Clauses in a landingpad are always Constant. Use a stricter type.

llvm-svn: 210203
diff --git a/llvm/lib/IR/Instructions.cpp b/llvm/lib/IR/Instructions.cpp
index 13c51b8..592cdd8 100644
--- a/llvm/lib/IR/Instructions.cpp
+++ b/llvm/lib/IR/Instructions.cpp
@@ -248,7 +248,7 @@
   Use::zap(OldOps, OldOps + e, true);
 }
 
-void LandingPadInst::addClause(Value *Val) {
+void LandingPadInst::addClause(Constant *Val) {
   unsigned OpNo = getNumOperands();
   growOperands(1);
   assert(OpNo < ReservedSpace && "Growing didn't work!");