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| author | Jakub Jelinek <jakub@redhat.com> | 2022-02-05 10:52:19 +0100 |
|---|---|---|
| committer | Jakub Jelinek <jakub@redhat.com> | 2022-02-05 10:53:54 +0100 |
| commit | b3763384a1f696260f3ee7bda8c0e7e4ad732ad9 (patch) | |
| tree | febcce6fffe8b8fa9fac9d643ba784416217f0b9 | |
| parent | affdeda16ef7fbd34f850443fe63bb407714297e (diff) | |
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match.pd: Fix x * 0.0 -> 0.0 folding [PR104389]
The recent PR95115 change to punt in const_binop on folding operation
with non-NaN operands into NaN if flag_trapping_math broke the following
testcase, because the x * 0.0 simplification punts just if
x maybe a NaN (because NaN * 0.0 is NaN not 0.0) or if one of the operands
could be negative zero. But Inf * 0.0 or -Inf * 0.0 is also NaN, not
0.0, so when NaNs are honored we need to punt for possible infinities too.
2022-02-05 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/104389
* match.pd (x * 0 -> 0): Punt if x maybe infinite and NaNs are
honored.
* gcc.dg/pr104389.c: New test.
| -rw-r--r-- | gcc/match.pd | 4 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/pr104389.c | 26 |
2 files changed, 29 insertions, 1 deletions
diff --git a/gcc/match.pd b/gcc/match.pd index 10ff867..7bbb801 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -256,10 +256,12 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) /* Maybe fold x * 0 to 0. The expressions aren't the same when x is NaN, since x * 0 is also NaN. Nor are they the same in modes with signed zeros, since multiplying a - negative value by 0 gives -0, not +0. */ + negative value by 0 gives -0, not +0. Nor when x is +-Inf, + since x * 0 is NaN. */ (simplify (mult @0 real_zerop@1) (if (!tree_expr_maybe_nan_p (@0) + && (!HONOR_NANS (type) || !tree_expr_maybe_infinite_p (@0)) && !tree_expr_maybe_real_minus_zero_p (@0) && !tree_expr_maybe_real_minus_zero_p (@1)) @1)) diff --git a/gcc/testsuite/gcc.dg/pr104389.c b/gcc/testsuite/gcc.dg/pr104389.c new file mode 100644 index 0000000..0c6c85a --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr104389.c @@ -0,0 +1,26 @@ +/* PR tree-optimization/104389 */ +/* { dg-do run } */ +/* { dg-options "-O2" } */ +/* { dg-add-options ieee } */ +/* { dg-require-effective-target inf } */ + +__attribute__((noipa)) double +foo (void) +{ + double a = __builtin_huge_val (); + return a * 0.0; +} + +__attribute__((noipa)) long double +bar (void) +{ + return __builtin_huge_vall () * 0.0L; +} + +int +main () +{ + if (!__builtin_isnan (foo ()) || !__builtin_isnanl (bar ())) + __builtin_abort (); + return 0; +} |