[PATCH] Properly disregard non-aliased variables in ref_maybe_used_by_call_p_1 and call_may_clobber_ref_p_1

[Paolo Bonzini]

> +   /* If the reference is based on a decl that is not aliased the call
> +      cannot possibly clobber it.  */
> +       /* But local non-readonly statics can be modified through recursion!  */

Isn't there a flag for subroutines in cgraph saying whether they're part
of cycles (for static subroutines whose address is not taken)?  If not,
it would not be hard to implement in the pure-const pass and in any
case, the builtin hack could be included there.

Paolo