Make sure value is initialized when built w/o asserts.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@68615 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CGExprScalar.cpp

@@ -854,6 +854,7 @@ Value *ScalarExprEmitter::EmitOverflowCheckedBinOp(const BinOpInfo &Ops) {
     break;
   default:
     assert(false && "Unsupported operation for overflow detection");
+    IID = 0;
   }
   OpID <<= 1;
   OpID |= 1;