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[Bug target/38824] [4.4 regression] performance regression of sse code from 4.2/4.3
- From: "hubicka at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 15 Jan 2009 00:30:51 -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 #5 from hubicka at gcc dot gnu dot org 2009-01-15 00:30 -------
Created an attachment (id=17106)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=17106&action=view)
Proposed patch
The patch makes GCC to generate movaps load followed by addps. On Core 2 it
speeds up the testcase from 7s to 6.2s so I guess it works as expected.
The same however does not reproduce on AMD box and I am not sure if it is just
coincidence here or if really core preffer to split read-execute SSE operations
(it is not recommended by the manual).
H.J. perhaps, you can have some advice here? Or at least can we do some
benchmarking?
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38824