[turbofan] Optimize typeof o === "object" checks.

src/compiler/typer.cc

Index: src/compiler/typer.cc
diff --git a/src/compiler/typer.cc b/src/compiler/typer.cc
index c08e62cd3ac4e765b41aae0880c627dc1067ac4e..0802c3aebacf587f14bf33758316f5347b4bf933 100644
--- a/src/compiler/typer.cc
+++ b/src/compiler/typer.cc
@@ -284,6 +284,7 @@ class Typer::Visitor : public Reducer {
 #undef DECLARE_METHOD
 
   static Type* ObjectIsCallable(Type*, Typer*);
+  static Type* ObjectIsNonCallable(Type*, Typer*);
   static Type* ObjectIsNumber(Type*, Typer*);
   static Type* ObjectIsReceiver(Type*, Typer*);
   static Type* ObjectIsSmi(Type*, Typer*);
@@ -502,8 +503,14 @@ Type* Typer::Visitor::ToString(Type* type, Typer* t) {
 // Type checks.
 
 Type* Typer::Visitor::ObjectIsCallable(Type* type, Typer* t) {
-  if (type->Is(Type::Function())) return t->singleton_true_;
-  if (type->Is(Type::Primitive())) return t->singleton_false_;
+  if (type->Is(Type::Callable())) return t->singleton_true_;

[bakkot1, 2017/01/23 19:26:16]

Drive-by comment: document.all is "callable", in that `document.all()` succeeds
(and the 'Callable' type in types.h includes 'kOtherUndetectable', which I'm
guessing is the type of document.all), but `typeof document.all === 'function'`
should evaluate to false. At a glance it looks like this might cause it to
evaluate to true.

[Benedikt Meurer, 2017/02/14 10:18:24]

Aye, sorry for the delay, just discovered this comment. Can you file a bug
report please?

+  if (!type->Maybe(Type::Callable())) return t->singleton_false_;
+  return Type::Boolean();
+}
+
+Type* Typer::Visitor::ObjectIsNonCallable(Type* type, Typer* t) {
+  if (type->Is(Type::NonCallable())) return t->singleton_true_;
+  if (!type->Maybe(Type::NonCallable())) return t->singleton_false_;
   return Type::Boolean();
 }
 
@@ -1828,6 +1835,10 @@ Type* Typer::Visitor::TypeObjectIsCallable(Node* node) {
   return TypeUnaryOp(node, ObjectIsCallable);
 }
 
+Type* Typer::Visitor::TypeObjectIsNonCallable(Node* node) {
+  return TypeUnaryOp(node, ObjectIsNonCallable);
+}
+
 Type* Typer::Visitor::TypeObjectIsNumber(Node* node) {
   return TypeUnaryOp(node, ObjectIsNumber);
 }