https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122749
Tamar Christina <tnfchris at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|[16 Regression] signed to |[16 Regression] signed to
|unsigned type conversions |unsigned type conversions
|inserted during |inserted during
|vectorization blocking MLA |vectorization blocking MLA
| |since r16-3328-g3182e95eda4
--- Comment #3 from Tamar Christina <tnfchris at gcc dot gnu.org> ---
Bisected to
commit 3182e95eda4a1d612b910b3248c997c8acc7add3
Author: Richard Biener <[email protected]>
Date: Thu Jan 23 14:29:26 2025 +0100
tree-optimization/111494 - reduction vectorization with signed UB
The following makes sure to pun arithmetic that's used in vectorized
reduction to unsigned when overflow invokes undefined behavior.
PR tree-optimization/111494
* gimple-fold.h (arith_code_with_undefined_signed_overflow):
Declare.
* gimple-fold.cc (arith_code_with_undefined_signed_overflow):
Export.
* tree-vect-stmts.cc (vectorizable_operation): Use unsigned
arithmetic for operations participating in a reduction.
gcc/gimple-fold.cc | 2 +-
gcc/gimple-fold.h | 1 +
gcc/tree-vect-stmts.cc | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 56 insertions(+), 1 deletion(-)
Will take a look after christmas.
