Prompted by the optimizer bug submitted by Geoffrey Broadwell (see https://rt.perl.org/rt3/Ticket/Display.html?id=49968), I decided to revisit this one. After updating, I got the code to compile under Parrot r24875. So either the original problem was somehow fixed, or it shifted in such a way that the test case no longer triggers it. Either way, this ticket should probably be closed. (But I don't seem to be able to do this.)
-- Bob Rogers http://rgrjr.dyndns.org/ P.S. All of the updates were obvious (change "PerlInt" to "Integer", etc.), so I see no point in attaching the updated PIR code.