by checking that the top-level type of a gep is sized. This
causes us to reject the example with:
llvm-as: t2.ll:2:16: invalid getelementptr indices
getelementptr i32()* null, i32 1
^
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66393 91177308-0d34-0410-b5e6-96231b3b80d8