PrelRules: Handle Int left shifts of more than word-size bits
authorBen Gamari <bgamari.foss@gmail.com>
Tue, 26 Sep 2017 12:01:44 +0000 (08:01 -0400)
committerBen Gamari <ben@smart-cactus.org>
Tue, 26 Sep 2017 15:59:53 +0000 (11:59 -0400)
commit57372a7cc958ebfa4ac64fc800e00baacfc3cf5c
tree55a199e3d994dc38f959ca98ac881e3a4ed6a74d
parent1d1b991ee15e0428be16d1bfad7087051e000bdc
PrelRules: Handle Int left shifts of more than word-size bits

This should result in zero. Failing to realize this caused us to try
to constant-fold via the normal path, resulting in #14272.

Test Plan: Validate with coming tests

Reviewers: austin, simonpj

Subscribers: simonpj, rwbarton, thomie, hvr

GHC Trac Issues: #14272

Differential Revision: https://phabricator.haskell.org/D4025
compiler/prelude/PrelRules.hs