Drop null/undefined check if we already check for IsUndetectable in BuildCompareNil

src/crankshaft/hydrogen.cc

 // Copyright 2013 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.
 
 #include "src/crankshaft/hydrogen.h"
 
 #include <sstream>
 
 #include "src/allocation-site-scopes.h"
 #include "src/ast/ast-numbering.h"
@@ skipping 669 matching lines @@
 
 HConstant* HGraph::GetConstantMinus1() {
   return GetConstant(&constant_minus1_, -1);
 }
 
 
 HConstant* HGraph::GetConstantBool(bool value) {
   return value ? GetConstantTrue() : GetConstantFalse();
 }
 
+#define DEFINE_GET_CONSTANT(Name, name, type, htype, boolean_value,         \
+                            undetectable)                                   \
+  HConstant* HGraph::GetConstant##Name() {                                  \
+    if (!constant_##name##_.is_set()) {                                     \
+      HConstant* constant = new (zone()) HConstant(                         \
+          Unique<Object>::CreateImmovable(                                  \
+              isolate()->factory()->name##_value()),                        \
+          Unique<Map>::CreateImmovable(isolate()->factory()->type##_map()), \
+          false, Representation::Tagged(), htype, true, boolean_value,      \
+          undetectable, ODDBALL_TYPE);                                      \
+      constant->InsertAfter(entry_block()->first());                        \
+      constant_##name##_.set(constant);                                     \
+    }                                                                       \
+    return ReinsertConstantIfNecessary(constant_##name##_.get());           \
+  }
 
-#define DEFINE_GET_CONSTANT(Name, name, type, htype, boolean_value)            \
-HConstant* HGraph::GetConstant##Name() {                                       \
-  if (!constant_##name##_.is_set()) {                                          \
-    HConstant* constant = new(zone()) HConstant(                               \
-        Unique<Object>::CreateImmovable(isolate()->factory()->name##_value()), \
-        Unique<Map>::CreateImmovable(isolate()->factory()->type##_map()),      \
-        false,                                                                 \
-        Representation::Tagged(),                                              \
-        htype,                                                                 \
-        true,                                                                  \
-        boolean_value,                                                         \
-        false,                                                                 \
-        ODDBALL_TYPE);                                                         \
-    constant->InsertAfter(entry_block()->first());                             \
-    constant_##name##_.set(constant);                                          \
-  }                                                                            \
-  return ReinsertConstantIfNecessary(constant_##name##_.get());                \
-}
-
-
-DEFINE_GET_CONSTANT(Undefined, undefined, undefined, HType::Undefined(), false)
-DEFINE_GET_CONSTANT(True, true, boolean, HType::Boolean(), true)
-DEFINE_GET_CONSTANT(False, false, boolean, HType::Boolean(), false)
-DEFINE_GET_CONSTANT(Hole, the_hole, the_hole, HType::None(), false)
-DEFINE_GET_CONSTANT(Null, null, null, HType::Null(), false)
-
+DEFINE_GET_CONSTANT(Undefined, undefined, undefined, HType::Undefined(), false,
+                    true)
+DEFINE_GET_CONSTANT(True, true, boolean, HType::Boolean(), true, false)
+DEFINE_GET_CONSTANT(False, false, boolean, HType::Boolean(), false, false)
+DEFINE_GET_CONSTANT(Hole, the_hole, the_hole, HType::None(), false, false)
+DEFINE_GET_CONSTANT(Null, null, null, HType::Null(), false, true)
 
 #undef DEFINE_GET_CONSTANT
 
 #define DEFINE_IS_CONSTANT(Name, name)                                         \
 bool HGraph::IsConstant##Name(HConstant* constant) {                           \
   return constant_##name##_.is_set() && constant == constant_##name##_.get();  \
 }
 DEFINE_IS_CONSTANT(Undefined, undefined)
 DEFINE_IS_CONSTANT(0, 0)
 DEFINE_IS_CONSTANT(1, 1)
@@ skipping 2445 matching lines @@
   BuildCopyElements(boilerplate_elements, kind, elements,
                     kind, length, NULL);
   return result;
 }
 
 
 void HGraphBuilder::BuildCompareNil(HValue* value, Type* type,
                                     HIfContinuation* continuation,
                                     MapEmbedding map_embedding) {
   IfBuilder if_nil(this);
-  bool some_case_handled = false;
-  bool some_case_missing = false;
-
-  if (type->Maybe(Type::Null())) {
-    if (some_case_handled) if_nil.Or();
-    if_nil.If<HCompareObjectEqAndBranch>(value, graph()->GetConstantNull());
-    some_case_handled = true;
-  } else {
-    some_case_missing = true;
-  }
-
-  if (type->Maybe(Type::Undefined())) {
-    if (some_case_handled) if_nil.Or();
-    if_nil.If<HCompareObjectEqAndBranch>(value,
-                                         graph()->GetConstantUndefined());
-    some_case_handled = true;
-  } else {
-    some_case_missing = true;
-  }
 
   if (type->Maybe(Type::Undetectable())) {
-    if (some_case_handled) if_nil.Or();
     if_nil.If<HIsUndetectableAndBranch>(value);
-    some_case_handled = true;
   } else {
-    some_case_missing = true;
-  }
+    bool maybe_null = type->Maybe(Type::Null());
+    if (maybe_null) {
+      if_nil.If<HCompareObjectEqAndBranch>(value, graph()->GetConstantNull());
+    }
 
-  if (some_case_missing) {
+    if (type->Maybe(Type::Undefined())) {
+      if (maybe_null) if_nil.Or();
+      if_nil.If<HCompareObjectEqAndBranch>(value,
+                                           graph()->GetConstantUndefined());
+    }
+
     if_nil.Then();
     if_nil.Else();
+
     if (type->NumClasses() == 1) {
       BuildCheckHeapObject(value);
       // For ICs, the map checked below is a sentinel map that gets replaced by
       // the monomorphic map when the code is used as a template to generate a
       // new IC. For optimized functions, there is no sentinel map, the map
       // emitted below is the actual monomorphic map.
       if (map_embedding == kEmbedMapsViaWeakCells) {
         HValue* cell =
             Add<HConstant>(Map::WeakCellForMap(type->Classes().Current()));
         HValue* expected_map = Add<HLoadNamedField>(
@@ skipping 10425 matching lines @@
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 }  // namespace internal
 }  // namespace v8