Merge the contents from exception-handling-rewrite to the mainline.

This adds the new instructions 'landingpad' and 'resume'.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136253 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/IPO/GlobalOpt.cpp

@@ -2506,7 +2506,7 @@ static bool EvaluateFunction(Function *F, Constant *&RetVal,
         CallStack.pop_back();  // return from fn.
         return true;  // We succeeded at evaluating this ctor!
       } else {
-        // invoke, unwind, unreachable.
+        // invoke, unwind, resume, unreachable.
         return false;  // Cannot handle this terminator.
       }