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[Bug target/41868] cell microcode instruction (addic.) is generated for a trivial loop with -O2 optimizations, hurting performance badly
- From: "siarhei dot siamashka at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 3 Nov 2009 20:09:30 -0000
- Subject: [Bug target/41868] cell microcode instruction (addic.) is generated for a trivial loop with -O2 optimizations, hurting performance badly
- References: <bug-41868-14457@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #7 from siarhei dot siamashka at gmail dot com 2009-11-03 20:09 -------
Thanks a lot for checking this. And sorry about the confusion caused by
attributing slowness of the testcase to the microcoded stuff (which turned out
to be not the case) without proper checking this first.
So should this bug be split into two? One about the incorrect warning, and
another one about generating nonoptimal code at -O2 level (extra load and store
operations, which are probably penalized by something like RAW hazard in such a
short loop)?
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41868