[Bug tree-optimization/53342] [4.8 Regression] rnflow.f90 is ~5% slower after revision 187340

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53342

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-12-10 12:10:41 UTC ---
Is this slower compared to pre-r186530 gfortran, or just from the r186530
through 187339?  I think before that change on this testcase we've vectorized
just 25 loops, not 28 loops as now, and supposedly the loops for which the
r187340 change is a problem are only those that weren't vectorized before at
all.  If the latter, then this wouldn't be a regression.

Is there an easy way to detect if peeling could turn a simple_iv vectorized
load into non-!simple_iv?

Michael, do you plan to work on this?