/* { dg-do compile } */ /* { dg-options "-O2 -Wall" } */ struct g { long a; }; unsigned long f(struct g *a) { return *(unsigned long *)&a->a; } struct A { void *a; }; int g(const struct A *x, long *y) { typedef long __attribute__ ((may_alias)) long_a; *y = *(const long_a *) (&x->a); return 1; } void *a; int f0 (long *y) { *y = *(const long *) &a; /* { dg-warning "will break" } */ return 1; } int f1 (long *y) { typedef long __attribute__ ((may_alias)) long_a; *y = *(const long_a *) &a; return 1; } int f2 (long *y) { *y = *(const long *) &a; /* { dg-warning "will break" } */ return 1; }