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| author | Jakub Jelinek <jakub@redhat.com> | 2022-06-16 14:36:04 +0200 |
|---|---|---|
| committer | Jakub Jelinek <jakub@redhat.com> | 2022-06-16 14:36:04 +0200 |
| commit | 74e6a40335765077e235269f19d2d9905d0d9e44 (patch) | |
| tree | ff4bd2c8879911ed600cae6471b90129599d2c96 /gcc/match.pd | |
| parent | 6a27c430468cb85454b19cef881a1422580657ff (diff) | |
| download | gcc-74e6a40335765077e235269f19d2d9905d0d9e44.zip gcc-74e6a40335765077e235269f19d2d9905d0d9e44.tar.gz gcc-74e6a40335765077e235269f19d2d9905d0d9e44.tar.bz2 | |
match.pd: Fix up __builtin_mul_overflow_p signed type optimization [PR105984]
Earlier in the simplification pattern, we require that @0 has compatible
type to the type of IMAGPART_EXPR, but for @1 which is a non-zero constant
all we require is that it the constant fits into that type.
Later the code checks if the constant is negative, because when min / max
values are divided by negative divisor, lo will be higher than hi.
In the following testcase, @1 has unsigned char type, while @0 has
int type, so @1 which is 254 is wi::neg_p and we were swapping lo and hi,
even when @1 cast to int isn't negative.
We could use tree_int_cst_sgn (@1) < 0 as the check instead and it would
work both for narrower types of @1 and even same or wider ones, but
I've noticed we probably don't want to call fold_convert (TREE_TYPE (@0), @1)
twice and when we save that result in a temporary, we can just use wi::neg_p
on that temporary.
2022-06-16 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/105984
* match.pd (__builtin_mul_overflow_p (x, cst, (stype) 0) ->
x > stype_max / cst || x < stype_min / cst): fold_convert @1
to TREE_TYPE (@0) just once and test for negative divisor
also on that folded constant instead of on @1.
* gcc.c-torture/execute/pr105984.c: New test.
Diffstat (limited to 'gcc/match.pd')
| -rw-r--r-- | gcc/match.pd | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/gcc/match.pd b/gcc/match.pd index c0aa3a2..ae5dc82 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -6076,16 +6076,15 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) (convert (eq @0 { TYPE_MIN_VALUE (TREE_TYPE (@0)); })) (with { + tree div = fold_convert (TREE_TYPE (@0), @1); tree lo = int_const_binop (TRUNC_DIV_EXPR, - TYPE_MIN_VALUE (TREE_TYPE (@0)), - fold_convert (TREE_TYPE (@0), @1)); + TYPE_MIN_VALUE (TREE_TYPE (@0)), div); tree hi = int_const_binop (TRUNC_DIV_EXPR, - TYPE_MAX_VALUE (TREE_TYPE (@0)), - fold_convert (TREE_TYPE (@0), @1)); + TYPE_MAX_VALUE (TREE_TYPE (@0)), div); tree etype = range_check_type (TREE_TYPE (@0)); if (etype) { - if (wi::neg_p (wi::to_wide (@1))) + if (wi::neg_p (wi::to_wide (div))) std::swap (lo, hi); lo = fold_convert (etype, lo); hi = fold_convert (etype, hi); |