[Bug target/104982] [12 Regression] FAIL: gcc.target/i386/bt-5.c by r12-7687

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104982

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

https://gcc.gnu.org/g:919fbffef0755562cd3b686c838069c20bc7878f

commit r12-7751-g919fbffef0755562cd3b686c838069c20bc7878f
Author: liuhongt <hongtao.liu@intel.com>
Date:   Mon Mar 21 20:54:30 2022 +0800

    Extend splitter pattern to reversed condition by swapping then and else
rtx. [PR target/104982]

    Failed to match this instruction:
    (set (reg/v:SI 88 [ z ])
        (if_then_else:SI (eq (zero_extract:SI (reg:SI 92)
                    (const_int 1 [0x1])
                    (zero_extend:SI (subreg:QI (reg:SI 93) 0)))
                (const_int 0 [0]))
            (reg:SI 95)
            (reg:SI 94)))

    but it's equal to

    (set (reg/v:SI 88 [ z ])
        (if_then_else:SI (ne (zero_extract:SI (reg:SI 92)
                    (const_int 1 [0x1])
                    (zero_extend:SI (subreg:QI (reg:SI 93) 0)))
                (const_int 0 [0]))
            (reg:SI 94)
            (reg:SI 95)))

    which is the exact existing splitter.

    The patch will fix below regressions:

    On x86-64, r12-7687 caused:

    FAIL: gcc.target/i386/bt-5.c scan-assembler-not sar[lq][ \t]
    FAIL: gcc.target/i386/bt-5.c scan-assembler-times bt[lq][ \t] 7

    gcc/ChangeLog:

            PR target/104982
            * config/i386/i386.md (*jcc_bt<mode>_mask): Extend the
            following splitter to reversed condition.