https://gcc.gnu.org/g:80c77d9a1cfbfde3a437361fa95be326fcdf3e58
commit r16-6752-g80c77d9a1cfbfde3a437361fa95be326fcdf3e58 Author: Andrew Pinski <[email protected]> Date: Mon Jan 12 18:58:47 2026 -0800 match: Add simplification of `(a*zero_one_valued_p) & b` if `a & b` simplifies [PR119402] This is a small reassociation for `a*bool & b` into `(a & b) * bool` checking if `a & b` simplifies. Since it could be the case `b` is `~a` or `a` or something else that might simplify when anding with `a`. Note this fixes a regression for aarch64 where the cost of a multiply vs `&-` changed in GCC 14 and can no longer optimize some cases at the RTL level. Bootstrapped and tested on x86_64-linux-gnu. PR tree-optimization/119402 gcc/ChangeLog: * match.pd (`(a*zero_one_valued_p) & b`): New pattern. gcc/testsuite/ChangeLog: * gcc.dg/tree-ssa/bitops-14.c: New test. * gcc.dg/tree-ssa/bitops-15.c: New test. Signed-off-by: Andrew Pinski <[email protected]> Diff: --- gcc/match.pd | 5 +++++ gcc/testsuite/gcc.dg/tree-ssa/bitops-14.c | 24 ++++++++++++++++++++++++ gcc/testsuite/gcc.dg/tree-ssa/bitops-15.c | 24 ++++++++++++++++++++++++ 3 files changed, 53 insertions(+) diff --git a/gcc/match.pd b/gcc/match.pd index cc33a972b982..2be1c5d83f1a 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -5137,6 +5137,11 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) && (GIMPLE || !TREE_SIDE_EFFECTS (@1))) (cond (convert:boolean_type_node @2) @1 @0))) +/* Transform A & (B*cmp) into (A&B)*cmp. */ +(simplify + (bit_and:c (mult:cs zero_one_valued_p@0 @1) @2) + (mult @0 (bit_and! @1 @2))) + /* (x <= 0 ? -x : 0) -> max(-x, 0). */ (simplify (cond (le @0 integer_zerop@1) (negate@2 @0) integer_zerop@1) diff --git a/gcc/testsuite/gcc.dg/tree-ssa/bitops-14.c b/gcc/testsuite/gcc.dg/tree-ssa/bitops-14.c new file mode 100644 index 000000000000..4fe794672871 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/bitops-14.c @@ -0,0 +1,24 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-optimized" } */ + + +__attribute__((noipa)) +int x(_Bool iftmp, unsigned _6) +{ + return ((-iftmp) & _6) & (~_6); +} +__attribute__((noipa)) +int y(_Bool iftmp, unsigned _6) +{ + return (iftmp * _6) & (~_6); +} +__attribute__((noipa)) +int z(_Bool iftmp, unsigned _6) +{ + unsigned t = ~_6; + unsigned t1 = (iftmp ? _6 : 0); + return t1 & t; +} + +/* In this case AND should be removed. */ +/* { dg-final { scan-tree-dump-not " & " "optimized" } } */ diff --git a/gcc/testsuite/gcc.dg/tree-ssa/bitops-15.c b/gcc/testsuite/gcc.dg/tree-ssa/bitops-15.c new file mode 100644 index 000000000000..37608bb35f0d --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/bitops-15.c @@ -0,0 +1,24 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-optimized" } */ + + +__attribute__((noipa)) +int x(_Bool iftmp, unsigned _6) +{ + return ((-iftmp) & _6) & (_6); +} +__attribute__((noipa)) +int y(_Bool iftmp, unsigned _6) +{ + return (iftmp * _6) & (_6); +} +__attribute__((noipa)) +int z(_Bool iftmp, unsigned _6) +{ + unsigned t = _6; + unsigned t1 = (iftmp ? _6 : 0); + return t1 & t; +} + +/* In this case AND should be removed. */ +/* { dg-final { scan-tree-dump-not " & " "optimized" } } */
