https://gcc.gnu.org/g:157af9d1ea36bbece6f871bdbd7758471dfb4e8f
commit r16-9672-g157af9d1ea36bbece6f871bdbd7758471dfb4e8f Author: Richard Biener <[email protected]> Date: Tue Sep 15 10:52:22 2026 +0200 tree-optimization/127390 - vectorization of _BitInt comparisons We fail to reject vectorizing of comparisons of non-mode precision integer types. Those need to be dealt with via bitfield lowering in ifcvt or pattern recognition. PR tree-optimization/127390 * tree-vect-stmts.cc (vectorizable_comparison_1): Reject bit-precision integer comparisons. * gcc.dg/vect/vect-pr127390.c: New testcase. (cherry picked from commit faf5c056ca1826cffb5673fa3b445eb61a6bb7eb) Diff: --- gcc/testsuite/gcc.dg/vect/vect-pr127390.c | 29 +++++++++++++++++++++++++++++ gcc/tree-vect-stmts.cc | 7 +++++++ 2 files changed, 36 insertions(+) diff --git a/gcc/testsuite/gcc.dg/vect/vect-pr127390.c b/gcc/testsuite/gcc.dg/vect/vect-pr127390.c new file mode 100644 index 000000000000..05e0399ceba5 --- /dev/null +++ b/gcc/testsuite/gcc.dg/vect/vect-pr127390.c @@ -0,0 +1,29 @@ +/* { dg-additional-options "-O3" } */ +/* { dg-add-options vect_early_break } */ +/* { dg-require-effective-target vect_early_break_hw } */ +/* { dg-require-effective-target bitint } */ + +#include <stdint.h> +#include "tree-vect.h" + +typedef signed _BitInt(24) i24; +int8_t m0[2]; + +int __attribute__((noipa)) +foo (int16_t in2) +{ + int16_t x2; + int n = 0; + for (n = 0; n < 8; n++) { + if (((i24)(m0[1] ? m0[1] * 2 : 1) >= (i24)(x2 - 1))) break; + } + return n; +} + +int main(void) +{ + check_vect (); + if (foo (-1)) + __builtin_abort (); + return 0; +} diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc index 5a15952ea11d..34199449d169 100644 --- a/gcc/tree-vect-stmts.cc +++ b/gcc/tree-vect-stmts.cc @@ -12662,6 +12662,13 @@ vectorizable_comparison_1 (vec_info *vinfo, tree vectype, && (VECTOR_BOOLEAN_TYPE_P (vectype1) ^ VECTOR_BOOLEAN_TYPE_P (vectype2))) return false; + /* We cannot compare non-mode precision _BitInt types. Unlike bool + or bit-precision INTEGER_TYPE the padding bit values are target + dependent and possibly undefined. */ + if (TREE_CODE (TREE_TYPE (rhs1)) == BITINT_TYPE + && !type_has_mode_precision_p (TREE_TYPE (rhs1))) + return false; + /* Boolean values may have another representation in vectors and therefore we prefer bit operations over comparison for them (which also works for scalar masks). We store opcodes
