InferAddressSpaces: Infer for just GEPs

Fixes leaving intermediate flat addressing computations
where a GEP instruction's source is a constant expression.

Still leaves behind a trivial addrspacecast + gep pair that
instcombine is able to handle, which ideally could be folded
here directly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301044 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed