[turbofan] Correctify representation changes to bit.

src/compiler/representation-change.h

 // Copyright 2014 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.
 
 #ifndef V8_COMPILER_REPRESENTATION_CHANGE_H_
 #define V8_COMPILER_REPRESENTATION_CHANGE_H_
 
 #include <sstream>
 
 #include "src/base/bits.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/machine-operator.h"
 #include "src/compiler/node-properties-inl.h"
 #include "src/compiler/simplified-operator.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 // Contains logic related to changing the representation of values for constants
 // and other nodes, as well as lowering Simplified->Machine operators.
 // Eagerly folds any representation changes for constants.
 class RepresentationChanger {
  public:
   RepresentationChanger(JSGraph* jsgraph, SimplifiedOperatorBuilder* simplified,
                         Isolate* isolate)
       : jsgraph_(jsgraph),
         simplified_(simplified),
         isolate_(isolate),
+        bit_range_(Type::Range(isolate->factory()->NewNumber(0),
+                               isolate->factory()->NewNumber(1),
+                               jsgraph->zone())),
         testing_type_errors_(false),
         type_error_(false) {}
 
   // TODO(titzer): should Word64 also be implicitly convertable to others?
-  static const MachineTypeUnion rWord =
-      kRepBit | kRepWord8 | kRepWord16 | kRepWord32;
+  static const MachineTypeUnion rWord = kRepWord8 | kRepWord16 | kRepWord32;
 
   Node* GetRepresentationFor(Node* node, MachineTypeUnion output_type,
                              MachineTypeUnion use_type) {
     if (!base::bits::IsPowerOfTwo32(output_type & kRepMask)) {
       // There should be only one output representation.
       return TypeError(node, output_type, use_type);
     }
     if ((use_type & kRepMask) == (output_type & kRepMask)) {
       // Representations are the same. That's a no-op.
       return node;
@@ skipping 209 matching lines @@
         return node;  // No change necessary.
       case IrOpcode::kFloat32Constant:
         return MakeInt32Constant(OpParameter<float>(node));
       case IrOpcode::kNumberConstant:
       case IrOpcode::kFloat64Constant:
         return MakeInt32Constant(OpParameter<double>(node));
       default:
         break;
     }
     // Select the correct X -> Word32 operator.
-    const Operator* op = NULL;
-    if (output_type & kRepFloat64) {
+    const Operator* op;
+    if (output_type & kRepBit) {
+      return node;  // No change necessary.
+    } else if (output_type & kRepFloat64) {
       if (output_type & kTypeUint32 || use_unsigned) {
         op = machine()->ChangeFloat64ToUint32();
       } else {
         op = machine()->ChangeFloat64ToInt32();
       }
     } else if (output_type & kRepFloat32) {
       node = InsertChangeFloat32ToFloat64(node);  // float32 -> float64 -> int32
       if (output_type & kTypeUint32 || use_unsigned) {
         op = machine()->ChangeFloat64ToUint32();
       } else {
@@ skipping 14 matching lines @@
   Node* GetBitRepresentationFor(Node* node, MachineTypeUnion output_type) {
     // Eagerly fold representation changes for constants.
     switch (node->opcode()) {
       case IrOpcode::kInt32Constant: {
         int32_t value = OpParameter<int32_t>(node);
         if (value == 0 || value == 1) return node;
         return jsgraph()->Int32Constant(1);  // value != 0
       }
       case IrOpcode::kNumberConstant: {
         double value = OpParameter<double>(node);
-        if (std::isnan(value) || value == 0.0) {
-          return jsgraph()->Int32Constant(0);
-        }
-        return jsgraph()->Int32Constant(1);
+        if (value == 0.0 || value != value) return jsgraph()->Int32Constant(0);

[Jarin, 2015/01/08 09:18:13]

Just for my education: why is value != value better than std::isnan?

[Benedikt Meurer, 2015/01/08 09:20:01]

It's not...

+        return jsgraph()->Int32Constant(1);  // value != +0.0, -0.0, NaN
       }
       case IrOpcode::kHeapConstant: {
-        Handle<Object> handle = OpParameter<Unique<Object> >(node).handle();
-        DCHECK(*handle == isolate()->heap()->true_value() ||
-               *handle == isolate()->heap()->false_value());
-        return jsgraph()->Int32Constant(
-            *handle == isolate()->heap()->true_value() ? 1 : 0);
+        Handle<Object> object = OpParameter<Unique<Object>>(node).handle();
+        return jsgraph()->Int32Constant(object->BooleanValue() ? 1 : 0);
       }
       default:
         break;
     }
     // Select the correct X -> Bit operator.
     const Operator* op;
     if (output_type & rWord) {
-      return node;  // No change necessary.
+      op = simplified()->ChangeWord32ToBit();
     } else if (output_type & kRepWord64) {
-      return node;  // TODO(titzer): No change necessary, on 64-bit.
+      op = simplified()->ChangeWord64ToBit();
     } else if (output_type & kRepTagged) {
-      op = simplified()->ChangeBoolToBit();
+      Type* upper = NodeProperties::GetBounds(node).upper;
+      if (upper->Is(Type::Boolean())) {
+        op = simplified()->ChangeBoolToBit();
+      } else if (upper->Is(Type::Signed32())) {
+        // Tagged -> Int32 -> Bit
+        node = InsertChangeTaggedToInt32(node);
+        op = simplified()->ChangeWord32ToBit();
+      } else if (upper->Is(Type::Unsigned32())) {
+        // Tagged -> Uint32 -> Bit
+        node = InsertChangeTaggedToUint32(node);
+        op = simplified()->ChangeWord32ToBit();
+      } else {
+        return TypeError(node, output_type, kRepBit);
+      }
     } else {
       return TypeError(node, output_type, kRepBit);
     }
-    return jsgraph()->graph()->NewNode(op, node);
+    return graph()->NewNode(op, node);
   }
 
   Node* GetWord64RepresentationFor(Node* node, MachineTypeUnion output_type) {
     if (output_type & kRepBit) {
       return node;  // Sloppy comparison -> word64
     }
     // Can't really convert Word64 to anything else. Purported to be internal.
     return TypeError(node, output_type, kRepWord64);
   }
 
@@ skipping 84 matching lines @@
     if (type->Is(Type::Unsigned32())) return kTypeUint32;
     if (type->Is(Type::Number())) return kTypeNumber;
     if (type->Is(Type::Boolean())) return kTypeBool;
     return kTypeAny;
   }
 
  private:
   JSGraph* jsgraph_;
   SimplifiedOperatorBuilder* simplified_;
   Isolate* isolate_;
+  Type* bit_range_;
 
   friend class RepresentationChangerTester;  // accesses the below fields.
 
   bool testing_type_errors_;  // If {true}, don't abort on a type error.
   bool type_error_;           // Set when a type error is detected.
 
   Node* TypeError(Node* node, MachineTypeUnion output_type,
                   MachineTypeUnion use) {
     type_error_ = true;
     if (!testing_type_errors_) {
       std::ostringstream out_str;
       out_str << static_cast<MachineType>(output_type);
 
       std::ostringstream use_str;
       use_str << static_cast<MachineType>(use);
 
       V8_Fatal(__FILE__, __LINE__,
                "RepresentationChangerError: node #%d:%s of "
                "%s cannot be changed to %s",
                node->id(), node->op()->mnemonic(), out_str.str().c_str(),
                use_str.str().c_str());
     }
     return node;
   }
 
   Node* InsertChangeFloat32ToFloat64(Node* node) {
-    return jsgraph()->graph()->NewNode(machine()->ChangeFloat32ToFloat64(),
-                                       node);
+    return graph()->NewNode(machine()->ChangeFloat32ToFloat64(), node);
   }
 
   Node* InsertChangeTaggedToFloat64(Node* node) {
-    return jsgraph()->graph()->NewNode(simplified()->ChangeTaggedToFloat64(),
-                                       node);
+    return graph()->NewNode(simplified()->ChangeTaggedToFloat64(), node);
   }
 
-  JSGraph* jsgraph() { return jsgraph_; }
-  Isolate* isolate() { return isolate_; }
-  SimplifiedOperatorBuilder* simplified() { return simplified_; }
-  MachineOperatorBuilder* machine() { return jsgraph()->machine(); }
+  Node* InsertChangeTaggedToInt32(Node* node) {
+    return graph()->NewNode(simplified()->ChangeTaggedToInt32(), node);
+  }
+
+  Node* InsertChangeTaggedToUint32(Node* node) {
+    return graph()->NewNode(simplified()->ChangeTaggedToUint32(), node);
+  }
+
+  Graph* graph() const { return jsgraph()->graph(); }
+  JSGraph* jsgraph() const { return jsgraph_; }
+  Isolate* isolate() const { return isolate_; }
+  SimplifiedOperatorBuilder* simplified() const { return simplified_; }
+  MachineOperatorBuilder* machine() const { return jsgraph()->machine(); }
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_REPRESENTATION_CHANGE_H_