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[Bug rtl-optimization/21395] Performance degradation when building code that uses MMX intrinsics with gcc-4.0.0
- From: "ubizjak at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 23 Mar 2008 10:46:41 -0000
- Subject: [Bug rtl-optimization/21395] Performance degradation when building code that uses MMX intrinsics with gcc-4.0.0
- References: <bug-21395-10358@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #10 from ubizjak at gmail dot com 2008-03-23 10:46 -------
(In reply to comment #9)
> So on my duron 4.3 seems to beat 4.4 as i expected from the generated asm.
Can you tell from code dumps of 4.4 vs 4.3, where you think that 4.4 code is
worse than 4.3 for Duron? For Core2, 4.4 avoids store forwarding stall, but I'm
not sure why Duron prefers moves via memory instead of keeping values in %mm
registers.
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ubizjak at gmail dot com changed:
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21395