Compiling GCC with g++: a report

[Richard Kenner]

    And YES I have a port with multiple pointer sizes, and YES the
    customer wanted both sizes supported in a single compilation unit 

This is actually not that uncommon.

    Oh, and sometimes gcc randomly uses pointer_mode instead of Pmode.  I
    haven't a clue why there's a difference, or how badly gcc would break
    if pointer_mode and Pmode were different.  Ok, I lied, I *do* know how
    badly it breaks if they differ; I did try that at one point.

There have been a number of ports where these differ.  Though undoubtably
there are bugs in this support, it does basically work.