[Bug target/112929] [14] RISC-V vector: Variable clobbered at runtime

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112929

--- Comment #21 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Pan Li <panli@gcc.gnu.org>:

https://gcc.gnu.org/g:ef21ae5c45f3b79a36fadc1cb5723c095e2965ad

commit r14-6490-gef21ae5c45f3b79a36fadc1cb5723c095e2965ad
Author: Juzhe-Zhong <juzhe.zhong@rivai.ai>
Date:   Wed Dec 13 13:48:11 2023 +0800

    RISC-V: Postpone full available optimization [VSETVL PASS]

    Fix VSETVL BUG that AVL is polluted

    .L15:
            li      a3,9
            lui     a4,%hi(s)
            sw      a3,%lo(j)(t2)
            sh      a5,%lo(s)(a4) <--a4 is hold the address of s
            beq     t0,zero,.L42
            sw      t5,8(t4)
            vsetvli zero,a4,e8,m8,ta,ma  <<--- a4 as avl

    Actually, this vsetvl is redundant.
    The root cause we include full available optimization in LCM local data
computation.

    full available optimization should be after LCM computation.

            PR target/112929
            PR target/112988

    gcc/ChangeLog:

            * config/riscv/riscv-vsetvl.cc
            (pre_vsetvl::compute_lcm_local_properties): Remove full available.
            (pre_vsetvl::pre_global_vsetvl_info): Add full available
optimization.

    gcc/testsuite/ChangeLog:

            * gcc.target/riscv/rvv/vsetvl/pr112929.c: New test.
            * gcc.target/riscv/rvv/vsetvl/pr112988.c: New test.