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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/96921] Failure to optimize combined boolean
 not patterns
Date: Wed, 28 Jul 2021 21:20:16 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D96921

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Hmm,  thinking about expanding this further:

int f1(int n)
{
    if (n&~63) __builtin_unreachable();
    return 63 - n;
}
int f2(int n)
{
    if (n&~63) __builtin_unreachable();
    return 63 ^ n;
}
These two should be able to get the same code which happens on clang alread=
y.

Something like (but with the expansion of the +!, etc.)
(simplify
 (minus INTEGER_CST@0 SSA_NAME@1)
 (if (exact_power2(@0 + 1) && get_nonzero_bits(@1) =3D=3D @0
  (bit_xor @1 @0)))=