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[Bug target/38824] [4.4 Regression] performance regression of sse code from 4.2/4.3
- From: "bonzini at gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 9 Feb 2009 13:37:51 -0000
- Subject: [Bug target/38824] [4.4 Regression] performance regression of sse code from 4.2/4.3
- References: <bug-38824-12873@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #19 from bonzini at gnu dot org 2009-02-09 13:37 -------
Also, Dwarak, here the change is not from
addps (%rax, %rsi), %xmm1
to
movps (%rax, %rsi), %xmm0
addps %xmm0, %xmm1
but rather from
movps %xmm0, %xmm1
addps (%rax, %rsi), %xmm1
to the second snippet above. Does this pessimize on AMD too? I don't think
so, it should be 1 uop less, but I'd rather have confirmation.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38824