[Bug c/52406] New: likely wrong code bug

[regehr at cs dot utah.edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52406

             Bug #: 52406
           Summary: likely wrong code bug
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: reg...@cs.utah.edu


regehr@john-home:~/z/reduce/1$ current-gcc -O2 small.c ; ./a.out 
1
regehr@john-home:~/z/reduce/1$ current-gcc -O3 small.c ; ./a.out 
0
regehr@john-home:~/z/reduce/1$ current-gcc -v
Using built-in specs.
COLLECT_GCC=current-gcc
COLLECT_LTO_WRAPPER=/home/regehr/z/compiler-install/gcc-r184581-install/libexec/gcc/x86_64-unknown-linux-gnu/4.7.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../configure --enable-lto
--prefix=/home/regehr/z/compiler-install/gcc-r184581-install
--program-prefix=r184581- --enable-languages=c,c++
Thread model: posix
gcc version 4.7.0 20120226 (experimental) (GCC) 
regehr@john-home:~/z/reduce/1$ cat small.c
int printf (const char *, ...);

struct
{
  int f1;
} a[2];

int *b, *const k = &a[1].f1;

static int **c = &b;

int e, f, d;

int main ()
{
  int **l = &b;
  *l = k;
  for ( ; d <= 0; d++ )
    {
      int *j = &e;
      **c = 1;
      *l = k;
      *k ^= 0;
      f = **l;
      *j = f;
    }
  printf ( "%d\n", e );
  return 0;
}