[Bug target/27855] [4.5/4.7/4.8 regression] reassociation causes the RA to be confused

[ubizjak at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27855

Uros Bizjak <ubizjak at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|i686-pc-linux-gnu           |i686-pc-linux-gnu,
                   |                            |x86_64-pc-linux-gnu
             Status|WAITING                     |NEW

--- Comment #44 from Uros Bizjak <ubizjak at gmail dot com> 2013-01-16 16:40:36 UTC ---
Still the same old story...

Target: x86_64-unknown-linux-gnu
gcc version 4.8.0 20130116 (experimental) [trunk revision 195240] (GCC) 

corei7 SNB:

-DREPS=10000 -msse3 -O2 -ffast-math

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

atlasmm       60  10000       1.636     2640.99

-DREPS=10000 -msse3 -O2 -ffast-math -fno-tree-reassoc

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

atlasmm       60  10000       1.218     3547.34

-DREPS=10000 -msse3 -O2 -ffast-math -ftree-vectorize

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

atlasmm       60  10000       1.654     2612.25

-DREPS=10000 -msse3 -O2 -ffast-math -ftree-vectorize -fno-tree-reassoc

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

atlasmm       60  10000       1.555     2778.56

The testcase is at http://www.cs.utsa.edu/~whaley/mmbench4.tar.gz

Reconfirmed with 4.8.0.