https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119785
--- Comment #10 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-13 branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:3abc678a266a5ae130b45591f09ba51618926001 commit r13-9607-g3abc678a266a5ae130b45591f09ba51618926001 Author: Jakub Jelinek <ja...@redhat.com> Date: Mon Apr 14 19:34:22 2025 +0200 expmed: Always use QImode for init_expmed set_zero_cost [PR119785] This is a regression on some targets introduced I believe by r6-2055 which added mode argument to set_src_cost. The problem here is that in the first iteration, mode is always QImode and we get as -Os zero cost set_src_cost (const0_rtx, QImode, false). But then we use the mode variable for iterating over int, partial int and vector int modes, so for the second iteration we call set_src_cost with mode which is at that time (machine_mode) (MAX_MODE_VECTOR_INT + 1). In the x86 case that happens to be V2HFmode and we don't crash (and compute the same 0 cost as we would for QImode). But e.g. in the SPARC case (machine_mode) (MAX_MODE_VECTOR_INT + 1) is MAX_MACHINE_MODE and that does all kinds of weird things especially when doing ubsan bootstrap. Fixed by always using QImode. 2025-04-14 Jakub Jelinek <ja...@redhat.com> PR rtl-optimization/119785 * expmed.cc (init_expmed): Always pass QImode rather than mode to set_src_cost passed to set_zero_cost. (cherry picked from commit f96a54350afcf7f3c90d0ecb51d7683d826acc00)
