[turbofan] Support for %_DoubleHi, %_DoubleLo and %_ConstructDouble.

src/compiler/machine-operator-reducer.h

Index: src/compiler/machine-operator-reducer.h
diff --git a/src/compiler/machine-operator-reducer.h b/src/compiler/machine-operator-reducer.h
index f7c3bd7cfde5b04f0eb81e8e80511f84ca101992..7c41f143e20a9709761e1c783c88c06bd862e131 100644
--- a/src/compiler/machine-operator-reducer.h
+++ b/src/compiler/machine-operator-reducer.h
@@ -78,6 +78,8 @@ class MachineOperatorReducer FINAL : public Reducer {
   Reduction ReduceWord32Sar(Node* node);
   Reduction ReduceWord32And(Node* node);
   Reduction ReduceWord32Or(Node* node);
+  Reduction ReduceFloat64InsertLowWord32(Node* node);
+  Reduction ReduceFloat64InsertHighWord32(Node* node);
 
   Graph* graph() const;
   JSGraph* jsgraph() const { return jsgraph_; }