[Bug target/126787] [15/16/17 Regression] i386: target clone on FMA4 emits wrong fma instruction with egpr

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126787

--- Comment #4 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-15 branch has been updated by Hongyu Wang
<[email protected]>:

https://gcc.gnu.org/g:68c97e6444b8478a45645348fcda43792448f4c2

commit r15-11495-g68c97e6444b8478a45645348fcda43792448f4c2
Author: Hongyu Wang <[email protected]>
Date:   Tue Aug 11 16:57:48 2026 +0800

    i386: Disallow APX EGPR in FMA4/XOP insns [PR target/126787]

    FMA4 and XOP instructions are VEX-only, so cannot be promoted to EVEX form.
    When enforcing -mapxf on such target clone, which is at --with-arch=native
    plus libgfortran bootstrap on Diamond Rapids or Nova Lake, the fma4 clone
    may generate unencodable vfmaddps with egpr in mem.

    Restrict all the FMA4/XOP patterns with replacing 'm' to 'jm' and add gpr16
    to the addr attribute to avoid egpr usage under high register pressure.

    gcc/ChangeLog:

            PR target/126787
            * config/i386/sse.md (*fma_fmadd_<mode>): Use the "jm" to replace
            "m" constraint and set addr attribute to "gpr16" for vex only
            alternatives.
            (*fma_fmsub_<mode>): Likewise.
            (*fma_fnmadd_<mode>): Likewise.
            (*fma_fnmsub_<mode>): Likewise.
            (*fma_fmaddsub_<mode>): Likewise.
            (*fma_fmsubadd_<mode>): Likewise.
            (xop_p<macs><ssemodesuffix><ssemodesuffix>): Likewise.
            (xop_p<macs>dql): Likewise.
            (xop_p<macs>dqh): Likewise.
            (xop_p<macs>wd): Likewise.
            (xop_p<madcs>wd): Likewise.
            (xop_pcmov_<mode><avxsizesuffix>): Likewise.
            (xop_phadd<u>bw): Likewise.
            (xop_phadd<u>bd): Likewise.
            (xop_phadd<u>bq): Likewise.
            (xop_phadd<u>wd): Likewise.
            (xop_phadd<u>wq): Likewise.
            (xop_phadd<u>dq): Likewise.
            (xop_phsubbw): Likewise.
            (xop_phsubwd): Likewise.
            (xop_phsubdq): Likewise.
            (xop_pperm): Likewise.
            (xop_pperm_pack_v2di_v4si): Likewise.
            (xop_pperm_pack_v4si_v8hi): Likewise.
            (xop_pperm_pack_v8hi_v16qi): Likewise.
            (xop_rotl<mode>3): Likewise.
            (xop_rotr<mode>3): Likewise.
            (xop_vrotl<mode>3): Likewise.
            (xop_sha<mode>3): Likewise.
            (xop_shl<mode>3): Likewise.
            (xop_frcz<mode>2): Likewise.
            (*xop_vmfrcz<mode>2): Likewise.
            (xop_maskcmp<mode>3): Likewise.
            (xop_maskcmp_uns<mode>3): Likewise.
            (xop_maskcmp_uns2<mode>3): Likewise.
            (xop_pcom_tf<mode>3): Likewise.
            (xop_vpermil2<mode>3): Likewise.

    gcc/testsuite/ChangeLog:

            PR target/126787
            * gcc.target/i386/pr126787.c: New test.

    (cherry picked from commit 475e9efffaf8de781d7e17b687faf1807e104b01)