[Bug c/21015] New: Bad loop optimization with -O2

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

The enclosed program prints only "0" when compiled with -O2.  It should print
"0" and "1".  I've also tried 3.2.2 and the error is present.

Phil.

#include <stdio.h>

void
f(int start)
{
  int i, end;

  for (i = end = start; i <= end; ++i)
    {
      printf("%d\n", i);
      if (i == start)
	end = 1;
    }
}

int
main()
{
  f(0);
  return 0;
}

-- 
           Summary: Bad loop optimization with -O2
           Product: gcc
           Version: 3.4.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: phil at fifi dot org
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-redhat-linux-gnu
  GCC host triplet: i686-redhat-linux-gnu
GCC target triplet: i686-redhat-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21015