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From: Richard Biener <rguenth@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org Subject: [gcc r13-1822] middle-end/106414 - fix mistake in ~(x ^ y) -> x == y pattern Date: Mon, 25 Jul 2022 11:25:02 +0000 (GMT) [thread overview] Message-ID: <20220725112502.A96FE3857B8A@sourceware.org> (raw) https://gcc.gnu.org/g:613e3b86955ea3b4977490625328708e82bea6fa commit r13-1822-g613e3b86955ea3b4977490625328708e82bea6fa Author: Richard Biener <rguenther@suse.de> Date: Mon Jul 25 12:10:48 2022 +0200 middle-end/106414 - fix mistake in ~(x ^ y) -> x == y pattern When compares are integer typed the inversion with ~ isn't properly preserved by the equality comparison even when converting the result properly. The following fixes this by restricting the input precisions accordingly. PR middle-end/106414 * match.pd (~(x ^ y) -> x == y): Restrict to single bit precision types. * gcc.dg/torture/pr106414-1.c: New testcase. * gcc.dg/torture/pr106414-2.c: Likewise. Diff: --- gcc/match.pd | 3 ++- gcc/testsuite/gcc.dg/torture/pr106414-1.c | 12 ++++++++++++ gcc/testsuite/gcc.dg/torture/pr106414-2.c | 12 ++++++++++++ 3 files changed, 26 insertions(+), 1 deletion(-) diff --git a/gcc/match.pd b/gcc/match.pd index 9736393061a..330c1db0c8e 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -1946,7 +1946,8 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) /* ~(a ^ b) is a == b for truth valued a and b. */ (simplify (bit_not (bit_xor:s truth_valued_p@0 truth_valued_p@1)) - (if (!VECTOR_TYPE_P (type)) + (if (INTEGRAL_TYPE_P (TREE_TYPE (@0)) + && TYPE_PRECISION (TREE_TYPE (@0)) == 1) (convert (eq @0 @1)))) /* (x & ~m) | (y & m) -> ((x ^ y) & m) ^ x */ diff --git a/gcc/testsuite/gcc.dg/torture/pr106414-1.c b/gcc/testsuite/gcc.dg/torture/pr106414-1.c new file mode 100644 index 00000000000..097471617b4 --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr106414-1.c @@ -0,0 +1,12 @@ +/* { dg-do run } */ + +int a, c, e; +const int b = 1; +char d; +int main() { + a = ~(e || 0) ^ b & ~d; + d = ~(a | ~2); + if (d) + __builtin_abort(); + return 0; +} diff --git a/gcc/testsuite/gcc.dg/torture/pr106414-2.c b/gcc/testsuite/gcc.dg/torture/pr106414-2.c new file mode 100644 index 00000000000..bed6a40c61e --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr106414-2.c @@ -0,0 +1,12 @@ +/* { dg-do run } */ + +int a, b, c, d; +unsigned e; +int main() { + c = e = -((a && 1) ^ ~(b || 0)); + if (e < -1) + d = c; + if (!d) + __builtin_abort(); + return 0; +}
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