https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116149
--- Comment #4 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:f15cd1802129454029f7fcc8ee3ddd56a86cdad8 commit r15-2649-gf15cd1802129454029f7fcc8ee3ddd56a86cdad8 Author: Robin Dapp <rd...@ventanamicro.com> Date: Wed Jul 31 16:54:03 2024 +0200 RISC-V: Correct mode_idx attribute for viwalu wx variants [PR116149]. In PR116149 we choose a wrong vector length which causes wrong values in a reduction. The problem happens in avlprop where we choose the number of units in the instruction's mode as vector length. For the non-scalar variants the respective operand has the correct non-widened mode. For the scalar variants, however, the same operand has a scalar mode which obviously only has one unit. This makes us choose VL = 1 leaving three elements undisturbed (so potentially -1). Those end up in the reduction causing the wrong result. This patch adjusts the mode_idx just for the scalar variants of the affected instruction patterns. gcc/ChangeLog: PR target/116149 * config/riscv/vector.md: Fix mode_idx attribute of scalar widen add/sub variants. gcc/testsuite/ChangeLog: * gcc.target/riscv/rvv/autovec/pr116149.c: New test.
