[Bug target/27827] [4.0/4.1 Regression] gcc 4 produces worse x87 code on all platforms than gcc 3

[uros at kss-loka dot si]

------- Comment #64 from uros at kss-loka dot si  2006-08-11 09:18 -------
Slightly offtopic, but to put some numbers to comment #8 and comment #11,
equivalent SSE code now reaches only 50% of x87 single performance and 60% of
x87 double performance on AMD x86_64:


ALGORITHM     NB   REPS        TIME      MFLOPS
=========  =====  =====  ==========  ==========

[float] -O2 -mfpmath=sse -march=k8:
atlasmm       60   1000       0.273     1582.66
[float] -O2 -mfpmath=387 -march=k8:
atlasmm       60   1000       0.138     3130.91

[double] -O2 -mfpmath=sse -march=k8:
atlasmm       60   1000       0.252     1714.54
[double] -O2 -mfpmath=387 -march=k8:
atlasmm       60   1000       0.152     2842.55

This effect was first observed in PR19780.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27827