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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug tree-optimization/106243] Failure to optimize (0 - x) & 1 on
 gimple level (including vector types)
Date: Sun, 10 Jul 2022 20:29:20 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D106243

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|Failure to optimize (0 - x) |Failure to optimize (0 - x)
                   |& 1 on vector type          |& 1 on gimple level
                   |                            |(including vector types)
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2022-07-10
             Status|UNCONFIRMED                 |NEW

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed, even scalar version is not optimized on the gimple level:
int f1(int x)
{
    x =3D -x;
    return x & 1;
}


RTL level is done during combine for the scalar version:
Trying 6 -> 7:
    6: {r86:SI=3D-r87:SI;clobber flags:CC;}
      REG_DEAD r87:SI
      REG_UNUSED flags:CC
    7: {r85:SI=3Dr86:SI&0x1;clobber flags:CC;}
      REG_DEAD r86:SI
      REG_UNUSED flags:CC
Successfully matched this instruction:
(parallel [
        (set (reg:SI 85)
            (and:SI (reg:SI 87)
                (const_int 1 [0x1])))
        (clobber (reg:CC 17 flags))
    ])=