https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111313
--- Comment #1 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Pan Li <pa...@gcc.gnu.org>: https://gcc.gnu.org/g:572abb52f5761a647035ee39d0e443c1c3622e75 commit r14-3765-g572abb52f5761a647035ee39d0e443c1c3622e75 Author: Juzhe-Zhong <juzhe.zh...@rivai.ai> Date: Thu Sep 7 11:35:53 2023 +0800 RISC-V: Remove incorrect earliest vsetvl post optimization[PR111313] This patch removes the incorrect earliest poset vsetvl optimization, such bug was found in vect-double-reduc-5.c which is runtime(execution fail) and also in PR111313. For VLMAX intrinsics, we always emit a bogus patter which is vlmax_avl (see vector.md) to occupy a scalar register which is used by the following RVV instruction which is VLMAX AVL. Then for O2, O3, Ofast, earliest LCM works so well. However, for O1, the vlmax_avl is not well optimized in the before pass which confused LCM earliest so that we will end up with some redundant vsetvli zero,zero instructions in O1. (Note that O2 O3 Ofast are all good). To elide those redundant vsetvli zero,zero, I added cleanup_earliest_vsetvls to elide those redundant vsetvls. Now, after I review the implementation of this post optimizaiton again, I found it is incorrect and it is hard to do the post optimizations for vsetvls that earliest LCM failed to eliminate. Besides, such performance issues only happen in O1 or O0, such issues may not be serious. So remove it and we may will find another way (E.g. adjust vlmax_avl pattern COST) to optimize it if we really need to care about performance for O1. PR target/111313 gcc/ChangeLog: * config/riscv/riscv-vsetvl.cc (pass_vsetvl::cleanup_earliest_vsetvls): Remove. (pass_vsetvl::df_post_optimization): Remove incorrect function. gcc/testsuite/ChangeLog: * gcc.target/riscv/rvv/vsetvl/avl_single-13.c: Adapt test. * gcc.target/riscv/rvv/vsetvl/vlmax_bb_prop-17.c: Skip check for O1. * gcc.target/riscv/rvv/vsetvl/vlmax_bb_prop-18.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_bb_prop-19.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_bb_prop-20.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-1.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-10.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-11.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-12.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-13.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-14.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-15.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-16.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-17.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-18.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-19.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-2.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-20.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-21.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-22.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-23.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-24.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-25.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-26.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-27.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-28.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-3.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-4.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-5.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-6.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-7.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-8.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_phi-9.c: Ditto. * gcc.target/riscv/rvv/vsetvl/vlmax_switch_vtype-2.c: Ditto. * gcc.target/riscv/rvv/autovec/pr111313.c: New test.
