[Bug target/110751] RISC-V: Suport undefined value that allows VSETVL PASS use TA/MA

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110751

--- Comment #42 from CVS 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:27282dc0931484c31fa391772499d878afcc746a

commit r14-4179-g27282dc0931484c31fa391772499d878afcc746a
Author: Juzhe-Zhong <juzhe.zh...@rivai.ai>
Date:   Wed Sep 20 22:58:49 2023 +0800

    internal-fn: Support undefined rtx for uninitialized SSA_NAME[PR110751]

    According to PR: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110751

    As Richard and Richi suggested, we recognize uninitialized SSA_NAME and
convert it
    into SCRATCH rtx if the target predicate allows SCRATCH.

    It can help to reduce redundant data move instructions of targets like
RISC-V.

    Bootstrap and Regression on x86 passed.

    gcc/ChangeLog:
            PR target/110751

            * internal-fn.cc (expand_fn_using_insn): Support undefined rtx
value.
            * optabs.cc (maybe_legitimize_operand): Ditto.
            (can_reuse_operands_p): Ditto.
            * optabs.h (enum expand_operand_type): Ditto.
            (create_undefined_input_operand): Ditto.