gcc/testsuite/gcc.dg/pr70747.c

/* { dg-do compile } */
/* { dg-options "-pedantic" } */

int *a, b;

void fn1 ()
{
  a = __builtin_malloc (sizeof(int)*2); 
  b = &a[1] == (0, 0); /* { dg-warning "comparison between pointer and integer" } */
}