500c500
< unsigned Field = cast<ConstantInt>(Idx)->getZExtValue();
---
> uint64_t Field = cast<ConstantInt>(Idx)->getZExtValue();
521,522c521,522
< TotalOffs +=
< DL.getTypeAllocSize(Ty) * cast<ConstantInt>(CI)->getSExtValue();
---
> uint64_t IdxN = CI->getValue().sextOrTrunc(64).getSExtValue();
> TotalOffs += DL.getTypeAllocSize(Ty) * IdxN;