How to supress a specific kind of ansi-aliasing rules?

[Bokhanko, Andrey S]

Hi,

As I learned from experience, gcc always assume independence between memory 
references in the following program:

typedef struct {
    int m1;
    int m2;
} S1;

void foo(S1 *p1, S1 *p2) {
    ... = p1->m1;
    ... = p2->m2;
}

...even if -fno-strict-aliasing (an option disabling ansi-aliasing rules) 
supplied.

I wonder, is there a way to force gcc not to assume independence in the example 
shown above?

Yours,
Andrey