https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117955
--- Comment #8 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Robin Dapp <rd...@gcc.gnu.org>: https://gcc.gnu.org/g:f043ef2b6a59088b16a269b55f09023f76c92e32 commit r15-8021-gf043ef2b6a59088b16a269b55f09023f76c92e32 Author: Robin Dapp <rd...@ventanamicro.com> Date: Tue Feb 25 12:55:08 2025 +0100 RISC-V: Adjust LMUL when using maximum SEW [PR117955]. When merging two vsetvls that both only demand "SEW >= ..." we use their maximum SEW and keep the LMUL. That may lead to invalid vector configurations like e64, mf4. As we make sure that the SEW requirements overlap we can use the SEW and LMUL of the configuration with the larger SEW. Ma Jin already touched this merge rule some weeks ago and fixed the ratio calculation (r15-6873). Calculating the ratio from an invalid SEW/LMUL combination lead to an overflow in the ratio variable, though. I'd argue the proper fix is to update SEW and LMUL, keeping the ratio as before. This "breaks" bug-10.c but its check only checked for a workaround anyway so I turned it into a run test. Ma Jin helped minify the PR's test and provided a larger test case for bug-10. PR target/117955 gcc/ChangeLog: * config/riscv/riscv-vsetvl.cc: Use LMUL/ratio from vsetvl with larger SEW. gcc/testsuite/ChangeLog: * gcc.target/riscv/rvv/base/bug-10.c: Convert to run test. * gcc.target/riscv/rvv/base/bug-10-2.c: New test. * gcc.target/riscv/rvv/base/pr117955.c: New test.
