[Bug target/111657] Memory copy with structure assignment from named address space should be improved

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111657

--- Comment #12 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Uros Bizjak <u...@gcc.gnu.org>:

https://gcc.gnu.org/g:aa29654b1128a572c97fcaba94095f493662a0db

commit r16-276-gaa29654b1128a572c97fcaba94095f493662a0db
Author: Uros Bizjak <ubiz...@gmail.com>
Date:   Tue Apr 29 10:25:45 2025 +0200

    i386: Allow string instructions from non-default address space [PR111657]

    MOVS instructions allow segment override of their source operand, e.g.:

            rep movsq %gs:(%rsi), (%rdi)

    where %rsi is the address of the source location (with %gs segment
override)
    and %rdi is the address of the destination location.

    The testcase improves from (-O2 -mno-sse -mtune=generic):

            xorl    %eax, %eax
    .L2:
            movl    %eax, %edx
            addl    $8, %eax
            movq    %gs:m(%rdx), %rcx
            movq    %rcx, (%rdi,%rdx)
            cmpl    $240, %eax
            jb      .L2
            ret

    to:
            movl    $m, %esi
            movl    $30, %ecx
            rep movsq %gs:(%rsi), (%rdi)
            ret

            PR target/111657

    gcc/ChangeLog:

            * config/i386/i386-expand.cc (alg_usable_p): Remove have_as bool
            argument and add dst_as and src_as address space arguments.  Reject
            libcall algorithm with dst_as and src_as in the non-default address
            spaces.  Reject rep_prefix_{1,4,8}_byte algorithms with dst_as in
            the non-default address space.
            (decide_alg): Remove have_as bool argument and add dst_as and
src_as
            address space arguments.  Update calls to alg_usable_p.
            (ix86_expand_set_or_cpymem): Update call to decide_alg.
            * config/i386/i386.md (strmov): Do not fail if operand[3] (source)
            is in the non-default address space.  Expand with
gen_strmov_singleop
            only when operand[1] (destination) is in the default address space.
            (*strmovdi_rex_1): Determine memory operands from insn pattern.
            Allow only when destination is in the default address space.
            Rewrite asm template to use explicit operands.
            (*strmovsi_1): Ditto.
            (*strmovhi_1): DItto.
            (*strmovqi_1): Ditto.
            (*rep_movdi_rex64): Ditto.
            (*rep_movsi): Ditto.
            (*rep_movqi): Ditto.
            (*strsetdi_rex_1): Determine memory operands from insn pattern.
            Allow only when destination is in the default address space.
            (*strsetsi_1): Ditto.
            (*strsethi_1): Ditto.
            (*strsetqi_1): Ditto.
            (*rep_stosdi_rex64): Ditto.
            (*rep_stossi): Ditto.
            (*rep_stosqi): Ditto.

    gcc/testsuite/ChangeLog:

            * gcc.target/i386/pr111657-1.c: New test.