[crankshaft] Use canonical nan_value or minus_zero_value objects instead of constant heap numbers w…

src/crankshaft/hydrogen-instructions.cc

Index: src/crankshaft/hydrogen-instructions.cc
diff --git a/src/crankshaft/hydrogen-instructions.cc b/src/crankshaft/hydrogen-instructions.cc
index 9947dee6d4b4a172c0c1abf5b317e53d1f5d5d6a..b8020c727064914dae35b8478b9be95be8bbee8b 100644
--- a/src/crankshaft/hydrogen-instructions.cc
+++ b/src/crankshaft/hydrogen-instructions.cc
@@ -2172,6 +2172,32 @@ HConstant::HConstant(Handle<Object> object, Representation r)
           BooleanValueField::encode(object->BooleanValue()) |
           IsUndetectableField::encode(false) | IsCallableField::encode(false) |
           InstanceTypeField::encode(kUnknownInstanceType)) {
+  if (object->IsNumber()) {
+    double n = object->Number();
+    bool has_int32_value = IsInteger32(n);
+    bit_field_ = HasInt32ValueField::update(bit_field_, has_int32_value);
+    int32_value_ = DoubleToInt32(n);
+    bit_field_ = HasSmiValueField::update(
+        bit_field_, has_int32_value && Smi::IsValid(int32_value_));
+    if (std::isnan(n)) {
+      double_value_ = std::numeric_limits<double>::quiet_NaN();
+      // Canonicalize object with NaN value.
+      DCHECK(object->IsHeapObject());  // NaN can't be a Smi.
+      Isolate* isolate = HeapObject::cast(*object)->GetIsolate();
+      object = isolate->factory()->nan_value();
+      object_ = Unique<Object>::CreateUninitialized(object);
+    } else {
+      double_value_ = n;
+      // Canonicalize object with -0.0 value.
+      if (bit_cast<int64_t>(n) == bit_cast<int64_t>(-0.0)) {
+        DCHECK(object->IsHeapObject());  // -0.0 can't be a Smi.
+        Isolate* isolate = HeapObject::cast(*object)->GetIsolate();
+        object = isolate->factory()->minus_zero_value();
+        object_ = Unique<Object>::CreateUninitialized(object);
+      }
+    }
+    bit_field_ = HasDoubleValueField::update(bit_field_, true);
+  }
   if (object->IsHeapObject()) {
     Handle<HeapObject> heap_object = Handle<HeapObject>::cast(object);
     Isolate* isolate = heap_object->GetIsolate();
@@ -2187,20 +2213,6 @@ HConstant::HConstant(Handle<Object> object, Representation r)
         bit_field_,
         HasMapValue() && Handle<Map>::cast(heap_object)->is_stable());
   }
-  if (object->IsNumber()) {
-    double n = object->Number();
-    bool has_int32_value = IsInteger32(n);
-    bit_field_ = HasInt32ValueField::update(bit_field_, has_int32_value);
-    int32_value_ = DoubleToInt32(n);
-    bit_field_ = HasSmiValueField::update(
-        bit_field_, has_int32_value && Smi::IsValid(int32_value_));
-    if (std::isnan(n)) {
-      double_value_ = std::numeric_limits<double>::quiet_NaN();
-    } else {
-      double_value_ = n;
-    }
-    bit_field_ = HasDoubleValueField::update(bit_field_, true);
-  }
 
   Initialize(r);
 }