[Bug target/14478] New: rs6000 geu patterns generate incorrect code

["amodra at bigpond dot net dot au" <gcc-bugzilla at gcc dot gnu dot org>]

Compiling the following with -O results in a function that always returns zero,
instead of one that always returns 1.

int foo (int a, unsigned int x)
{
  unsigned int n = 0;

  while (a)
    x = x + 1, a = a << 1;

  return x >= n;
}

-- 
           Summary: rs6000 geu patterns generate incorrect code
           Product: gcc
           Version: 3.4.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P2
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: amodra at bigpond dot net dot au
                CC: gcc-bugs at gcc dot gnu dot org
GCC target triplet: powerpc-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14478