https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121453
--- Comment #5 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:948f20cc520e50968f8759b173096358dcbba3de commit r16-3381-g948f20cc520e50968f8759b173096358dcbba3de Author: Jakub Jelinek <ja...@redhat.com> Date: Tue Aug 26 00:28:10 2025 +0200 omp-expand: Initialize fd->loop.n2 if needed for the zero iter case [PR121453] When expand_omp_for_init_counts is called from expand_omp_for_generic, zero_iter1_bb is NULL and the code always creates a new bb in which it clears fd->loop.n2 var (if it is a var), because it can dominate code with lastprivate guards that use the var. When called from other places, zero_iter1_bb is non-NULL and so we don't insert the clearing (and can't, because the same bb is used also for the non-zero iterations exit and in that case we need to preserve the iteration count). Clearing is also not necessary when e.g. outermost collapsed loop has constant non-zero number of iterations, in that case we initialize the var to something already earlier. The following patch makes sure to clear it if it hasn't been initialized yet before the first check for zero iterations. 2025-08-26 Jakub Jelinek <ja...@redhat.com> PR middle-end/121453 * omp-expand.cc (expand_omp_for_init_counts): Clear fd->loop.n2 before first zero count check if zero_iter1_bb is non-NULL upon entry and fd->loop.n2 has not been written yet. * gcc.dg/gomp/pr121453.c: New test.
