[Bug tree-optimization/54073] [4.7/4.8 Regression] SciMark Monte Carlo test performance has seriously decreased in recent GCC releases

[ubizjak at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54073

--- Comment #10 from Uros Bizjak <ubizjak at gmail dot com> 2012-11-13 15:13:56 UTC ---
(In reply to comment #8)

> The attached proof of concept patch attempts to just restore the 4.6 and
> earlier behavior by allowing in all comparisons.  Of course perhaps it might be
> possible it needs better tuning than that, I meant it just as a start for
> discussions.

Please see PR53346, from comment 14 onwards, especially H.J.'s comment:

-quote-
I was told that cmov wins if branch is mispredicted, otherwise
cmov loses.  We will investigate if we can improve cmov in GCC.
-/quote-