[PATCH] Hoist load based on alias analysis

[hfinkel at anl.gov]

> And tried to hoist loading in[i]. isSameOperationAs() filters it out because the types are different.

Understood, thanks for checking. When dealing with C++ classes, etc. there are a lot of bitcasts flying around, and I did not want to change behavior here without knowing what we might regress. We probably should handle the "one side will need a bitcast" case, but that is a separate issue.

LGTM, thanks!

http://reviews.llvm.org/D5991