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[Bug tree-optimization/38328] Massive performance regression for jpeg_idct_islow
- From: "rguenth at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 30 Nov 2008 21:29:29 -0000
- Subject: [Bug tree-optimization/38328] Massive performance regression for jpeg_idct_islow
- References: <bug-38328-3483@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #10 from rguenth at gcc dot gnu dot org 2008-11-30 21:29 -------
"
/usr/lib/gcc-snapshot/libexec/gcc/i486-linux-gnu/4.4.0/cc1 -quiet -v -I.
-D_REENTRANT -DPIC ./jidctint.c -quiet -dumpbase jidctint.c -mtune=i486
-auxbase-strip .libs/jidctint.o -g -g -O2 -Wall -version -fPIC -o
/tmp/cc5hqg0m.s
"
so it uses -mtune=i486 - this optimizes the multiplication for i486 where imul
is slow. The difference to 4.3 is a packaging issue in Debian.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |INVALID
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38328