[Bug tree-optimization/56309] -O3 optimizer generates conditional moves instead of compare and branch resulting in almost 2x slower code

ubizjak at gmail dot com gcc-bugzilla@gcc.gnu.org
Thu Feb 14 17:50:00 GMT 2013


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56309

--- Comment #17 from Uros Bizjak <ubizjak at gmail dot com> 2013-02-14 17:49:46 UTC ---
(In reply to comment #16)

> And it executed fast:
> 
> ./by-val-O3-flags
> Took 6.74 seconds total.

The solution to all these PRs is trivial: kill -ftree-loop-if-convert on x86,
until infrastructure to detect possible stalls is implemented. This decision
needs lots of benchmarking, though.



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