> Am 22.07.2022 um 22:17 schrieb H.J. Lu via Gcc-patches > <gcc-patches@gcc.gnu.org>: > > On Thu, Jul 21, 2022 at 4:24 AM Richard Biener via Gcc-patches > <gcc-patches@gcc.gnu.org> wrote: >> >> The following makes sure to fold ~(a ^ b) to a == b for truth >> values (but not vectors, we'd have to check for vector support of >> equality). That turns the PR106379 testcase into a ranger one. >> >> Note that while we arrive at ~(a ^ b) in a convoluted way from >> original !a == !b one can eventually write the expression this >> way directly as well. >> >> Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed. >> >> PR tree-optimization/106379 >> * match.pd (~(a ^ b) -> a == b): New pattern. >> >> * gcc.dg/pr106379-1.c: New testcase. >> --- >> gcc/match.pd | 6 ++++++ >> gcc/testsuite/gcc.dg/pr106379-1.c | 9 +++++++++ >> 2 files changed, 15 insertions(+) >> create mode 100644 gcc/testsuite/gcc.dg/pr106379-1.c >> >> diff --git a/gcc/match.pd b/gcc/match.pd >> index 8bbc0dbd5cd..88a1a5aa9cc 100644 >> --- a/gcc/match.pd >> +++ b/gcc/match.pd >> @@ -1938,6 +1938,12 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) >> (if (tree_nop_conversion_p (type, TREE_TYPE (@0))) >> (bit_not (bit_xor (view_convert @0) @1)))) >> >> +/* ~(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)) >> + (convert (eq @0 @1)))) > > For integers, isn't it wrong to convert ~(boolean exp) to boolean exp? That’s what the (convert. …) should compensate for? Richard > >> /* (x & ~m) | (y & m) -> ((x ^ y) & m) ^ x */ >> (simplify >> (bit_ior:c (bit_and:cs @0 (bit_not @2)) (bit_and:cs @1 @2)) >> diff --git a/gcc/testsuite/gcc.dg/pr106379-1.c >> b/gcc/testsuite/gcc.dg/pr106379-1.c >> new file mode 100644 >> index 00000000000..7f2575e02dc >> --- /dev/null >> +++ b/gcc/testsuite/gcc.dg/pr106379-1.c >> @@ -0,0 +1,9 @@ >> +/* { dg-do compile } */ >> +/* { dg-options "-O -fdump-tree-forwprop1" } */ >> + >> +_Bool foo (_Bool a, _Bool b) >> +{ >> + return !a == !b; >> +} >> + >> +/* { dg-final { scan-tree-dump "\[ab\]_\[0-9\]+\\(D\\) == >> \[ba\]_\[0-9\]+\\(D\\)" "forwprop1" } } */ >> -- >> 2.35.3 > > > > -- > H.J.
Re: [PATCH] tree-optimization/106379 - add missing ~(a ^ b) folding for _Bool
Richard Biener via Gcc-patches Fri, 22 Jul 2022 23:09:57 -0700
- [PATCH] tree-optimization/106379 - add miss... Richard Biener via Gcc-patches
- Re: [PATCH] tree-optimization/106379 -... H.J. Lu via Gcc-patches
- Re: [PATCH] tree-optimization/1063... Richard Biener via Gcc-patches
- Re: [PATCH] tree-optimization/... H.J. Lu via Gcc-patches
- Re: [PATCH] tree-optimizat... Richard Biener via Gcc-patches