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[Bug target/27855] reassociation pass produces ~30% slower matrix multiplication code
- From: "ubizjak at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 2 Mar 2007 15:34:53 -0000
- Subject: [Bug target/27855] reassociation pass produces ~30% slower matrix multiplication code
- References: <bug-27855-1649@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #13 from ubizjak at gmail dot com 2007-03-02 15:34 -------
Any news about this problem?
Current mainline still has severe problems:
-msse3 -O2 -mfpmath=sse -ffast-math
GCC 4.3 -ffast-math double performance:
ALGORITHM NB REPS TIME MFLOPS
========= ===== ===== ========== ==========
atlasmm 60 1000 0.288 1499.91
-msse3 -O2 -mfpmath=sse
GCC 4.3 double performance:
ALGORITHM NB REPS TIME MFLOPS
========= ===== ===== ========== ==========
atlasmm 60 1000 0.192 2249.86
-msse3 -O2 -mfpmath=sse -ffast-math
GCC 4.3 -ffast-math single performance:
ALGORITHM NB REPS TIME MFLOPS
========= ===== ===== ========== ==========
atlasmm 60 1000 0.304 1420.96
-msse3 -O2 -mfpmath=sse
GCC 4.3 single performance:
ALGORITHM NB REPS TIME MFLOPS
========= ===== ===== ========== ==========
atlasmm 60 1000 0.172 2511.48
Please consider the fact that all benchmarks are using -ffast-math nowadays. ;)
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27855