[Bug target/118357] risc-v xtheadvector did not handle the logic of vsetvl properly

[cvs-commit at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118357

--- Comment #4 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-14 branch has been updated by Kito Cheng <k...@gcc.gnu.org>:

https://gcc.gnu.org/g:e4586ae318436d63aa91c2d417f068987c77e442

commit r14-11548-ge4586ae318436d63aa91c2d417f068987c77e442
Author: Jin Ma <ji...@linux.alibaba.com>
Date:   Sat Jan 18 07:43:17 2025 -0700

    [PR target/118357] RISC-V: Disable fusing vsetvl instructions by
VSETVL_VTYPE_CHANGE_ONLY for XTheadVector.

    In RVV 1.0, the instruction "vsetvli    zero,zero,*" indicates that the
    available vector length (avl) does not change. However, in XTheadVector,
    this same instruction signifies that the avl should take the maximum value.
    Consequently, when fusing vsetvl instructions, the optimization labeled
    "VSETVL_VTYPE_CHANGE_ONLY" is disabled for XTheadVector.

            PR target/118357

    gcc/ChangeLog:

            * config/riscv/riscv-vsetvl.cc: Function change_vtype_only_p always
            returns false for XTheadVector.

    gcc/testsuite/ChangeLog:

            * gcc.target/riscv/rvv/xtheadvector/pr118357.c: New test.