[turbofan] Move more type checks to the representation selector.

src/compiler/representation-change.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/representation-change.h"
 
 #include <sstream>
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 304 matching lines @@
   if (IsWord(output_rep)) {
     if (output_type->Is(Type::Signed32())) {
       op = machine()->ChangeInt32ToFloat64();
     } else if (output_type->Is(Type::Unsigned32()) ||
                truncation.TruncatesToWord32()) {
       // Either the output is uint32 or the uses only care about the
       // low 32 bits (so we can pick uint32 safely).
       op = machine()->ChangeUint32ToFloat64();
     }
   } else if (output_rep == MachineRepresentation::kTagged) {
-    if (output_type->Is(Type::NumberOrUndefined())) {
+    if (output_type->Is(Type::Undefined())) {
+      return jsgraph()->Float64Constant(
+          std::numeric_limits<double>::quiet_NaN());

[Jarin, 2016/04/22 10:35:30]

Nice! Thanks.

+    } else if (output_type->Is(Type::TaggedSigned())) {
+      node = InsertChangeTaggedSignedToInt32(node);
+      op = machine()->ChangeInt32ToFloat64();
+    } else if (output_type->Is(Type::NumberOrUndefined())) {
       op = simplified()->ChangeTaggedToFloat64();
     }
   } else if (output_rep == MachineRepresentation::kFloat32) {
     op = machine()->ChangeFloat32ToFloat64();
   }
   if (op == nullptr) {
     return TypeError(node, output_rep, output_type,
                      MachineRepresentation::kFloat64);
   }
   return jsgraph()->graph()->NewNode(op, node);
@@ skipping 34 matching lines @@
   } else if (output_rep == MachineRepresentation::kFloat32) {
     node = InsertChangeFloat32ToFloat64(node);  // float32 -> float64 -> int32
     if (output_type->Is(Type::Unsigned32())) {
       op = machine()->ChangeFloat64ToUint32();
     } else if (output_type->Is(Type::Signed32())) {
       op = machine()->ChangeFloat64ToInt32();
     } else if (truncation.TruncatesToWord32()) {
       op = machine()->TruncateFloat64ToInt32(TruncationMode::kJavaScript);
     }
   } else if (output_rep == MachineRepresentation::kTagged) {
-    if (output_type->Is(Type::Unsigned32())) {
+    if (output_type->Is(Type::TaggedSigned())) {
+      op = simplified()->ChangeTaggedSignedToInt32();
+    } else if (output_type->Is(Type::Unsigned32())) {
       op = simplified()->ChangeTaggedToUint32();
     } else if (output_type->Is(Type::Signed32())) {
       op = simplified()->ChangeTaggedToInt32();
     } else if (truncation.TruncatesToWord32()) {
       node = InsertChangeTaggedToFloat64(node);
       op = machine()->TruncateFloat64ToInt32(TruncationMode::kJavaScript);
     }
   }
   if (op == nullptr) {
     return TypeError(node, output_rep, output_type,
@@ skipping 155 matching lines @@
 }
 
 Node* RepresentationChanger::InsertChangeFloat64ToUint32(Node* node) {
   return jsgraph()->graph()->NewNode(machine()->ChangeFloat64ToUint32(), node);
 }
 
 Node* RepresentationChanger::InsertChangeFloat64ToInt32(Node* node) {
   return jsgraph()->graph()->NewNode(machine()->ChangeFloat64ToInt32(), node);
 }
 
+Node* RepresentationChanger::InsertChangeTaggedSignedToInt32(Node* node) {
+  return jsgraph()->graph()->NewNode(simplified()->ChangeTaggedSignedToInt32(),
+                                     node);
+}
+
 Node* RepresentationChanger::InsertChangeTaggedToFloat64(Node* node) {
   return jsgraph()->graph()->NewNode(simplified()->ChangeTaggedToFloat64(),
                                      node);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8