Use the struct instead of a std::pair<Value *, Value *>. This makes a
Range an obviously immutable object, and we can now assert that a
range is well-typed (Begin->getType() == End->getType()) on its
construction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226804 91177308-0d34-0410-b5e6-96231b3b80d8