comparing pointers inside builtins.c

[Richard Kenner]

    A number of the builtins - e.g. memcpy, strcmp - could benefit from
    knowing whether their pointer arguments are equal: the same constant
    or the same variable.  Inside builtins.c, we're looking at trees.
    What is the appropriate way, given two pointers as trees, to decide
    whether we know they point to the same address?

How about operand_equal_p?