InstSimplify: stripAndComputeConstantOffsets can be called with vectors of pointers too.

Prepare it for vectors of pointers and handle simple cases. We don't handle
complicated cases because accumulateConstantOffset bails on pointer vectors.
Fixes selfhost on i386.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174179 91177308-0d34-0410-b5e6-96231b3b80d8
Add appropriate TSFlags to the instructions that must be always extended.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174186 91177308-0d34-0410-b5e6-96231b3b80d8