[turbofan] Make MachineType a pair of enums.

src/compiler/representation-change.h

Index: src/compiler/representation-change.h
diff --git a/src/compiler/representation-change.h b/src/compiler/representation-change.h
index c26fdd3dcd62e3ccc28de6ed3a797664353e306b..b157b0b3feffcffaaf7bf4f70ffb9976801934ed 100644
--- a/src/compiler/representation-change.h
+++ b/src/compiler/representation-change.h
@@ -86,20 +86,22 @@ class RepresentationChanger final {
   // parameter is only used for sanity checking - if the changer cannot figure
   // out signedness for the word32->float64 conversion, then we check that the
   // uses truncate to word32 (so they do not care about signedness).
-  Node* GetRepresentationFor(Node* node, MachineTypeUnion output_type,
-                             MachineTypeUnion use_rep,
+  Node* GetRepresentationFor(Node* node, MachineType output_type,
+                             MachineRepresentation use_rep,
                              Truncation truncation = Truncation::None());
   const Operator* Int32OperatorFor(IrOpcode::Value opcode);
   const Operator* Uint32OperatorFor(IrOpcode::Value opcode);
   const Operator* Float64OperatorFor(IrOpcode::Value opcode);
-  MachineType TypeFromUpperBound(Type* type);
+  MachineSemantic TypeFromUpperBound(Type* type);
 
   MachineType TypeForBasePointer(const FieldAccess& access) {
-    return access.tag() != 0 ? kMachAnyTagged : kMachPtr;
+    return access.tag() != 0 ? MachineType::AnyTagged()
+                             : MachineType::Pointer();
   }
 
   MachineType TypeForBasePointer(const ElementAccess& access) {
-    return access.tag() != 0 ? kMachAnyTagged : kMachPtr;
+    return access.tag() != 0 ? MachineType::AnyTagged()
+                             : MachineType::Pointer();
   }
 
  private:
@@ -111,16 +113,16 @@ class RepresentationChanger final {
   bool testing_type_errors_;  // If {true}, don't abort on a type error.
   bool type_error_;           // Set when a type error is detected.
 
-  Node* GetTaggedRepresentationFor(Node* node, MachineTypeUnion output_type);
-  Node* GetFloat32RepresentationFor(Node* node, MachineTypeUnion output_type,
+  Node* GetTaggedRepresentationFor(Node* node, MachineType output_type);
+  Node* GetFloat32RepresentationFor(Node* node, MachineType output_type,
                                     Truncation truncation);
-  Node* GetFloat64RepresentationFor(Node* node, MachineTypeUnion output_type,
+  Node* GetFloat64RepresentationFor(Node* node, MachineType output_type,
                                     Truncation truncation);
-  Node* GetWord32RepresentationFor(Node* node, MachineTypeUnion output_type);
-  Node* GetBitRepresentationFor(Node* node, MachineTypeUnion output_type);
-  Node* GetWord64RepresentationFor(Node* node, MachineTypeUnion output_type);
-  Node* TypeError(Node* node, MachineTypeUnion output_type,
-                  MachineTypeUnion use);
+  Node* GetWord32RepresentationFor(Node* node, MachineType output_type);
+  Node* GetBitRepresentationFor(Node* node, MachineType output_type);
+  Node* GetWord64RepresentationFor(Node* node, MachineType output_type);
+  Node* TypeError(Node* node, MachineType output_type,
+                  MachineRepresentation use);
   Node* MakeTruncatedInt32Constant(double value);
   Node* InsertChangeFloat32ToFloat64(Node* node);
   Node* InsertChangeTaggedToFloat64(Node* node);