[Bug tree-optimization/47770] New: wrong code -O2 -ftree-loop-if-convert-stores -fno-tree-reassoc

[zsojka at seznam dot cz]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47770

           Summary: wrong code -O2 -ftree-loop-if-convert-stores
                    -fno-tree-reassoc
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: zso...@seznam.cz
                CC: s...@gcc.gnu.org
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu


Created attachment 23365
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23365
reduced testcase

Output:
$ gcc -O2 -ftree-loop-if-convert-stores -fno-tree-reassoc testcase.c
$ ./a.out
Aborted

By looking that the dumps testcase.c.110t.ifcvt is "binary equal" to
testcase.c.109t.ivcanon, but with -ftree-loop-if-convert-stores, 
testcase.c.126t.cddce2 removes most of code of foo(). Dumps with and without
-ftree-loop-if-convert-stores are the same up to that point.