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From: "qing.zhao at oracle dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug target/101891] Adjust -fzero-call-used-regs to always use XOR
Date: Tue, 24 May 2022 18:47:11 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D101891

--- Comment #8 from Qing Zhao <qing.zhao at oracle dot com> ---
> On May 24, 2022, at 11:42 AM, arjan at linux dot intel.com <gcc-bugzilla@=
gcc.gnu.org> wrote:
>=20
> --- Comment #7 from Arjan van de Ven <arjan at linux dot intel.com> ---
> from a performance angle, the xor-only sequence is not so great at all; m=
odern
> CPUs are really good at eliminating mov's so that's why the code original=
ly was
> added to do a combo of xor and mov..

Are you saying that the Xor-only sequence is slower than the previous XOR +=
 MOV
sequence?
If so, can you explain a little bit more on why? And do you have any data f=
or
this claim?

Thanks.=