Two changes:

Two changes:
1. Fix logic for executeGEP. Only 32-bit and 64-bit integer types are
   acceptable as indices.
2. Ensure that all integer cast operations truncate their result to the
   integer size of the operand.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33318 91177308-0d34-0410-b5e6-96231b3b80d8