On Fri, Oct 02, 2026 at 05:10:25PM +1000, Yongqiang Tian wrote:
> GIMPLE_DEBUG statements currently consume UIDs and are then treated as
> non-assignments, which flushes pending VEC_PERM simplify sequences. This
> makes sequence blending depend on whether debug information is present.
>
> Skip debug statements before assigning UIDs and processing ordinary
> statements.
>
> Assisted-by: OpenAI Codex 5.6 Sol, co-reviewed by Claude and Yongqiang Tian.
>
> PR tree-optimization/127687
>
> gcc/ChangeLog:
>
> * tree-ssa-forwprop.cc (pass_forwprop::execute): Skip debug
> statements before assigning UIDs.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/pr127687.c: New test.
>
> Signed-off-by: Yongqiang Tian <[email protected]>
Committed now. Thanks.
Jakub
