https://gcc.gnu.org/g:6868526bb79051895864a006c757ee5aee8e9574
commit r16-7111-g6868526bb79051895864a006c757ee5aee8e9574 Author: Richard Biener <[email protected]> Date: Wed Jan 28 10:04:45 2026 +0100 tree-optimization/123537 - fix too permissive .REDUC_* folding The following restricts the allowed conversions to those maintaining the element type size. PR tree-optimization/123537 * match.pd (REDUC (@0 & @1) -> @0[I] & @1[I]): Restrict allowed conversions. * gcc.dg/pr123537.c: New testcase. Diff: --- gcc/match.pd | 9 +++++---- gcc/testsuite/gcc.dg/pr123537.c | 20 ++++++++++++++++++++ 2 files changed, 25 insertions(+), 4 deletions(-) diff --git a/gcc/match.pd b/gcc/match.pd index e94e474bdc57..01b95ec07553 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -11415,10 +11415,11 @@ and, unsigned int elt_bits = tree_to_uhwi (TYPE_SIZE (elt_type)); tree size = bitsize_int (elt_bits); tree pos = bitsize_int (elt_bits * i); } - (view_convert - (bit_and:elt_type - (BIT_FIELD_REF:elt_type @0 { size; } { pos; }) - { elt; }))))))) + (if (compare_tree_int (TYPE_SIZE (type), elt_bits) == 0) + (view_convert + (bit_and:elt_type + (BIT_FIELD_REF:elt_type @0 { size; } { pos; }) + { elt; })))))))) /* Fold reduction of a single nonzero element constructor. */ (for reduc (IFN_REDUC_PLUS IFN_REDUC_IOR IFN_REDUC_XOR) diff --git a/gcc/testsuite/gcc.dg/pr123537.c b/gcc/testsuite/gcc.dg/pr123537.c new file mode 100644 index 000000000000..ff178358179e --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr123537.c @@ -0,0 +1,20 @@ +/* { dg-do compile } */ +/* { dg-require-effective-target int128 } */ +/* { dg-options "-O2" } */ + +typedef __attribute__((__vector_size__(16))) __int128 V; + +union { + _Complex long c; + V v; +} u; + +__int128 j; +int i; + +void +foo() +{ + u.v &= 4; + i %= u.c ? 3 : j; +}
