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

[steven at gcc dot gnu.org]

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

Steven Bosscher <steven at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |missed-optimization
          Component|target                      |tree-optimization

--- Comment #13 from Steven Bosscher <steven at gcc dot gnu.org> 2013-02-14 17:26:08 UTC ---
$ g++ --version
g++ (GCC) 4.7.2 ...
$ g++ -O3 -std=c++11 by-val-O3.ii ; ./a.out
Took 14.31 seconds total.
$ g++ -O3 -std=c++11 by-val-O3.ii -fvect-cost-model ; ./a.out
Took 14.31 seconds total.
$ g++ -O3 -std=c++11 by-val-O3.ii -fno-tree-vectorize ; ./a.out
Took 10.25 seconds total.