[turbofan] Infer proper type for calls to Date.now.

src/compiler/type-cache.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_TYPE_CACHE_H_
 #define V8_COMPILER_TYPE_CACHE_H_
 
 #include "src/compiler/types.h"
 #include "src/date.h"
 
@@ skipping 79 matching lines @@
   Type* const kJSArrayLengthType = Type::Unsigned32();
 
   // The JSTyped::length property always contains a tagged number in the range
   // [0, kMaxSmiValue].
   Type* const kJSTypedArrayLengthType = Type::UnsignedSmall();
 
   // The String::length property always contains a smi in the range
   // [0, String::kMaxLength].
   Type* const kStringLengthType = CreateRange(0.0, String::kMaxLength);
 
+  // A time value always contains a tagged number in the range
+  // [-kMaxTimeInMs, kMaxTimeInMs].
+  Type* const kTimeValueType =
+      CreateRange(-DateCache::kMaxTimeInMs, DateCache::kMaxTimeInMs);
+
   // The JSDate::day property always contains a tagged number in the range
   // [1, 31] or NaN.
   Type* const kJSDateDayType =
       Type::Union(CreateRange(1, 31.0), Type::NaN(), zone());
 
   // The JSDate::hour property always contains a tagged number in the range
   // [0, 23] or NaN.
   Type* const kJSDateHourType =
       Type::Union(CreateRange(0, 23.0), Type::NaN(), zone());
 
   // The JSDate::minute property always contains a tagged number in the range
   // [0, 59] or NaN.
   Type* const kJSDateMinuteType =
       Type::Union(CreateRange(0, 59.0), Type::NaN(), zone());
 
   // The JSDate::month property always contains a tagged number in the range
   // [0, 11] or NaN.
   Type* const kJSDateMonthType =
       Type::Union(CreateRange(0, 11.0), Type::NaN(), zone());
 
   // The JSDate::second property always contains a tagged number in the range
   // [0, 59] or NaN.
   Type* const kJSDateSecondType = kJSDateMinuteType;
 
   // The JSDate::value property always contains a tagged number in the range
   // [-kMaxTimeInMs, kMaxTimeInMs] or NaN.
-  Type* const kJSDateValueType = Type::Union(
-      CreateRange(-DateCache::kMaxTimeInMs, DateCache::kMaxTimeInMs),
-      Type::NaN(), zone());
+  Type* const kJSDateValueType =
+      Type::Union(kTimeValueType, Type::NaN(), zone());
 
   // The JSDate::weekday property always contains a tagged number in the range
   // [0, 6] or NaN.
   Type* const kJSDateWeekdayType =
       Type::Union(CreateRange(0, 6.0), Type::NaN(), zone());
 
   // The JSDate::year property always contains a tagged number in the signed
   // small range or NaN.
   Type* const kJSDateYearType =
       Type::Union(Type::SignedSmall(), Type::NaN(), zone());
@@ skipping 10 matching lines @@
   }
 
   Zone* zone() { return &zone_; }
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_TYPE_CACHE_H_