Better codegen for '<expression> === void <literal>'.

src/ia32/full-codegen-ia32.cc

Index: src/ia32/full-codegen-ia32.cc
diff --git a/src/ia32/full-codegen-ia32.cc b/src/ia32/full-codegen-ia32.cc
index f46a30a5e29ff2e03008ddb204d2df391cda85ae..ecb2c9001c3524746aea18b2ec3525b99f07773e 100644
--- a/src/ia32/full-codegen-ia32.cc
+++ b/src/ia32/full-codegen-ia32.cc
@@ -3930,25 +3930,13 @@ void FullCodeGenerator::VisitForTypeofValue(Expression* expr) {
 }
 
 
-bool FullCodeGenerator::TryLiteralCompare(Token::Value op,
-                                          Expression* left,
-                                          Expression* right,
-                                          Label* if_true,
-                                          Label* if_false,
-                                          Label* fall_through) {
-  if (op != Token::EQ && op != Token::EQ_STRICT) return false;
-
-  // Check for the pattern: typeof <expression> == <string literal>.
-  Literal* right_literal = right->AsLiteral();
-  if (right_literal == NULL) return false;
-  Handle<Object> right_literal_value = right_literal->handle();
-  if (!right_literal_value->IsString()) return false;
-  UnaryOperation* left_unary = left->AsUnaryOperation();
-  if (left_unary == NULL || left_unary->op() != Token::TYPEOF) return false;
-  Handle<String> check = Handle<String>::cast(right_literal_value);
-
+void FullCodeGenerator::EmitLiteralCompareTypeof(Expression* expr,
+                                                 Handle<String> check,
+                                                 Label* if_true,
+                                                 Label* if_false,
+                                                 Label* fall_through) {
   { AccumulatorValueContext context(this);
-    VisitForTypeofValue(left_unary->expression());
+    VisitForTypeofValue(expr);
   }
   PrepareForBailoutBeforeSplit(TOS_REG, true, if_true, if_false);
 
@@ -3998,8 +3986,20 @@ bool FullCodeGenerator::TryLiteralCompare(Token::Value op,
   } else {
     if (if_false != fall_through) __ jmp(if_false);
   }
+}
+
 
-  return true;
+void FullCodeGenerator::EmitLiteralCompareUndefined(Expression* expr,
+                                                    Label* if_true,
+                                                    Label* if_false,
+                                                    Label* fall_through) {
+  { AccumulatorValueContext context(this);

[fschneider, 2011/06/21 11:36:08]

Same comment as on ARM.

[Steven, 2011/06/22 10:00:53]

Done.

+    VisitForTypeofValue(expr);
+  }
+  PrepareForBailoutBeforeSplit(TOS_REG, true, if_true, if_false);
+
+  __ cmp(eax, isolate()->factory()->undefined_value());
+  Split(equal, if_true, if_false, fall_through);
 }