
3340 if (TREE_CODE (arg
) == SSA_NAME
)
3341 live
.set (arg
, loop
->latch
);
3345 for (i
= rpo_cnt
- 1; i
>= 0; --i
)
3347 basic_block bb
= BASIC_BLOCK_FOR_FN (fun
, rpo
[i
]);
3351 /* Process BB and update the live information with uses in
3353 find_assert_locations_in_bb (bb
);
3355 /* Merge liveness into the predecessor blocks and free it. */
3356 if (!live
.block_has_live_names_p (bb
))
3359 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3361 int pred
= e
->src
->index
;
3362 if ((e
->flags
& EDGE_DFS_BACK
) || pred
== ENTRY_BLOCK
)
3365 live
.merge (e
->src
, bb
);
3367 if (bb_rpo
[pred
] < pred_rpo
)
3368 pred_rpo
= bb_rpo
[pred
];
3371 /* Record the RPO number of the last visited block that needs
3372 live information from this block. */
3373 last_rpo
[rpo
[i
]] = pred_rpo
;
3376 live
.clear_block (bb
);
3378 /* We can free all successors live bitmaps if all their
3379 predecessors have been visited already. */
3380 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3381 if (last_rpo
[e
->dest
->index
] == i
)
3382 live
.clear_block (e
->dest
);
3386 XDELETEVEC (bb_rpo
);
3387 XDELETEVEC (last_rpo
);
3390 /* Create an ASSERT_EXPR for NAME and insert it in the location
3391 indicated by LOC. Return true if we made any edge insertions. */
3394 vrp_asserts::process_assert_insertions_for (tree name
, assert_locus
*loc
)
3396 /* Build the comparison expression NAME_i COMP_CODE VAL. */
3399 gimple
*assert_stmt
;
3403 /* If we have X <=> X do not insert an assert expr for that. */
3404 if (loc
->expr
== loc
->val
)
3407 cond
= build2 (loc
->comp_code
, boolean_type_node
, loc
->expr
, loc
->val
);
3408 assert_stmt
= build_assert_expr_for (cond
, name
);
3411 /* We have been asked to insert the assertion on an edge. This
3412 is used only by COND_EXPR and SWITCH_EXPR assertions. */
3413 gcc_checking_assert (gimple_code (gsi_stmt (loc
->si
)) == GIMPLE_COND
3414 || (gimple_code (gsi_stmt (loc
->si
))
3417 gsi_insert_on_edge (loc
->e
, assert_stmt
);
3421 /* If the stmt iterator points at the end then this is an insertion
3422 at the beginning of a block. */
3423 if (gsi_end_p (loc
->si
))
3425 gimple_stmt_iterator si
= gsi_after_labels (loc
->bb
);
3426 gsi_insert_before (&si
, assert_stmt
, GSI_SAME_STMT
);
3430 /* Otherwise, we can insert right after LOC->SI iff the
3431 statement must not be the last statement in the block. */
3432 stmt
= gsi_stmt (loc
->si
);
3433 if (!stmt_ends_bb_p (stmt
))
3435 gsi_insert_after (&loc
->si
, assert_stmt
, GSI_SAME_STMT
);
3439 /* If STMT must be the last statement in BB, we can only insert new
3440 assertions on the non-abnormal edge out of BB. Note that since
3441 STMT is not control flow, there may only be one non-abnormal/eh edge
3443 FOR_EACH_EDGE (e
, ei
, loc
->bb
->succs
)
3444 if (!(e
->flags
& (EDGE_ABNORMAL
|EDGE_EH
)))
3446 gsi_insert_on_edge (e
, assert_stmt
);
3453 /* Qsort helper for sorting assert locations. If stable is true, don't
3454 use iterative_hash_expr because it can be unstable for -fcompare-debug,
3455 on the other side some pointers might be NULL. */
3457 template <bool stable
>
3459 vrp_asserts::compare_assert_loc (const void *pa
, const void *pb
)
3461 assert_locus
* const a
= *(assert_locus
* const *)pa
;
3462 assert_locus
* const b
= *(assert_locus
* const *)pb
;
3464 /* If stable, some asserts might be optimized away already, sort
3474 if (a
->e
== NULL
&& b
->e
!= NULL
)
3476 else if (a
->e
!= NULL
&& b
->e
== NULL
)
3479 /* After the above checks, we know that (a->e == NULL) == (b->e == NULL),
3480 no need to test both a->e and b->e. */
3482 /* Sort after destination index. */
3485 else if (a
->e
->dest
->index
> b
->e
->dest
->index
)
3487 else if (a
->e
->dest
->index
< b
->e
->dest
->index
)
3490 /* Sort after comp_code. */
3491 if (a
->comp_code
> b
->comp_code
)
3493 else if (a
->comp_code
< b
->comp_code
)
3498 /* E.g. if a->val is ADDR_EXPR of a VAR_DECL, iterative_hash_expr
3499 uses DECL_UID of the VAR_DECL, so sorting might differ between
3500 -g and -g0. When doing the removal of redundant assert exprs
3501 and commonization to successors, this does not matter, but for
3502 the final sort needs to be stable. */
3510 ha
= iterative_hash_expr (a
->expr
, iterative_hash_expr (a
->val
, 0));
3511 hb
= iterative_hash_expr (b
->expr
, iterative_hash_expr (b
->val
, 0));
3514 /* Break the tie using hashing and source/bb index. */
3516 return (a
->e
!= NULL
3517 ? a
->e
->src
->index
- b
->e
->src
->index
3518 : a
->bb
->index
- b
->bb
->index
);
3519 return ha
> hb
? 1 : -1;
3522 /* Process all the insertions registered for every name N_i registered
3523 in NEED_ASSERT_FOR. The list of assertions to be inserted are
3524 found in ASSERTS_FOR[i]. */
3527 vrp_asserts::process_assert_insertions ()
3531 bool update_edges_p
= false;
3532 int num_asserts
= 0;
3534 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3537 EXECUTE_IF_SET_IN_BITMAP (need_assert_for
, 0, i
, bi
)
3539 assert_locus
*loc
= asserts_for
[i
];
3542 auto_vec
<assert_locus
*, 16> asserts
;
3543 for (; loc
; loc
= loc
->next
)
3544 asserts
.safe_push (loc
);
3545 asserts
.qsort (compare_assert_loc
<false>);
3547 /* Push down common asserts to successors and remove redundant ones. */
3549 assert_locus
*common
= NULL
;
3550 unsigned commonj
= 0;
3551 for (unsigned j
= 0; j
< asserts
.length (); ++j
)
3557 || loc
->e
->dest
!= common
->e
->dest
3558 || loc
->comp_code
!= common
->comp_code
3559 || ! operand_equal_p (loc
->val
, common
->val
, 0)
3560 || ! operand_equal_p (loc
->expr
, common
->expr
, 0))
3566 else if (loc
->e
== asserts
[j
-1]->e
)
3568 /* Remove duplicate asserts. */
3569 if (commonj
== j
- 1)
3574 free (asserts
[j
-1]);
3575 asserts
[j
-1] = NULL
;
3580 if (EDGE_COUNT (common
->e
->dest
->preds
) == ecnt
)
3582 /* We have the same assertion on all incoming edges of a BB.
3583 Insert it at the beginning of that block. */
3584 loc
->bb
= loc
->e
->dest
;
3586 loc
->si
= gsi_none ();
3588 /* Clear asserts commoned. */
3589 for (; commonj
!= j
; ++commonj
)
3590 if (asserts
[commonj
])
3592 free (asserts
[commonj
]);
3593 asserts
[commonj
] = NULL
;
3599 /* The asserts vector sorting above might be unstable for
3600 -fcompare-debug, sort again to ensure a stable sort. */
3601 asserts
.qsort (compare_assert_loc
<true>);
3602 for (unsigned j
= 0; j
< asserts
.length (); ++j
)
3607 update_edges_p
|= process_assert_insertions_for (ssa_name (i
), loc
);
3614 gsi_commit_edge_inserts ();
3616 statistics_counter_event (fun
, "Number of ASSERT_EXPR expressions inserted",
3620 /* Traverse the flowgraph looking for conditional jumps to insert range
3621 expressions. These range expressions are meant to provide information
3622 to optimizations that need to reason in terms of value ranges. They
3623 will not be expanded into RTL. For instance, given:
3632 this pass will transform the code into:
3638 x = ASSERT_EXPR <x, x < y>
3643 y = ASSERT_EXPR <y, x >= y>
3647 The idea is that once copy and constant propagation have run, other
3648 optimizations will be able to determine what ranges of values can 'x'
3649 take in different paths of the code, simply by checking the reaching
3650 definition of 'x'. */
3653 vrp_asserts::insert_range_assertions (void)
3655 need_assert_for
= BITMAP_ALLOC (NULL
);
3656 asserts_for
= XCNEWVEC (assert_locus
*, num_ssa_names
);
3658 calculate_dominance_info (CDI_DOMINATORS
);
3660 find_assert_locations ();
3661 if (!bitmap_empty_p (need_assert_for
))
3663 process_assert_insertions ();
3664 update_ssa (TODO_update_ssa_no_phi
);
3667 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3669 fprintf (dump_file
, "\nSSA form after inserting ASSERT_EXPRs\n");
3670 dump_function_to_file (current_function_decl
, dump_file
, dump_flags
);
3674 BITMAP_FREE (need_assert_for
);
3677 /* Return true if all imm uses of VAR are either in STMT, or
3678 feed (optionally through a chain of single imm uses) GIMPLE_COND
3679 in basic block COND_BB. */
3682 vrp_asserts::all_imm_uses_in_stmt_or_feed_cond (tree var
,
3684 basic_block cond_bb
)
3686 use_operand_p use_p
, use2_p
;
3687 imm_use_iterator iter
;
3689 FOR_EACH_IMM_USE_FAST (use_p
, iter
, var
)
3690 if (USE_STMT (use_p
) != stmt
)
3692 gimple
*use_stmt
= USE_STMT (use_p
), *use_stmt2
;
3693 if (is_gimple_debug (use_stmt
))
3695 while (is_gimple_assign (use_stmt
)
3696 && TREE_CODE (gimple_assign_lhs (use_stmt
)) == SSA_NAME
3697 && single_imm_use (gimple_assign_lhs (use_stmt
),
3698 &use2_p
, &use_stmt2
))
3699 use_stmt
= use_stmt2
;
3700 if (gimple_code (use_stmt
) != GIMPLE_COND
3701 || gimple_bb (use_stmt
) != cond_bb
)
3707 /* Convert range assertion expressions into the implied copies and
3708 copy propagate away the copies. Doing the trivial copy propagation
3709 here avoids the need to run the full copy propagation pass after
3712 FIXME, this will eventually lead to copy propagation removing the
3713 names that had useful range information attached to them. For
3714 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
3715 then N_i will have the range [3, +INF].
3717 However, by converting the assertion into the implied copy
3718 operation N_i = N_j, we will then copy-propagate N_j into the uses
3719 of N_i and lose the range information. We may want to hold on to
3720 ASSERT_EXPRs a little while longer as the ranges could be used in
3721 things like jump threading.
3723 The problem with keeping ASSERT_EXPRs around is that passes after
3724 VRP need to handle them appropriately.
3726 Another approach would be to make the range information a first
3727 class property of the SSA_NAME so that it can be queried from
3728 any pass. This is made somewhat more complex by the need for
3729 multiple ranges to be associated with one SSA_NAME. */
3732 vrp_asserts::remove_range_assertions ()
3735 gimple_stmt_iterator si
;
3736 /* 1 if looking at ASSERT_EXPRs immediately at the beginning of
3737 a basic block preceeded by GIMPLE_COND branching to it and
3738 __builtin_trap, -1 if not yet checked, 0 otherwise. */
3741 /* Note that the BSI iterator bump happens at the bottom of the
3742 loop and no bump is necessary if we're removing the statement
3743 referenced by the current BSI. */
3744 FOR_EACH_BB_FN (bb
, fun
)
3745 for (si
= gsi_after_labels (bb
), is_unreachable
= -1; !gsi_end_p (si
);)
3747 gimple
*stmt
= gsi_stmt (si
);
3749 if (is_gimple_assign (stmt
)
3750 && gimple_assign_rhs_code (stmt
) == ASSERT_EXPR
)
3752 tree lhs
= gimple_assign_lhs (stmt
);
3753 tree rhs
= gimple_assign_rhs1 (stmt
);
3756 var
= ASSERT_EXPR_VAR (rhs
);
3758 if (TREE_CODE (var
) == SSA_NAME
3759 && !POINTER_TYPE_P (TREE_TYPE (lhs
))
3760 && SSA_NAME_RANGE_INFO (lhs
))
3762 if (is_unreachable
== -1)
3765 if (single_pred_p (bb
)
3766 && assert_unreachable_fallthru_edge_p
3767 (single_pred_edge (bb
)))
3771 if (x_7 >= 10 && x_7 < 20)
3772 __builtin_unreachable ();
3773 x_8 = ASSERT_EXPR <x_7, ...>;
3774 if the only uses of x_7 are in the ASSERT_EXPR and
3775 in the condition. In that case, we can copy the
3776 range info from x_8 computed in this pass also
3779 && all_imm_uses_in_stmt_or_feed_cond (var
, stmt
,
3782 set_range_info (var
, SSA_NAME_RANGE_TYPE (lhs
),
3783 SSA_NAME_RANGE_INFO (lhs
)->get_min (),
3784 SSA_NAME_RANGE_INFO (lhs
)->get_max ());
3785 maybe_set_nonzero_bits (single_pred_edge (bb
), var
);
3789 /* Propagate the RHS into every use of the LHS. For SSA names
3790 also propagate abnormals as it merely restores the original
3791 IL in this case (an replace_uses_by would assert). */
3792 if (TREE_CODE (var
) == SSA_NAME
)
3794 imm_use_iterator iter
;
3795 use_operand_p use_p
;
3797 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
, lhs
)
3798 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
3799 SET_USE (use_p
, var
);
3802 replace_uses_by (lhs
, var
);
3804 /* And finally, remove the copy, it is not needed. */
3805 gsi_remove (&si
, true);
3806 release_defs (stmt
);
3810 if (!is_gimple_debug (gsi_stmt (si
)))
3817 class vrp_prop
: public ssa_propagation_engine
3820 vrp_prop (vr_values
*v
)
3821 : ssa_propagation_engine (),
3824 void initialize (struct function
*);
3828 enum ssa_prop_result
visit_stmt (gimple
*, edge
*, tree
*) FINAL OVERRIDE
;
3829 enum ssa_prop_result
visit_phi (gphi
*) FINAL OVERRIDE
;
3831 struct function
*fun
;
3832 vr_values
*m_vr_values
;
3835 /* Initialization required by ssa_propagate engine. */
3838 vrp_prop::initialize (struct function
*fn
)
3843 FOR_EACH_BB_FN (bb
, fun
)
3845 for (gphi_iterator si
= gsi_start_phis (bb
); !gsi_end_p (si
);
3848 gphi
*phi
= si
.phi ();
3849 if (!stmt_interesting_for_vrp (phi
))
3851 tree lhs
= PHI_RESULT (phi
);
3852 m_vr_values
->set_def_to_varying (lhs
);
3853 prop_set_simulate_again (phi
, false);
3856 prop_set_simulate_again (phi
, true);
3859 for (gimple_stmt_iterator si
= gsi_start_bb (bb
); !gsi_end_p (si
);
3862 gimple
*stmt
= gsi_stmt (si
);
3864 /* If the statement is a control insn, then we do not
3865 want to avoid simulating the statement once. Failure
3866 to do so means that those edges will never get added. */
3867 if (stmt_ends_bb_p (stmt
))
3868 prop_set_simulate_again (stmt
, true);
3869 else if (!stmt_interesting_for_vrp (stmt
))
3871 m_vr_values
->set_defs_to_varying (stmt
);
3872 prop_set_simulate_again (stmt
, false);
3875 prop_set_simulate_again (stmt
, true);
3880 /* Evaluate statement STMT. If the statement produces a useful range,
3881 return SSA_PROP_INTERESTING and record the SSA name with the
3882 interesting range into *OUTPUT_P.
3884 If STMT is a conditional branch and we can determine its truth
3885 value, the taken edge is recorded in *TAKEN_EDGE_P.
3887 If STMT produces a varying value, return SSA_PROP_VARYING. */
3889 enum ssa_prop_result
3890 vrp_prop::visit_stmt (gimple
*stmt
, edge
*taken_edge_p
, tree
*output_p
)
3892 tree lhs
= gimple_get_lhs (stmt
);
3893 value_range_equiv vr
;
3894 m_vr_values
->extract_range_from_stmt (stmt
, taken_edge_p
, output_p
, &vr
);
3898 if (m_vr_values
->update_value_range (*output_p
, &vr
))
3900 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3902 fprintf (dump_file
, "Found new range for ");
3903 print_generic_expr (dump_file
, *output_p
);
3904 fprintf (dump_file
, ": ");
3905 dump_value_range (dump_file
, &vr
);
3906 fprintf (dump_file
, "\n");
3909 if (vr
.varying_p ())
3910 return SSA_PROP_VARYING
;
3912 return SSA_PROP_INTERESTING
;
3914 return SSA_PROP_NOT_INTERESTING
;
3917 if (is_gimple_call (stmt
) && gimple_call_internal_p (stmt
))
3918 switch (gimple_call_internal_fn (stmt
))
3920 case IFN_ADD_OVERFLOW
:
3921 case IFN_SUB_OVERFLOW
:
3922 case IFN_MUL_OVERFLOW
:
3923 case IFN_ATOMIC_COMPARE_EXCHANGE
:
3924 /* These internal calls return _Complex integer type,
3925 which VRP does not track, but the immediate uses
3926 thereof might be interesting. */
3927 if (lhs
&& TREE_CODE (lhs
) == SSA_NAME
)
3929 imm_use_iterator iter
;
3930 use_operand_p use_p
;
3931 enum ssa_prop_result res
= SSA_PROP_VARYING
;
3933 m_vr_values
->set_def_to_varying (lhs
);
3935 FOR_EACH_IMM_USE_FAST (use_p
, iter
, lhs
)
3937 gimple
*use_stmt
= USE_STMT (use_p
);
3938 if (!is_gimple_assign (use_stmt
))
3940 enum tree_code rhs_code
= gimple_assign_rhs_code (use_stmt
);
3941 if (rhs_code
!= REALPART_EXPR
&& rhs_code
!= IMAGPART_EXPR
)
3943 tree rhs1
= gimple_assign_rhs1 (use_stmt
);
3944 tree use_lhs
= gimple_assign_lhs (use_stmt
);
3945 if (TREE_CODE (rhs1
) != rhs_code
3946 || TREE_OPERAND (rhs1
, 0) != lhs
3947 || TREE_CODE (use_lhs
) != SSA_NAME
3948 || !stmt_interesting_for_vrp (use_stmt
)
3949 || (!INTEGRAL_TYPE_P (TREE_TYPE (use_lhs
))
3950 || !TYPE_MIN_VALUE (TREE_TYPE (use_lhs
))
3951 || !TYPE_MAX_VALUE (TREE_TYPE (use_lhs
))))
3954 /* If there is a change in the value range for any of the
3955 REALPART_EXPR/IMAGPART_EXPR immediate uses, return
3956 SSA_PROP_INTERESTING. If there are any REALPART_EXPR
3957 or IMAGPART_EXPR immediate uses, but none of them have
3958 a change in their value ranges, return
3959 SSA_PROP_NOT_INTERESTING. If there are no
3960 {REAL,IMAG}PART_EXPR uses at all,
3961 return SSA_PROP_VARYING. */
3962 value_range_equiv new_vr
;
3963 m_vr_values
->extract_range_basic (&new_vr
, use_stmt
);
3964 const value_range_equiv
*old_vr
3965 = m_vr_values
->get_value_range (use_lhs
);
3966 if (!old_vr
->equal_p (new_vr
, /*ignore_equivs=*/false))
3967 res
= SSA_PROP_INTERESTING
;
3969 res
= SSA_PROP_NOT_INTERESTING
;
3970 new_vr
.equiv_clear ();
3971 if (res
== SSA_PROP_INTERESTING
)
3985 /* All other statements produce nothing of interest for VRP, so mark
3986 their outputs varying and prevent further simulation. */
3987 m_vr_values
->set_defs_to_varying (stmt
);
3989 return (*taken_edge_p
) ? SSA_PROP_INTERESTING
: SSA_PROP_VARYING
;
3992 /* Visit all arguments for PHI node PHI that flow through executable
3993 edges. If a valid value range can be derived from all the incoming
3994 value ranges, set a new range for the LHS of PHI. */
3996 enum ssa_prop_result
3997 vrp_prop::visit_phi (gphi
*phi
)
3999 tree lhs
= PHI_RESULT (phi
);
4000 value_range_equiv vr_result
;
4001 m_vr_values
->extract_range_from_phi_node (phi
, &vr_result
);
4002 if (m_vr_values
->update_value_range (lhs
, &vr_result
))
4004 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4006 fprintf (dump_file
, "Found new range for ");
4007 print_generic_expr (dump_file
, lhs
);
4008 fprintf (dump_file
, ": ");
4009 dump_value_range (dump_file
, &vr_result
);
4010 fprintf (dump_file
, "\n");
4013 if (vr_result
.varying_p ())
4014 return SSA_PROP_VARYING
;
4016 return SSA_PROP_INTERESTING
;
4019 /* Nothing changed, don't add outgoing edges. */
4020 return SSA_PROP_NOT_INTERESTING
;
4023 /* Traverse all the blocks folding conditionals with known ranges. */
4026 vrp_prop::finalize ()
4030 /* We have completed propagating through the lattice. */
4031 m_vr_values
->set_lattice_propagation_complete ();
4035 fprintf (dump_file
, "\nValue ranges after VRP:\n\n");
4036 m_vr_values
->dump_all_value_ranges (dump_file
);
4037 fprintf (dump_file
, "\n");
4040 /* Set value range to non pointer SSA_NAMEs. */
4041 for (i
= 0; i
< num_ssa_names
; i
++)
4043 tree name
= ssa_name (i
);
4047 const value_range_equiv
*vr
= m_vr_values
->get_value_range (name
);
4048 if (!name
|| !vr
->constant_p ())
4051 if (POINTER_TYPE_P (TREE_TYPE (name
))
4052 && range_includes_zero_p (vr
) == 0)
4053 set_ptr_nonnull (name
);
4054 else if (!POINTER_TYPE_P (TREE_TYPE (name
)))
4055 set_range_info (name
, *vr
);
4059 class vrp_folder
: public substitute_and_fold_engine
4062 vrp_folder (vr_values
*v
)
4063 : substitute_and_fold_engine (/* Fold all stmts. */ true),
4064 m_vr_values (v
), simplifier (v
)
4068 tree
value_of_expr (tree name
, gimple
*stmt
) OVERRIDE
4070 return m_vr_values
->value_of_expr (name
, stmt
);
4072 bool fold_stmt (gimple_stmt_iterator
*) FINAL OVERRIDE
;
4073 bool fold_predicate_in (gimple_stmt_iterator
*);
4075 vr_values
*m_vr_values
;
4076 simplify_using_ranges simplifier
;
4079 /* If the statement pointed by SI has a predicate whose value can be
4080 computed using the value range information computed by VRP, compute
4081 its value and return true. Otherwise, return false. */
4084 vrp_folder::fold_predicate_in (gimple_stmt_iterator
*si
)
4086 bool assignment_p
= false;
4088 gimple
*stmt
= gsi_stmt (*si
);
4090 if (is_gimple_assign (stmt
)
4091 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt
)) == tcc_comparison
)
4093 assignment_p
= true;
4094 val
= simplifier
.vrp_evaluate_conditional (gimple_assign_rhs_code (stmt
),
4095 gimple_assign_rhs1 (stmt
),
4096 gimple_assign_rhs2 (stmt
),
4099 else if (gcond
*cond_stmt
= dyn_cast
<gcond
*> (stmt
))
4100 val
= simplifier
.vrp_evaluate_conditional (gimple_cond_code (cond_stmt
),
4101 gimple_cond_lhs (cond_stmt
),
4102 gimple_cond_rhs (cond_stmt
),
4110 val
= fold_convert (gimple_expr_type (stmt
), val
);
4114 fprintf (dump_file
, "Folding predicate ");
4115 print_gimple_expr (dump_file
, stmt
, 0);
4116 fprintf (dump_file
, " to ");
4117 print_generic_expr (dump_file
, val
);
4118 fprintf (dump_file
, "\n");
4121 if (is_gimple_assign (stmt
))
4122 gimple_assign_set_rhs_from_tree (si
, val
);
4125 gcc_assert (gimple_code (stmt
) == GIMPLE_COND
);
4126 gcond
*cond_stmt
= as_a
<gcond
*> (stmt
);
4127 if (integer_zerop (val
))
4128 gimple_cond_make_false (cond_stmt
);
4129 else if (integer_onep (val
))
4130 gimple_cond_make_true (cond_stmt
);
4141 /* Callback for substitute_and_fold folding the stmt at *SI. */
4144 vrp_folder::fold_stmt (gimple_stmt_iterator
*si
)
4146 if (fold_predicate_in (si
))
4149 return simplifier
.simplify (si
);
4152 /* Blocks which have more than one predecessor and more than
4153 one successor present jump threading opportunities, i.e.,
4154 when the block is reached from a specific predecessor, we
4155 may be able to determine which of the outgoing edges will
4156 be traversed. When this optimization applies, we are able
4157 to avoid conditionals at runtime and we may expose secondary
4158 optimization opportunities.
4160 This class is effectively a driver for the generic jump
4161 threading code. It basically just presents the generic code
4162 with edges that may be suitable for jump threading.
4164 Unlike DOM, we do not iterate VRP if jump threading was successful.
4165 While iterating may expose new opportunities for VRP, it is expected
4166 those opportunities would be very limited and the compile time cost
4167 to expose those opportunities would be significant.
4169 As jump threading opportunities are discovered, they are registered
4170 for later realization. */
4172 class vrp_jump_threader
: public dom_walker
4175 vrp_jump_threader (struct function
*, vr_values
*);
4176 ~vrp_jump_threader ();
4178 void thread_jumps ()
4180 walk (m_fun
->cfg
->x_entry_block_ptr
);
4184 static tree
simplify_stmt (gimple
*stmt
, gimple
*within_stmt
,
4185 avail_exprs_stack
*, basic_block
);
4186 virtual edge
before_dom_children (basic_block
);
4187 virtual void after_dom_children (basic_block
);
4190 vr_values
*m_vr_values
;
4191 const_and_copies
*m_const_and_copies
;
4192 avail_exprs_stack
*m_avail_exprs_stack
;
4193 hash_table
<expr_elt_hasher
> *m_avail_exprs
;
4194 gcond
*m_dummy_cond
;
4197 vrp_jump_threader::vrp_jump_threader (struct function
*fun
, vr_values
*v
)
4198 : dom_walker (CDI_DOMINATORS
, REACHABLE_BLOCKS
)
4200 /* Ugh. When substituting values earlier in this pass we can wipe
4201 the dominance information. So rebuild the dominator information
4202 as we need it within the jump threading code. */
4203 calculate_dominance_info (CDI_DOMINATORS
);
4205 /* We do not allow VRP information to be used for jump threading
4206 across a back edge in the CFG. Otherwise it becomes too
4207 difficult to avoid eliminating loop exit tests. Of course
4208 EDGE_DFS_BACK is not accurate at this time so we have to
4210 mark_dfs_back_edges ();
4212 /* Allocate our unwinder stack to unwind any temporary equivalences
4213 that might be recorded. */
4214 m_const_and_copies
= new const_and_copies ();
4216 m_dummy_cond
= NULL
;
4219 m_avail_exprs
= new hash_table
<expr_elt_hasher
> (1024);
4220 m_avail_exprs_stack
= new avail_exprs_stack (m_avail_exprs
);
4223 vrp_jump_threader::~vrp_jump_threader ()
4225 /* We do not actually update the CFG or SSA graphs at this point as
4226 ASSERT_EXPRs are still in the IL and cfg cleanup code does not
4227 yet handle ASSERT_EXPRs gracefully. */
4228 delete m_const_and_copies
;
4229 delete m_avail_exprs
;
4230 delete m_avail_exprs_stack
;
4233 /* Called before processing dominator children of BB. We want to look
4234 at ASSERT_EXPRs and record information from them in the appropriate
4237 We could look at other statements here. It's not seen as likely
4238 to significantly increase the jump threads we discover. */
4241 vrp_jump_threader::before_dom_children (basic_block bb
)
4243 gimple_stmt_iterator gsi
;
4245 m_avail_exprs_stack
->push_marker ();
4246 m_const_and_copies
->push_marker ();
4247 for (gsi
= gsi_start_nondebug_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
4249 gimple
*stmt
= gsi_stmt (gsi
);
4250 if (gimple_assign_single_p (stmt
)
4251 && TREE_CODE (gimple_assign_rhs1 (stmt
)) == ASSERT_EXPR
)
4253 tree rhs1
= gimple_assign_rhs1 (stmt
);
4254 tree cond
= TREE_OPERAND (rhs1
, 1);
4255 tree inverted
= invert_truthvalue (cond
);
4256 vec
<cond_equivalence
> p
;
4258 record_conditions (&p
, cond
, inverted
);
4259 for (unsigned int i
= 0; i
< p
.length (); i
++)
4260 m_avail_exprs_stack
->record_cond (&p
[i
]);
4262 tree lhs
= gimple_assign_lhs (stmt
);
4263 m_const_and_copies
->record_const_or_copy (lhs
,
4264 TREE_OPERAND (rhs1
, 0));
4273 /* A trivial wrapper so that we can present the generic jump threading
4274 code with a simple API for simplifying statements. STMT is the
4275 statement we want to simplify, WITHIN_STMT provides the location
4276 for any overflow warnings.
4278 ?? This should be cleaned up. There's a virtually identical copy
4279 of this function in tree-ssa-dom.c. */
4282 vrp_jump_threader::simplify_stmt (gimple
*stmt
,
4283 gimple
*within_stmt
,
4284 avail_exprs_stack
*avail_exprs_stack
,
4287 /* First see if the conditional is in the hash table. */
4288 tree cached_lhs
= avail_exprs_stack
->lookup_avail_expr (stmt
, false, true);
4289 if (cached_lhs
&& is_gimple_min_invariant (cached_lhs
))
4292 class vr_values
*vr_values
= x_vr_values
;
4293 if (gcond
*cond_stmt
= dyn_cast
<gcond
*> (stmt
))
4295 tree op0
= gimple_cond_lhs (cond_stmt
);
4296 op0
= lhs_of_dominating_assert (op0
, bb
, stmt
);
4298 tree op1
= gimple_cond_rhs (cond_stmt
);
4299 op1
= lhs_of_dominating_assert (op1
, bb
, stmt
);
4301 simplify_using_ranges
simplifier (vr_values
);
4302 return simplifier
.vrp_evaluate_conditional (gimple_cond_code (cond_stmt
),
4303 op0
, op1
, within_stmt
);
4306 if (gswitch
*switch_stmt
= dyn_cast
<gswitch
*> (stmt
))
4308 tree op
= gimple_switch_index (switch_stmt
);
4309 if (TREE_CODE (op
) != SSA_NAME
)
4312 op
= lhs_of_dominating_assert (op
, bb
, stmt
);
4314 const value_range_equiv
*vr
= vr_values
->get_value_range (op
);
4315 return find_case_label_range (switch_stmt
, vr
);
4318 if (gassign
*assign_stmt
= dyn_cast
<gassign
*> (stmt
))
4320 tree lhs
= gimple_assign_lhs (assign_stmt
);
4321 if (TREE_CODE (lhs
) == SSA_NAME
4322 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
4323 || POINTER_TYPE_P (TREE_TYPE (lhs
)))
4324 && stmt_interesting_for_vrp (stmt
))
4328 value_range_equiv new_vr
;
4329 vr_values
->extract_range_from_stmt (stmt
, &dummy_e
,
4330 &dummy_tree
, &new_vr
);
4332 if (new_vr
.singleton_p (&singleton
))
4340 /* Called after processing dominator children of BB. This is where we
4341 actually call into the threader. */
4343 vrp_jump_threader::after_dom_children (basic_block bb
)
4346 m_dummy_cond
= gimple_build_cond (NE_EXPR
,
4347 integer_zero_node
, integer_zero_node
,
4350 x_vr_values
= m_vr_values
;
4351 thread_outgoing_edges (bb
, m_dummy_cond
, m_const_and_copies
,
4352 m_avail_exprs_stack
, NULL
,
4356 m_avail_exprs_stack
->pop_to_marker ();
4357 m_const_and_copies
->pop_to_marker ();
4360 /* STMT is a conditional at the end of a basic block.
4362 If the conditional is of the form SSA_NAME op constant and the SSA_NAME
4363 was set via a type conversion, try to replace the SSA_NAME with the RHS
4364 of the type conversion. Doing so makes the conversion dead which helps
4365 subsequent passes. */
4368 vrp_simplify_cond_using_ranges (vr_values
*query
, gcond
*stmt
)
4370 tree op0
= gimple_cond_lhs (stmt
);
4371 tree op1
= gimple_cond_rhs (stmt
);
4373 /* If we have a comparison of an SSA_NAME (OP0) against a constant,
4374 see if OP0 was set by a type conversion where the source of
4375 the conversion is another SSA_NAME with a range that fits
4376 into the range of OP0's type.
4378 If so, the conversion is redundant as the earlier SSA_NAME can be
4379 used for the comparison directly if we just massage the constant in the
4381 if (TREE_CODE (op0
) == SSA_NAME
4382 && TREE_CODE (op1
) == INTEGER_CST
)
4384 gimple
*def_stmt
= SSA_NAME_DEF_STMT (op0
);
4387 if (!is_gimple_assign (def_stmt
)
4388 || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt
)))
4391 innerop
= gimple_assign_rhs1 (def_stmt
);
4393 if (TREE_CODE (innerop
) == SSA_NAME
4394 && !POINTER_TYPE_P (TREE_TYPE (innerop
))
4395 && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (innerop
)
4396 && desired_pro_or_demotion_p (TREE_TYPE (innerop
), TREE_TYPE (op0
)))
4398 const value_range
*vr
= query
->get_value_range (innerop
);
4400 if (range_int_cst_p (vr
)
4401 && range_fits_type_p (vr
,
4402 TYPE_PRECISION (TREE_TYPE (op0
)),
4403 TYPE_SIGN (TREE_TYPE (op0
)))
4404 && int_fits_type_p (op1
, TREE_TYPE (innerop
)))
4406 tree newconst
= fold_convert (TREE_TYPE (innerop
), op1
);
4407 gimple_cond_set_lhs (stmt
, innerop
);
4408 gimple_cond_set_rhs (stmt
, newconst
);
4410 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4412 fprintf (dump_file
, "Folded into: ");
4413 print_gimple_stmt (dump_file
, stmt
, 0, TDF_SLIM
);
4414 fprintf (dump_file
, "\n");
4421 /* Main entry point to VRP (Value Range Propagation). This pass is
4422 loosely based on J. R. C. Patterson, ``Accurate Static Branch
4423 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
4424 Programming Language Design and Implementation, pp. 67-78, 1995.
4425 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
4427 This is essentially an SSA-CCP pass modified to deal with ranges
4428 instead of constants.
4430 While propagating ranges, we may find that two or more SSA name
4431 have equivalent, though distinct ranges. For instance,
4434 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
4436 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
4440 In the code above, pointer p_5 has range [q_2, q_2], but from the
4441 code we can also determine that p_5 cannot be NULL and, if q_2 had
4442 a non-varying range, p_5's range should also be compatible with it.
4444 These equivalences are created by two expressions: ASSERT_EXPR and
4445 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
4446 result of another assertion, then we can use the fact that p_5 and
4447 p_4 are equivalent when evaluating p_5's range.
4449 Together with value ranges, we also propagate these equivalences
4450 between names so that we can take advantage of information from
4451 multiple ranges when doing final replacement. Note that this
4452 equivalency relation is transitive but not symmetric.
4454 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
4455 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
4456 in contexts where that assertion does not hold (e.g., in line 6).
4458 TODO, the main difference between this pass and Patterson's is that
4459 we do not propagate edge probabilities. We only compute whether
4460 edges can be taken or not. That is, instead of having a spectrum
4461 of jump probabilities between 0 and 1, we only deal with 0, 1 and
4462 DON'T KNOW. In the future, it may be worthwhile to propagate
4463 probabilities to aid branch prediction. */
4466 execute_vrp (struct function
*fun
, bool warn_array_bounds_p
)
4468 loop_optimizer_init (LOOPS_NORMAL
| LOOPS_HAVE_RECORDED_EXITS
);
4469 rewrite_into_loop_closed_ssa (NULL
, TODO_update_ssa
);
4472 /* ??? This ends up using stale EDGE_DFS_BACK for liveness computation.
4473 Inserting assertions may split edges which will invalidate
4475 vrp_asserts
assert_engine (fun
);
4476 assert_engine
.insert_range_assertions ();
4478 threadedge_initialize_values ();
4480 /* For visiting PHI nodes we need EDGE_DFS_BACK computed. */
4481 mark_dfs_back_edges ();
4483 vr_values vrp_vr_values
;
4485 class vrp_prop
vrp_prop (&vrp_vr_values
);
4486 vrp_prop
.initialize (fun
);
4487 vrp_prop
.ssa_propagate ();
4489 /* Instantiate the folder here, so that edge cleanups happen at the
4490 end of this function. */
4491 vrp_folder
folder (&vrp_vr_values
);
4492 vrp_prop
.finalize ();
4494 /* If we're checking array refs, we want to merge information on
4495 the executability of each edge between vrp_folder and the
4496 check_array_bounds_dom_walker: each can clear the
4497 EDGE_EXECUTABLE flag on edges, in different ways.
4499 Hence, if we're going to call check_all_array_refs, set
4500 the flag on every edge now, rather than in
4501 check_array_bounds_dom_walker's ctor; vrp_folder may clear
4502 it from some edges. */
4503 if (warn_array_bounds
&& warn_array_bounds_p
)
4504 set_all_edges_as_executable (fun
);
4506 folder
.substitute_and_fold ();
4508 if (warn_array_bounds
&& warn_array_bounds_p
)
4510 array_bounds_checker
array_checker (fun
, &vrp_vr_values
);
4511 array_checker
.check ();
4514 /* We must identify jump threading opportunities before we release
4515 the datastructures built by VRP. */
4516 vrp_jump_threader
threader (fun
, &vrp_vr_values
);
4517 threader
.thread_jumps ();
4519 /* A comparison of an SSA_NAME against a constant where the SSA_NAME
4520 was set by a type conversion can often be rewritten to use the
4521 RHS of the type conversion.
4523 However, doing so inhibits jump threading through the comparison.
4524 So that transformation is not performed until after jump threading
4527 FOR_EACH_BB_FN (bb
, fun
)
4529 gimple
*last
= last_stmt (bb
);
4530 if (last
&& gimple_code (last
) == GIMPLE_COND
)
4531 vrp_simplify_cond_using_ranges (&vrp_vr_values
,
4532 as_a
<gcond
*> (last
));
4535 free_numbers_of_iterations_estimates (fun
);
4537 /* ASSERT_EXPRs must be removed before finalizing jump threads
4538 as finalizing jump threads calls the CFG cleanup code which
4539 does not properly handle ASSERT_EXPRs. */
4540 assert_engine
.remove_range_assertions ();
4542 /* If we exposed any new variables, go ahead and put them into
4543 SSA form now, before we handle jump threading. This simplifies
4544 interactions between rewriting of _DECL nodes into SSA form
4545 and rewriting SSA_NAME nodes into SSA form after block
4546 duplication and CFG manipulation. */
4547 update_ssa (TODO_update_ssa
);
4549 /* We identified all the jump threading opportunities earlier, but could
4550 not transform the CFG at that time. This routine transforms the
4551 CFG and arranges for the dominator tree to be rebuilt if necessary.
4553 Note the SSA graph update will occur during the normal TODO
4554 processing by the pass manager. */
4555 thread_through_all_blocks (false);
4557 threadedge_finalize_values ();
4560 loop_optimizer_finalize ();
4566 const pass_data pass_data_vrp
=
4568 GIMPLE_PASS
, /* type */
4570 OPTGROUP_NONE
, /* optinfo_flags */
4571 TV_TREE_VRP
, /* tv_id */
4572 PROP_ssa
, /* properties_required */
4573 0, /* properties_provided */
4574 0, /* properties_destroyed */
4575 0, /* todo_flags_start */
4576 ( TODO_cleanup_cfg
| TODO_update_ssa
), /* todo_flags_finish */
4579 class pass_vrp
: public gimple_opt_pass
4582 pass_vrp (gcc::context
*ctxt
)
4583 : gimple_opt_pass (pass_data_vrp
, ctxt
), warn_array_bounds_p (false)
4586 /* opt_pass methods: */
4587 opt_pass
* clone () { return new pass_vrp (m_ctxt
); }
4588 void set_pass_param (unsigned int n
, bool param
)
4590 gcc_assert (n
== 0);
4591 warn_array_bounds_p
= param
;
4593 virtual bool gate (function
*) { return flag_tree_vrp
!= 0; }
4594 virtual unsigned int execute (function
*fun
)
4595 { return execute_vrp (fun
, warn_array_bounds_p
); }
4598 bool warn_array_bounds_p
;
4599 }; // class pass_vrp
4604 make_pass_vrp (gcc::context
*ctxt
)
4606 return new pass_vrp (ctxt
);
4610 /* Worker for determine_value_range. */
4613 determine_value_range_1 (value_range
*vr
, tree expr
)
4615 if (BINARY_CLASS_P (expr
))
4617 value_range vr0
, vr1
;
4618 determine_value_range_1 (&vr0
, TREE_OPERAND (expr
, 0));
4619 determine_value_range_1 (&vr1
, TREE_OPERAND (expr
, 1));
4620 range_fold_binary_expr (vr
, TREE_CODE (expr
), TREE_TYPE (expr
),
4623 else if (UNARY_CLASS_P (expr
))
4626 determine_value_range_1 (&vr0
, TREE_OPERAND (expr
, 0));
4627 range_fold_unary_expr (vr
, TREE_CODE (expr
), TREE_TYPE (expr
),
4628 &vr0
, TREE_TYPE (TREE_OPERAND (expr
, 0)));
4630 else if (TREE_CODE (expr
) == INTEGER_CST
)
4634 value_range_kind kind
;
4636 /* For SSA names try to extract range info computed by VRP. Otherwise
4637 fall back to varying. */
4638 if (TREE_CODE (expr
) == SSA_NAME
4639 && INTEGRAL_TYPE_P (TREE_TYPE (expr
))
4640 && (kind
= get_range_info (expr
, &min
, &max
)) != VR_VARYING
)
4641 vr
->set (wide_int_to_tree (TREE_TYPE (expr
), min
),
4642 wide_int_to_tree (TREE_TYPE (expr
), max
),
4645 vr
->set_varying (TREE_TYPE (expr
));
4649 /* Compute a value-range for EXPR and set it in *MIN and *MAX. Return
4650 the determined range type. */
4653 determine_value_range (tree expr
, wide_int
*min
, wide_int
*max
)
4656 determine_value_range_1 (&vr
, expr
);
4657 if (vr
.constant_p ())
4659 *min
= wi::to_wide (vr
.min ());
4660 *max
= wi::to_wide (vr
.max ());