[Bug tree-optimization/50955] New: IVopts incorrectly rewrite the address of a global memory access into a local form.

[duyuehai at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50955

             Bug #: 50955
           Summary: IVopts incorrectly rewrite the address of a global
                    memory access into a local form.
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: duyue...@gmail.com


Created attachment 25686
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=25686
testcase

IVopts use a weird IV candidate to rewrite a memory address, after this
transform, a non-local memory access have been changed to a local one, and 
lately it was deleted by pass_cd_dce.
see http://gcc.gnu.org/ml/gcc/2011-11/msg00002.html for more details.