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[Bug target/53967] GCC produces slow code for convolution algorithm with -mfpmath=sse (the AMD_64 default)
- From: "bfriesen at simple dot dallas.tx.us" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Mon, 16 Jul 2012 15:35:03 +0000
- Subject: [Bug target/53967] GCC produces slow code for convolution algorithm with -mfpmath=sse (the AMD_64 default)
- Auto-submitted: auto-generated
- References: <bug-53967-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53967
--- Comment #10 from bfriesen at simple dot dallas.tx.us 2012-07-16 15:35:03 UTC ---
This particular application test was done with these options (i.e. -O2):
-m64 -mtune=generic -march=x86-64 -mfpmath=387 -O2
I have also tried -O3, with no positive benefit.
The Autoconf default is -O2 so that is what I generally test/tune the software
with. It is pretty rare to see additional benefit from -O3, although with some
versions of GCC I have seen application crashes due to wrong code from the tree
vectorizer.
Bob