CodeGen incorrectly ignores (assert from APInt) constant index bigger
than 2^64 in getelementptr instruction. This is a test and fix for that.
Patch by Paweł Bylica!
Reviewed By: rnk
Subscribers: majnemer, rnk, mcrosier, resistor, llvm-commits
Differential Revision: http://reviews.llvm.org/D8219
llvm-svn: 231984