[Bug tree-optimization/52868] New: [4.6/4.7/4.8 Regression] 4.6 is faster on Atom

[izamyatin at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52868

             Bug #: 52868
           Summary: [4.6/4.7/4.8 Regression] 4.6 is faster on Atom
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: izamyatin@gmail.com
            Target: i386


Created attachment 27090
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27090
Testcase

For attached case 4.6 is ~10% faster than 4.7 and trunk.

IVopts works differently and it leads to performance degradation

THis is possibly related to http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52272

Command line to reproduce:
-O2 -march=atom -m32 -mtune=atom -msse2 -static