[Bug target/111252] LoongArch: Suboptimal code for (a & ~mask) | (b & mask) where mask is a constant with value ((1 << n) - 1) << m

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111252

--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Xi Ruoyao <xry111@gcc.gnu.org>:

https://gcc.gnu.org/g:5b857e87201335148f23ec7134cf7fbf97c04c72

commit r14-3773-g5b857e87201335148f23ec7134cf7fbf97c04c72
Author: Xi Ruoyao <xry111@xry111.site>
Date:   Tue Sep 5 19:42:30 2023 +0800

    LoongArch: Use bstrins instruction for (a & ~mask) and (a & mask) | (b &
~mask) [PR111252]

    If mask is a constant with value ((1 << N) - 1) << M we can perform this
    optimization.

    gcc/ChangeLog:

            PR target/111252
            * config/loongarch/loongarch-protos.h
            (loongarch_pre_reload_split): Declare new function.
            (loongarch_use_bstrins_for_ior_with_mask): Likewise.
            * config/loongarch/loongarch.cc
            (loongarch_pre_reload_split): Implement.
            (loongarch_use_bstrins_for_ior_with_mask): Likewise.
            * config/loongarch/predicates.md (ins_zero_bitmask_operand):
            New predicate.
            * config/loongarch/loongarch.md (bstrins_<mode>_for_mask):
            New define_insn_and_split.
            (bstrins_<mode>_for_ior_mask): Likewise.
            (define_peephole2): Further optimize code sequence produced by
            bstrins_<mode>_for_ior_mask if possible.

    gcc/testsuite/ChangeLog:

            * g++.target/loongarch/bstrins-compile.C: New test.
            * g++.target/loongarch/bstrins-run.C: New test.