[turbofan] Optimize strict equality with unique input.

If one input to JSStrictEqual/JSNotStrictEqual is Unique (except
InternalizedString) or the hole, then we can turn that into a
direct pointer comparison, as such values are only equal to exactly
the same unique value.

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

Review-Url: https://codereview.chromium.org/2611363002
Cr-Commit-Position: refs/heads/master@{#42122}

src/compiler/js-typed-lowering.cc

@@ -494,8 +494,6 @@ JSTypedLowering::JSTypedLowering(Editor* editor,
       dependencies_(dependencies),
       flags_(flags),
       jsgraph_(jsgraph),
-      the_hole_type_(
-          Type::HeapConstant(factory()->the_hole_value(), graph()->zone())),
       type_cache_(TypeCache::Get()) {
   for (size_t k = 0; k < arraysize(shifted_int32_ranges_); ++k) {
     double min = kMinInt / (1 << k);
@@ -954,25 +952,10 @@ Reduction JSTypedLowering::ReduceJSStrictEqual(Node* node, bool invert) {
   Reduction const reduction = ReduceJSEqualTypeOf(node, invert);
   if (reduction.Changed()) return reduction;
 
-  if (r.OneInputIs(the_hole_type_)) {
-    return r.ChangeToPureOperator(simplified()->ReferenceEqual(), invert);
-  }
-  if (r.OneInputIs(Type::Undefined())) {
-    return r.ChangeToPureOperator(simplified()->ReferenceEqual(), invert);
-  }
-  if (r.OneInputIs(Type::Null())) {
-    return r.ChangeToPureOperator(simplified()->ReferenceEqual(), invert);
-  }
-  if (r.OneInputIs(Type::Boolean())) {
-    return r.ChangeToPureOperator(simplified()->ReferenceEqual(), invert);
-  }
-  if (r.OneInputIs(Type::Object())) {
-    return r.ChangeToPureOperator(simplified()->ReferenceEqual(), invert);
-  }
-  if (r.OneInputIs(Type::Receiver())) {
+  if (r.BothInputsAre(Type::Unique())) {
     return r.ChangeToPureOperator(simplified()->ReferenceEqual(), invert);
   }
-  if (r.BothInputsAre(Type::Unique())) {
+  if (r.OneInputIs(Type::NonStringUniqueOrHole())) {
     return r.ChangeToPureOperator(simplified()->ReferenceEqual(), invert);
   }
   if (r.IsInternalizedStringCompareOperation()) {

src/compiler/js-typed-lowering.h

@@ -96,7 +96,6 @@ class V8_EXPORT_PRIVATE JSTypedLowering final
   Flags flags_;
   JSGraph* jsgraph_;
   Type* shifted_int32_ranges_[4];
-  Type* const the_hole_type_;
   TypeCache const& type_cache_;
 };
 

src/compiler/types.h

@@ -173,6 +173,8 @@ namespace compiler {
   V(StringOrReceiver,           kString | kReceiver) \
   V(Unique,                     kBoolean | kUniqueName | kNull | kUndefined | \
                                 kReceiver) \
+  V(NonStringUniqueOrHole,      kBoolean | kHole | kNull | kReceiver | \
+                                kSymbol | kUndefined) \
   V(Internal,                   kHole | kExternalPointer | kOtherInternal) \
   V(NonInternal,                kPrimitive | kReceiver) \
   V(NonNumber,                  kUnique | kString | kInternal) \