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[Bug optimization/13712] Executable runs 25% slower than when compiled with INTEL compiler
- From: "uros at kss-loka dot si" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 16 Feb 2004 14:55:11 -0000
- Subject: [Bug optimization/13712] Executable runs 25% slower than when compiled with INTEL compiler
- References: <20040116211131.13712.william.crocker@analog.com>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From uros at kss-loka dot si 2004-02-16 14:55 -------
I have done some experiments with CVS gcc-3.5 [3.5.0 20040216 (experimental)]
and gcc-3.2 [3.2 20020903 (Red Hat Linux 8.0 3.2-7)] on P4 3.2GHz, using various
options.
gcc-3.2: g++ -O3
X422 = 469.196
real 0m35.219s
user 0m35.143s
sys 0m0.061s
gcc-3.2: g++ -march=i686 -O3 -ffast-math
X422 = 469.196
real 0m29.439s
user 0m29.410s
sys 0m0.021s
gcc-3.5: g++ -march=i686 -O3 -ffast-math
X422 = 469.196
real 0m26.380s
user 0m26.287s
sys 0m0.004s
gcc-3.5: g++ -march=i686 -msse2 -mfpmath=sse -O3 -ffast-math
X422 = 469.196
real 0m26.591s
user 0m26.359s
sys 0m0.059s
gcc-3.5: g++ -march=i686 -O3 -ffast-math,
with all functions in source changed to __builtin_<function>:
HUGE_VAL => __builtin_huge_val()
sqrt() => __builtin_sqrt()
log() => __builtin_log()
exp() => __built_in_exp()
X422 = 469.196
real 0m23.145s
user 0m23.115s
sys 0m0.018s
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13712