https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117595
--- Comment #1 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jeff Law <l...@gcc.gnu.org>: https://gcc.gnu.org/g:f5ceca96278b2ffaff838216aa6644fedb603573 commit r15-5412-gf5ceca96278b2ffaff838216aa6644fedb603573 Author: Jeff Law <j...@ventanamicro.com> Date: Mon Nov 18 10:55:09 2024 -0700 [committed][RISC-V][PR target/117595] Fix bogus use of simplify_gen_subreg And stage3 begins... Zdenek's fuzzer caught this one. Essentially using simplify_gen_subreg directly with an offset of 0 when we just needed a lowpart. The offset of 0 works for little endian, but for big endian it's simply wrong. simplify_gen_subreg will return NULL_RTX because the case isn't representable. We then embed that NULL_RTX into an insn that's later scanned during mark_jump_label. Scanning the port I see a couple more instances of this incorrect idiom. One is pretty obvious to fix. The others look a bit goofy and I'll probably need to sync with Patrick on them. Anyway tested on riscv64-elf and riscv32-elf with no regressions. Pushing to the trunk. PR target/117595 gcc/ * config/riscv/sync.md (atomic_compare_and_swap<mode>): Use gen_lowpart rather than simplify_gen_subreg. * config/riscv/riscv.cc (riscv_legitimize_move): Similarly. gcc/testsuite/ * gcc.target/riscv/pr117595.c: New test.
