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[Bug fortran/20945] about 2x perfomance regression in comparision with 3.4.2
- From: "fxcoudert at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 19 Jun 2005 07:34:48 -0000
- Subject: [Bug fortran/20945] about 2x perfomance regression in comparision with 3.4.2
- References: <20050411131719.20945.denis.nagorny@intel.com>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From fxcoudert at gcc dot gnu dot org 2005-06-19 07:34 -------
On Pentium III (Coppermine), 864 MHz, 256 KB cache, with linux. Timing in seconds:
g77: 9.52s
gfortran: 9.49s
g77 -O2: 3.11s
gfortran -O2: 3.39s
g77 -O3 -ffast-math: 3.09s
gfortran -O3 -ffast-math: 3.37s
So, I can't confirm your timings. You should perhaps use longer loops (since
your timings are less than a second, you could see the effect of something
external to the floating-point performance itself).
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20945