[Bug regression/52272] New: [4.7 regression] Performance regresswion of 410.bwaves on x86.

[vbyakovl23 at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52272

             Bug #: 52272
           Summary: [4.7 regression] Performance regresswion of 410.bwaves
                    on x86.
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: regression
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: vbyakov...@gmail.com


Created attachment 26671
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=26671
Reduced testcase

Commit 
2012-02-06  Richard Guenther  <rguent...@suse.de>

        PR tree-optimization/50955
        * tree-ssa-loop-ivopts.c (get_computation_cost_at): Artificially
        raise cost of expressions that replace an address with an
        expression based on a different pointer.

causes performance regression on 410.bwaves
    base: -2.33%
    peak: -3.82%
I attached a reduced testcase and dumps of compilers before and after commit.
Command line to reproduce

gfortran -w -g -m32  -static -S t.s -O3 -funroll-loops -msse2 -mfpmath=sse
-ffast-math -march=corei7 t.f