Patch by Andrew Wilkins!
canAvoidElementLoad and canAvoidLoad were incorrectly
eliding loads when an index expression is used as an
another array index expression. This led to a panic.
See comments on https://github.com/go-llvm/llgo/issues/175
Test Plan: lit test added
Differential Revision: http://reviews.llvm.org/D6676
llvm-svn: 224420
Peter Collingbourne