[InstCombine] Make foldSelectOpOp able to handle two-operand getelementptr

Three (or more) operand getelementptrs could plausibly also be handled, but
handling only two-operand fits in easily with the existing BinaryOperator
handling.

Differential Revision: https://reviews.llvm.org/D39958


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@322930 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed