[Bug middle-end/21082] New: &a[b] - &a[c] is not folded to b - c

["pinskia at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

The following C++ code is not fully as optimizated as the C version:
typedef __SIZE_TYPE__ size_t;
size_t a[100];
size_t f(size_t b, size_t c)
{
  return &a[b] - &a[c];
}

Found this while looking into the tree dump for mgrid.

-- 
           Summary: &a[b] - &a[c] is not folded to b - c
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P2
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21082