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From: "crazylht at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/110202] _mm512_ternarylogic_epi64 generates
 unnecessary operations
Date: Wed, 28 Jun 2023 00:47:14 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D110202

--- Comment #8 from Hongtao.liu <crazylht at gmail dot com> ---
(In reply to Alexander Monakov from comment #7)
> Note that vpxor serves as a dependency-breaking instruction (see PR 11043=
8).
> So in negate1 we do the right thing for the wrong reasons, and in negate2=
 we
> can cause a substantial stall if the previous computation of xmm0 has a
> non-trivial dependency chain.

For this one, we can load *a into %zmm0 to avoid false_dependence.

vmovdqau ZMMWORD PTR [rdi], zmm0
vpternlogq      zmm0, zmm0, zmm0, 85=