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From: "crazylht at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug target/101456] Unnecessary vzeroupper when upper bits of YMM
 registers already zero
Date: Wed, 16 Feb 2022 04:57:49 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D101456

--- Comment #9 from Hongtao.liu <crazylht at gmail dot com> ---
(In reply to H.J. Lu from comment #8)
> It turns out that reading YMM registers with all zero bits needs VZEROUPP=
ER
> on Sandy Bride, Ivy Bridge, Haswell, Broadwell and Alder Lake to avoid
> SSE <-> AVX transition penalty.

We should target tune for r12-2571-g9775e465c1fbfc32656de77c618c61acf5bd905=
d.=