https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121334
--- Comment #4 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:980e1fc195325cd4637ce52d0e2b0e7fcc763f60 commit r16-3166-g980e1fc195325cd4637ce52d0e2b0e7fcc763f60 Author: Robin Dapp <rdapp....@gmail.com> Date: Mon Aug 4 11:09:50 2025 +0200 RISC-V: Expand const_vector with 2 elts per pattern. Hi, In PR121334 we are asked to expand a const_vector of size 4 with poly_int elements. It has 2 elts per pattern so is neither a const_vector_duplicate nor a const_vector_stepped. We don't allow this kind of constant in legitimate_constant_p but expr apparently still wants us to expand it under certain conditions. This patch implements a basic expander for such kinds of patterns. As slide1up is used to build the individual vectors it also adds a helper function expand_slide1up. I regtested on rv64gcv_zvl512b but unfortunately the newly created pattern is not even executed. I tried some variations of the original code but didn't manage to trigger it. Regards Robin PR target/121334 gcc/ChangeLog: * config/riscv/riscv-v.cc (expand_slide1up): New function. (expand_vector_init_trailing_same_elem): Use new function. (expand_const_vector_onestep): New function. (expand_const_vector): Uew expand_slide1up. (expand_vector_init_merge_repeating_sequence): Ditto. (shuffle_off_by_one_patterns): Ditto. gcc/testsuite/ChangeLog: * gcc.target/riscv/rvv/autovec/pr121334.c: New test.
