[turbofan] Fold word32 representation changes for checked constants.

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 350 matching lines @@
 }
 
 Node* RepresentationChanger::MakeTruncatedInt32Constant(double value) {
   return jsgraph()->Int32Constant(DoubleToInt32(value));
 }
 
 Node* RepresentationChanger::GetWord32RepresentationFor(
     Node* node, MachineRepresentation output_rep, Type* output_type,
     Node* use_node, UseInfo use_info) {
   // Eagerly fold representation changes for constants.
-  // TODO(jarin) Properly fold constants in presence of type check.
-  if (use_info.type_check() == TypeCheckKind::kNone) {
-    switch (node->opcode()) {
-      case IrOpcode::kInt32Constant:
-        return node;  // No change necessary.
-      case IrOpcode::kFloat32Constant:
-        return MakeTruncatedInt32Constant(OpParameter<float>(node));
-      case IrOpcode::kNumberConstant:
-      case IrOpcode::kFloat64Constant:
-        return MakeTruncatedInt32Constant(OpParameter<double>(node));
-      default:
-        break;
+  switch (node->opcode()) {
+    case IrOpcode::kInt32Constant:
+      return node;  // No change necessary.
+    case IrOpcode::kFloat32Constant: {
+      float const fv = OpParameter<float>(node);
+      if (use_info.type_check() == TypeCheckKind::kNone ||
+          (use_info.type_check() == TypeCheckKind::kSigned32 &&
+           IsInt32Double(fv))) {
+        return MakeTruncatedInt32Constant(fv);
+      }
+      break;
     }
+    case IrOpcode::kNumberConstant:
+    case IrOpcode::kFloat64Constant: {
+      double const fv = OpParameter<double>(node);
+      if (use_info.type_check() == TypeCheckKind::kNone ||
+          (use_info.type_check() == TypeCheckKind::kSigned32 &&
+           IsInt32Double(fv))) {
+        return MakeTruncatedInt32Constant(fv);
+      }
+      break;
+    }
+    default:
+      break;
   }
 
   // Select the correct X -> Word32 operator.
   const Operator* op = nullptr;
   if (output_rep == MachineRepresentation::kBit) {
     return node;  // Sloppy comparison -> word32
   } else if (output_rep == MachineRepresentation::kFloat64) {
     if (output_type->Is(Type::Unsigned32())) {
       op = machine()->ChangeFloat64ToUint32();
     } else if (output_type->Is(Type::Signed32())) {
@@ skipping 363 matching lines @@
 }
 
 Node* RepresentationChanger::InsertChangeTaggedToFloat64(Node* node) {
   return jsgraph()->graph()->NewNode(simplified()->ChangeTaggedToFloat64(),
                                      node);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8