[Bug middle-end/40946] New: [4.3/4.4/4.5 Regression] Spurious array subscript is above bounds warning

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

/* { dg-do compile } */
/* { dg-options "-O2 -Wall" } */

struct A
{
  unsigned char a1[8];
  unsigned short a2, a3, a4, a5, a6, a7;
};

int bar (void *, const char *, int);
char *foo (void *, int);

char *
baz (const char *x, const char *y)
{
  int a = sizeof (struct A) + 2 * (__builtin_strlen (y)
   + __builtin_strlen (x) + 24) + 16;
  struct A *b = __builtin_malloc (a);
  char *c;
  int d;

  b->a4 = sizeof (struct A);
  c = ((char *) b) + b->a4;
  d = ((char *) b) + a - c;
  b->a2 = b->a3 = (unsigned short) bar (c, y, d);/* { dg-bogus "array subscript
is above array bounds" } */
  c += b->a2;
  d = ((char *) b) + a - c;
  b->a7 = b->a4 + b->a2;
  b->a5 = b->a6 = (unsigned short) bar (c, x, d);
  c = foo (b, a);
  return c;
}

gives a spurious warning, because the cast of the struct to char pointer is
folded into array ref on the first field.


-- 
           Summary: [4.3/4.4/4.5 Regression] Spurious array subscript is
                    above bounds warning
           Product: gcc
           Version: 4.4.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jakub at gcc dot gnu dot org
GCC target triplet: powerpc-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40946