[turbofan] Optimize tagged conversion based on type.

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 172 matching lines @@
     case IrOpcode::kFloat32Constant:
       return jsgraph()->Constant(OpParameter<float>(node));
     default:
       break;
   }
   // Select the correct X -> Tagged operator.
   const Operator* op;
   if (output_rep == MachineRepresentation::kBit) {
     op = simplified()->ChangeBitToBool();
   } else if (IsWord(output_rep)) {
-    if (output_type->Is(Type::Unsigned32())) {
-      op = simplified()->ChangeUint32ToTagged();
+    if (output_type->Is(Type::Signed31())) {
+      op = simplified()->ChangeInt31ToTagged();
     } else if (output_type->Is(Type::Signed32())) {
       op = simplified()->ChangeInt32ToTagged();
+    } else if (output_type->Is(Type::Unsigned32())) {
+      op = simplified()->ChangeUint32ToTagged();
     } else {
       return TypeError(node, output_rep, output_type,
                        MachineRepresentation::kTagged);
     }
   } else if (output_rep ==
              MachineRepresentation::kFloat32) {  // float32 -> float64 -> tagged
     node = InsertChangeFloat32ToFloat64(node);
+    // TODO(bmeurer): Pass -0 hint to ChangeFloat64ToTagged.
     op = simplified()->ChangeFloat64ToTagged();
   } else if (output_rep == MachineRepresentation::kFloat64) {
-    op = simplified()->ChangeFloat64ToTagged();
+    if (output_type->Is(Type::Signed31())) {  // float64 -> int32 -> tagged
+      node = InsertChangeFloat64ToInt32(node);
+      op = simplified()->ChangeInt31ToTagged();
+    } else if (output_type->Is(
+                   Type::Signed32())) {  // float64 -> int32 -> tagged
+      node = InsertChangeFloat64ToInt32(node);
+      op = simplified()->ChangeInt32ToTagged();
+    } else if (output_type->Is(
+                   Type::Unsigned32())) {  // float64 -> uint32 -> tagged
+      node = InsertChangeFloat64ToUint32(node);
+      op = simplified()->ChangeUint32ToTagged();
+    } else {
+      // TODO(bmeurer): Pass -0 hint to ChangeFloat64ToTagged.
+      op = simplified()->ChangeFloat64ToTagged();
+    }
   } else {
     return TypeError(node, output_rep, output_type,
                      MachineRepresentation::kTagged);
   }
   return jsgraph()->graph()->NewNode(op, node);
 }
 
 
 Node* RepresentationChanger::GetFloat32RepresentationFor(
     Node* node, MachineRepresentation output_rep, Type* output_type,
@@ skipping 304 matching lines @@
              use_str.str().c_str());
   }
   return node;
 }
 
 
 Node* RepresentationChanger::InsertChangeFloat32ToFloat64(Node* node) {
   return jsgraph()->graph()->NewNode(machine()->ChangeFloat32ToFloat64(), node);
 }
 
+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::InsertChangeTaggedToFloat64(Node* node) {
   return jsgraph()->graph()->NewNode(simplified()->ChangeTaggedToFloat64(),
                                      node);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8