Jonas Scholl authored Jan 22, 2016 and Ben Gamari committed Jan 22, 2016

This fixes #11372 by omitting arguments with a void-type when checking
whether a self-recursive tail call can be optimized to a local jump.
Previously, a function taking a real argument and a State# token
would report an arity of 1 in the SelfLoopInfo in getCallMethod,
but a self-recursive call would apply it to 2 arguments, one of them
being the State# token, thus no local jump would be generated.
As the State# token is not represented by anything at runtime, we can
ignore it and thus trigger the loopification optimization.

Test Plan: ./validate

Reviewers: austin, bgamari, simonmar

Reviewed By: bgamari

Subscribers: simonmar, thomie

Differential Revision: https://phabricator.haskell.org/D1767

GHC Trac Issues: #11372