diff options
| author | Jakub Jelinek <jakub@redhat.com> | 2020-05-08 09:32:20 +0200 |
|---|---|---|
| committer | Jakub Jelinek <jakub@redhat.com> | 2020-05-08 09:32:20 +0200 |
| commit | ff33680165346cb291667f38dd2e9f25a74cc3c3 (patch) | |
| tree | 357d4e2d6b76e6805659de387b7d161523eaceae /gcc/match.pd | |
| parent | af1634f1b555004753a22d1124dbb8419ee095cb (diff) | |
match.pd: Simplify unsigned A - B - 1 >= A to B >= A [PR94913]
Implemented thusly. The TYPE_OVERFLOW_WRAPS is there just because the
pattern above it has it too, if you want, I can throw it away from both.
2020-05-08 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/94913
* match.pd (A - B + -1 >= A to B >= A): New simplification.
(A - B > A to A < B): Don't test TYPE_OVERFLOW_WRAPS which is always
true for TYPE_UNSIGNED integral types.
* gcc.dg/tree-ssa/pr94913.c: New test.
Diffstat (limited to 'gcc/match.pd')
| -rw-r--r-- | gcc/match.pd | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/gcc/match.pd b/gcc/match.pd index 9259dd4ddaa..cfe96975d80 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -4787,10 +4787,17 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) (cmp:c (minus@2 @0 @1) @0) (if (single_use (@2) && ANY_INTEGRAL_TYPE_P (TREE_TYPE (@0)) - && TYPE_UNSIGNED (TREE_TYPE (@0)) - && TYPE_OVERFLOW_WRAPS (TREE_TYPE (@0))) + && TYPE_UNSIGNED (TREE_TYPE (@0))) (cmp @1 @0)))) +/* Optimize A - B + -1 >= A into B >= A for unsigned comparisons. */ +(for cmp (ge lt) + (simplify + (cmp:c (plus (minus @0 @1) integer_minus_onep) @0) + (if (ANY_INTEGRAL_TYPE_P (TREE_TYPE (@0)) + && TYPE_UNSIGNED (TREE_TYPE (@0))) + (cmp @1 @0)))) + /* Testing for overflow is unnecessary if we already know the result. */ /* A - B > A */ (for cmp (gt le) |