https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120919
--- Comment #2 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:f5282f7402939fdec910ef3743d38edac864eec8 commit r16-1899-gf5282f7402939fdec910ef3743d38edac864eec8 Author: Jakub Jelinek <ja...@redhat.com> Date: Tue Jul 1 19:37:39 2025 +0200 testsuite: Fix up gcc.target/powerpc/builtin_altivec_tr_stxvr_runnable.c test (test UB) [PR120919] In my reading of the test and the instructions emitted by the builtins, it invokes UB 4 times, each time overwriting one byte after some variable (sc, then ss, then si and then sll). If we are lucky, like at -O0 -mcpu=power10, there is just padding there or something that doesn't make the tests fail, if unlucky like with -O0 -mcpu=power10 -fstack-protector-strong, &sc + 1 == &expected_sc and so it overwrites the expected_sc variable. The test fails when testing with RUNTESTFLAGS="--target_board=unix/'{,-fstack-protector-strong}'" on power10. The following patch fixes that by using arrays of 2 elements, so that the overwriting of 1 byte happens to the part of the same variable. 2025-07-01 Jakub Jelinek <ja...@redhat.com> PR testsuite/120919 * gcc.target/powerpc/builtin_altivec_tr_stxvr_runnable.c (main): Change sc, ss, si and sll vars from scalars to arrays of 2 elements, initialize and test just the first one though.
