[turbofan] Only consider inhabited types for constant folding in typed lowering.

src/compiler/js-typed-lowering.cc

 // 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.
 
 #include "src/code-factory.h"
 #include "src/compilation-dependencies.h"
 #include "src/compiler/access-builder.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/js-typed-lowering.h"
 #include "src/compiler/linkage.h"
@@ skipping 1831 matching lines @@
   return NoChange();
 }
 
 
 Reduction JSTypedLowering::Reduce(Node* node) {
   // Check if the output type is a singleton.  In that case we already know the
   // result value and can simply replace the node if it's eliminable.
   if (!NodeProperties::IsConstant(node) && NodeProperties::IsTyped(node) &&
       node->op()->HasProperty(Operator::kEliminatable)) {
     Type* upper = NodeProperties::GetType(node);
-    if (upper->IsConstant()) {
-      Node* replacement = jsgraph()->Constant(upper->AsConstant()->Value());
-      ReplaceWithValue(node, replacement);
-      return Changed(replacement);
-    } else if (upper->Is(Type::MinusZero())) {
-      Node* replacement = jsgraph()->Constant(factory()->minus_zero_value());
-      ReplaceWithValue(node, replacement);
-      return Changed(replacement);
-    } else if (upper->Is(Type::NaN())) {
-      Node* replacement = jsgraph()->NaNConstant();
-      ReplaceWithValue(node, replacement);
-      return Changed(replacement);
-    } else if (upper->Is(Type::Null())) {
-      Node* replacement = jsgraph()->NullConstant();
-      ReplaceWithValue(node, replacement);
-      return Changed(replacement);
-    } else if (upper->Is(Type::PlainNumber()) && upper->Min() == upper->Max()) {
-      Node* replacement = jsgraph()->Constant(upper->Min());
-      ReplaceWithValue(node, replacement);
-      return Changed(replacement);
-    } else if (upper->Is(Type::Undefined())) {
-      Node* replacement = jsgraph()->UndefinedConstant();
-      ReplaceWithValue(node, replacement);
-      return Changed(replacement);
+    if (upper->IsInhabited()) {
+      if (upper->IsConstant()) {
+        Node* replacement = jsgraph()->Constant(upper->AsConstant()->Value());
+        ReplaceWithValue(node, replacement);
+        return Changed(replacement);
+      } else if (upper->Is(Type::MinusZero())) {
+        Node* replacement = jsgraph()->Constant(factory()->minus_zero_value());
+        ReplaceWithValue(node, replacement);
+        return Changed(replacement);
+      } else if (upper->Is(Type::NaN())) {
+        Node* replacement = jsgraph()->NaNConstant();
+        ReplaceWithValue(node, replacement);
+        return Changed(replacement);
+      } else if (upper->Is(Type::Null())) {
+        Node* replacement = jsgraph()->NullConstant();
+        ReplaceWithValue(node, replacement);
+        return Changed(replacement);
+      } else if (upper->Is(Type::PlainNumber()) &&
+                 upper->Min() == upper->Max()) {
+        Node* replacement = jsgraph()->Constant(upper->Min());
+        ReplaceWithValue(node, replacement);
+        return Changed(replacement);
+      } else if (upper->Is(Type::Undefined())) {
+        Node* replacement = jsgraph()->UndefinedConstant();
+        ReplaceWithValue(node, replacement);
+        return Changed(replacement);
+      }
     }
   }
   switch (node->opcode()) {
     case IrOpcode::kJSEqual:
       return ReduceJSEqual(node, false);
     case IrOpcode::kJSNotEqual:
       return ReduceJSEqual(node, true);
     case IrOpcode::kJSStrictEqual:
       return ReduceJSStrictEqual(node, false);
     case IrOpcode::kJSStrictNotEqual:
@@ skipping 121 matching lines @@
 }
 
 
 CompilationDependencies* JSTypedLowering::dependencies() const {
   return dependencies_;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8