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[Bug target/52572] suboptimal assignment to avx element
- From: "jakub at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 13 Mar 2012 07:54:14 +0000
- Subject: [Bug target/52572] suboptimal assignment to avx element
- Auto-submitted: auto-generated
- References: <bug-52572-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52572
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |jakub at gcc dot gnu.org
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-03-13 07:54:14 UTC ---
Have you actually tried that? Mixing VEX encoded insns with legacy encoded
SSE* insns is very costly, for good performance there needs to be a vzeroupper
in between (but then you lose the upper bits). See e.g. 2.8 in the AVX
Programming Reference.