https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82990
Bug ID: 82990
Summary: Add -mprefer-vzeroupper
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: hjl.tools at gmail dot com
CC: pavel.v.chupin at gmail dot com
Target Milestone: ---
Target: x86
Should we have a separate patch to add -mprefer-vzeroupper to cover all bases
in the future, like
/* opt_pass methods: */
virtual bool gate (function *)
{
return TARGET_AVX && (!TARGET_AVX512ER || TARGET_PREFER_VZEROUPPER)
&& TARGET_VZEROUPPER && flag_expensive_optimizations
&& !optimize_size;
}
Should explicit -mprefer-vzeroupper or -mno-prefer-vzeroupper override
whatever other optimization conditions there are (i.e. everything other than
TARGET_AVX and TARGET_VZEROUPPER)? I.e. use !TARGET_AVX512ER &&
flag_expensive_optimizations && !optimize_size only when the explicit bit is
not set for it?
