[turbofan] Introduce dedicated ObjectIsNaN operator.

We can compile a !== a and Number.isNaN(a) to ObjectIsNaN. The former is
commonly used to check for NaN, i.e. in case of equals in AngularJS.

R=jarin@chromium.org
BUG=v8:5267

Review-Url: https://codereview.chromium.org/2722483003
Cr-Commit-Position: refs/heads/master@{#43572}

src/compiler/effect-control-linearizer.cc

@@ -720,6 +720,9 @@ bool EffectControlLinearizer::TryWireInStateEffect(Node* node,
     case IrOpcode::kObjectIsDetectableCallable:
       result = LowerObjectIsDetectableCallable(node);
       break;
+    case IrOpcode::kObjectIsNaN:
+      result = LowerObjectIsNaN(node);
+      break;
     case IrOpcode::kObjectIsNonCallable:
       result = LowerObjectIsNonCallable(node);
       break;
@@ -1717,6 +1720,29 @@ Node* EffectControlLinearizer::LowerObjectIsDetectableCallable(Node* node) {
   return done.PhiAt(0);
 }
 
+Node* EffectControlLinearizer::LowerObjectIsNaN(Node* node) {
+  Node* value = node->InputAt(0);
+  Node* zero = __ Int32Constant(0);
+
+  auto done = __ MakeLabel<3>(MachineRepresentation::kBit);
+
+  // Check if {value} is a Smi.
+  __ GotoIf(ObjectIsSmi(value), &done, zero);
+
+  // Check if {value} is a HeapNumber.
+  Node* value_map = __ LoadField(AccessBuilder::ForMap(), value);
+  __ GotoUnless(__ WordEqual(value_map, __ HeapNumberMapConstant()), &done,
+                zero);
+
+  // Check if {value} contains a NaN.
+  Node* value_value = __ LoadField(AccessBuilder::ForHeapNumberValue(), value);
+  __ Goto(&done,
+          __ Word32Equal(__ Float64Equal(value_value, value_value), zero));
+
+  __ Bind(&done);
+  return done.PhiAt(0);
+}
+
 Node* EffectControlLinearizer::LowerObjectIsNonCallable(Node* node) {
   Node* value = node->InputAt(0);
 

src/compiler/effect-control-linearizer.h

@@ -81,6 +81,7 @@ class V8_EXPORT_PRIVATE EffectControlLinearizer {
   Node* LowerTruncateTaggedToWord32(Node* node);
   Node* LowerCheckedTruncateTaggedToWord32(Node* node, Node* frame_state);
   Node* LowerObjectIsDetectableCallable(Node* node);
+  Node* LowerObjectIsNaN(Node* node);
   Node* LowerObjectIsNonCallable(Node* node);
   Node* LowerObjectIsNumber(Node* node);
   Node* LowerObjectIsReceiver(Node* node);

src/compiler/js-builtin-reducer.cc

@@ -1513,14 +1513,10 @@ Reduction JSBuiltinReducer::ReduceNumberIsInteger(Node* node) {
 // ES6 section 20.1.2.4 Number.isNaN ( number )
 Reduction JSBuiltinReducer::ReduceNumberIsNaN(Node* node) {
   JSCallReduction r(node);
-  if (r.InputsMatchOne(Type::Number())) {
-    // Number.isNaN(a:number) -> BooleanNot(NumberEqual(a, a))
+  // Number.isNaN(a:number) -> ObjectIsNaN(a)
   Node* input = r.GetJSCallInput(0);
-    Node* check = graph()->NewNode(simplified()->NumberEqual(), input, input);
-    Node* value = graph()->NewNode(simplified()->BooleanNot(), check);
+  Node* value = graph()->NewNode(simplified()->ObjectIsNaN(), input);
   return Replace(value);
-  }
-  return NoChange();
 }
 
 // ES6 section 20.1.2.5 Number.isSafeInteger ( number )

src/compiler/js-typed-lowering.cc

@@ -993,12 +993,13 @@ Reduction JSTypedLowering::ReduceJSStrictEqual(Node* node, bool invert) {
   JSBinopReduction r(this, node);
   if (r.left() == r.right()) {
     // x === x is always true if x != NaN
-    if (!r.left_type()->Maybe(Type::NaN())) {
-      Node* replacement = jsgraph()->BooleanConstant(!invert);
+    Node* replacement = graph()->NewNode(simplified()->ObjectIsNaN(), r.left());
+    if (!invert) {
+      replacement = graph()->NewNode(simplified()->BooleanNot(), replacement);
+    }
     ReplaceWithValue(node, replacement);
     return Replace(replacement);
   }
-  }
   if (r.OneInputCannotBe(Type::NumberOrString())) {
     // For values with canonical representation (i.e. neither String, nor
     // Number) an empty type intersection means the values cannot be strictly

src/compiler/opcodes.h

@@ -333,6 +333,7 @@
   V(StoreElement)                   \
   V(StoreTypedElement)              \
   V(ObjectIsDetectableCallable)     \
+  V(ObjectIsNaN)                    \
   V(ObjectIsNonCallable)            \
   V(ObjectIsNumber)                 \
   V(ObjectIsReceiver)               \

src/compiler/simplified-lowering.cc

@@ -2545,6 +2545,35 @@ class RepresentationSelector {
         VisitObjectIs(node, Type::DetectableCallable(), lowering);
         return;
       }
+      case IrOpcode::kObjectIsNaN: {
+        Type* const input_type = GetUpperBound(node->InputAt(0));
+        if (input_type->Is(Type::NaN())) {
+          VisitUnop(node, UseInfo::None(), MachineRepresentation::kBit);
+          if (lower()) {
+            DeferReplacement(node, lowering->jsgraph()->Int32Constant(1));
+          }
+        } else if (!input_type->Maybe(Type::NaN())) {
+          VisitUnop(node, UseInfo::Any(), MachineRepresentation::kBit);
+          if (lower()) {
+            DeferReplacement(node, lowering->jsgraph()->Int32Constant(0));
+          }
+        } else if (input_type->Is(Type::Number())) {
+          VisitUnop(node, UseInfo::TruncatingFloat64(),
+                    MachineRepresentation::kBit);
+          if (lower()) {
+            // ObjectIsNaN(x:kRepFloat64) => Word32Equal(Float64Equal(x,x),#0)
+            Node* const input = node->InputAt(0);
+            node->ReplaceInput(
+                0, jsgraph_->graph()->NewNode(
+                       lowering->machine()->Float64Equal(), input, input));
+            node->AppendInput(jsgraph_->zone(), jsgraph_->Int32Constant(0));
+            NodeProperties::ChangeOp(node, lowering->machine()->Word32Equal());
+          }
+        } else {
+          VisitUnop(node, UseInfo::AnyTagged(), MachineRepresentation::kBit);
+        }
+        return;
+      }
       case IrOpcode::kObjectIsNonCallable: {
         VisitObjectIs(node, Type::NonCallable(), lowering);
         return;

src/compiler/simplified-operator.cc

@@ -475,6 +475,7 @@ UnicodeEncoding UnicodeEncodingOf(const Operator* op) {
   V(TruncateTaggedToWord32, Operator::kNoProperties, 1, 0)       \
   V(TruncateTaggedToFloat64, Operator::kNoProperties, 1, 0)      \
   V(ObjectIsDetectableCallable, Operator::kNoProperties, 1, 0)   \
+  V(ObjectIsNaN, Operator::kNoProperties, 1, 0)                  \
   V(ObjectIsNonCallable, Operator::kNoProperties, 1, 0)          \
   V(ObjectIsNumber, Operator::kNoProperties, 1, 0)               \
   V(ObjectIsReceiver, Operator::kNoProperties, 1, 0)             \

src/compiler/simplified-operator.h

@@ -413,6 +413,7 @@ class V8_EXPORT_PRIVATE SimplifiedOperatorBuilder final
   const Operator* ConvertTaggedHoleToUndefined();
 
   const Operator* ObjectIsDetectableCallable();
+  const Operator* ObjectIsNaN();
   const Operator* ObjectIsNonCallable();
   const Operator* ObjectIsNumber();
   const Operator* ObjectIsReceiver();

src/compiler/typer.cc

@@ -285,6 +285,7 @@ class Typer::Visitor : public Reducer {
 #undef DECLARE_METHOD
 
   static Type* ObjectIsDetectableCallable(Type*, Typer*);
+  static Type* ObjectIsNaN(Type*, Typer*);
   static Type* ObjectIsNonCallable(Type*, Typer*);
   static Type* ObjectIsNumber(Type*, Typer*);
   static Type* ObjectIsReceiver(Type*, Typer*);
@@ -512,6 +513,12 @@ Type* Typer::Visitor::ObjectIsDetectableCallable(Type* type, Typer* t) {
   return Type::Boolean();
 }
 
+Type* Typer::Visitor::ObjectIsNaN(Type* type, Typer* t) {
+  if (type->Is(Type::NaN())) return t->singleton_true_;
+  if (!type->Maybe(Type::NaN())) return t->singleton_false_;
+  return Type::Boolean();
+}
+
 Type* Typer::Visitor::ObjectIsNonCallable(Type* type, Typer* t) {
   if (type->Is(Type::NonCallable())) return t->singleton_true_;
   if (!type->Maybe(Type::NonCallable())) return t->singleton_false_;
@@ -1926,6 +1933,10 @@ Type* Typer::Visitor::TypeObjectIsDetectableCallable(Node* node) {
   return TypeUnaryOp(node, ObjectIsDetectableCallable);
 }
 
+Type* Typer::Visitor::TypeObjectIsNaN(Node* node) {
+  return TypeUnaryOp(node, ObjectIsNaN);
+}
+
 Type* Typer::Visitor::TypeObjectIsNonCallable(Node* node) {
   return TypeUnaryOp(node, ObjectIsNonCallable);
 }

src/compiler/verifier.cc

@@ -954,6 +954,7 @@ void Verifier::Visitor::Check(Node* node) {
       break;
 
     case IrOpcode::kObjectIsDetectableCallable:
+    case IrOpcode::kObjectIsNaN:
     case IrOpcode::kObjectIsNonCallable:
     case IrOpcode::kObjectIsNumber:
     case IrOpcode::kObjectIsReceiver:

test/mjsunit/number-isnan-opt.js

+// Copyright 2017 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.
+
+// Flags: --allow-natives-syntax
+
+(function() {
+  function foo(x) { return Number.isNaN(x); }
+
+  assertTrue(foo(+undefined));
+  assertFalse(foo(undefined));
+  %OptimizeFunctionOnNextCall(foo);
+  assertTrue(foo(+undefined));
+  assertFalse(foo(undefined));
+})();
+
+(function() {
+  function foo(x) { return Number.isNaN(+x); }
+
+  assertTrue(foo(+undefined));
+  assertFalse(foo(0));
+  %OptimizeFunctionOnNextCall(foo);
+  assertTrue(foo(+undefined));
+  assertFalse(foo(0));
+})();
+
+(function() {
+  function foo(x) { return Number.isNaN(x|0); }
+
+  assertFalse(foo(+undefined));
+  assertFalse(foo(0));
+  %OptimizeFunctionOnNextCall(foo);
+  assertFalse(foo(+undefined));
+  assertFalse(foo(0));
+})();
+
+(function() {
+  function foo(x) { return Number.isNaN("" + x); }
+
+  assertFalse(foo(undefined));
+  assertFalse(foo(0));
+  %OptimizeFunctionOnNextCall(foo);
+  assertFalse(foo(undefined));
+  assertFalse(foo(0));
+})();
+
+(function() {
+  function foo(x) { return Number.isNaN(0/0); }
+
+  assertTrue(foo());
+  assertTrue(foo());
+  %OptimizeFunctionOnNextCall(foo);
+  assertTrue(foo());
+  assertTrue(foo());
+})();

test/unittests/compiler/js-builtin-reducer-unittest.cc

@@ -1475,7 +1475,7 @@ TEST_F(JSBuiltinReducerTest, NumberIsNaNWithNumber) {
     Reduction r = Reduce(call);
 
     ASSERT_TRUE(r.Changed());
-    EXPECT_THAT(r.replacement(), IsBooleanNot(IsNumberEqual(p0, p0)));
+    EXPECT_THAT(r.replacement(), IsObjectIsNaN(p0));
   }
 }
 

test/unittests/compiler/node-test-utils.cc

@@ -2348,6 +2348,7 @@ IS_UNOP_MATCHER(NumberToBoolean)
 IS_UNOP_MATCHER(NumberToInt32)
 IS_UNOP_MATCHER(NumberToUint32)
 IS_UNOP_MATCHER(PlainPrimitiveToNumber)
+IS_UNOP_MATCHER(ObjectIsNaN)
 IS_UNOP_MATCHER(ObjectIsReceiver)
 IS_UNOP_MATCHER(ObjectIsSmi)
 IS_UNOP_MATCHER(ObjectIsUndetectable)

test/unittests/compiler/node-test-utils.h

@@ -308,6 +308,7 @@ Matcher<Node*> IsStoreElement(const Matcher<ElementAccess>& access_matcher,
                               const Matcher<Node*>& value_matcher,
                               const Matcher<Node*>& effect_matcher,
                               const Matcher<Node*>& control_matcher);
+Matcher<Node*> IsObjectIsNaN(const Matcher<Node*>& value_matcher);
 Matcher<Node*> IsObjectIsReceiver(const Matcher<Node*>& value_matcher);
 Matcher<Node*> IsObjectIsSmi(const Matcher<Node*>& value_matcher);
 Matcher<Node*> IsObjectIsUndetectable(const Matcher<Node*>& value_matcher);