[Bug tree-optimization/29751] New: Missed optimization of restrict pointer assigned value

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

In the following program, the if() is only removed if one removes the line
"r[1]=0;". (4.3.0 20061107; x86_64-unknown-linux-gnu-gcc)

#include <stdlib.h>
void foo (void);
int main() {
  int *restrict r;
  r = malloc(2*sizeof(int));
  r[0] = 0;
  r[1] = 0;
  if(r[0]) foo();
  return 0;
}


main ()
{
  int * restrict r;
  void * D.1998;
<bb 2>:
  D.1998 = malloc (8);
  r = (int * restrict) D.1998;
  *r = 0;
  *(r + 4B) = 0;
  if (*r != 0) goto <L0>; else goto <L1>;
<L0>:;
  foo ();
<L1>:;
  return 0;
}


-- 
           Summary: Missed optimization of restrict pointer assigned value
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: burnus at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29751