Generate faster compares for === and !== with boolean constants.

src/hydrogen.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 6154 matching lines @@
 static bool IsLiteralCompareNil(HValue* left,
                                 Token::Value op,
                                 HValue* right,
                                 Handle<Object> nil,
                                 HValue** expr) {
   return MatchLiteralCompareNil(left, op, right, nil, expr) ||
       MatchLiteralCompareNil(right, op, left, nil, expr);
 }
 
 
+static bool IsLiteralCompareBool(HValue* left,
+                                 Token::Value op,
+                                 HValue* right) {
+  return op == Token::EQ_STRICT &&
+      ((left->IsConstant() && HConstant::cast(left)->handle()->IsBoolean()) ||
+       (right->IsConstant() && HConstant::cast(right)->handle()->IsBoolean()));
+}
+
+
 void HGraphBuilder::VisitCompareOperation(CompareOperation* expr) {
   ASSERT(!HasStackOverflow());
   ASSERT(current_block() != NULL);
   ASSERT(current_block()->HasPredecessor());
   if (IsClassOfTest(expr)) {
     CallRuntime* call = expr->left()->AsCallRuntime();
     ASSERT(call->arguments()->length() == 1);
     CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));
     HValue* value = Pop();
     Literal* literal = expr->right()->AsLiteral();
@@ skipping 27 matching lines @@
     return HandleLiteralCompareTypeof(expr, typeof_expr, check);
   }
   HValue* sub_expr = NULL;
   Factory* f = graph()->isolate()->factory();
   if (IsLiteralCompareNil(left, op, right, f->undefined_value(), &sub_expr)) {
     return HandleLiteralCompareNil(expr, sub_expr, kUndefinedValue);
   }
   if (IsLiteralCompareNil(left, op, right, f->null_value(), &sub_expr)) {
     return HandleLiteralCompareNil(expr, sub_expr, kNullValue);
   }
+  if (IsLiteralCompareBool(left, op, right)) {
+    HCompareObjectEqAndBranch* result =
+        new(zone()) HCompareObjectEqAndBranch(left, right);
+    result->set_position(expr->position());
+    return ast_context()->ReturnControl(result, expr->id());
+  }
 
   if (op == Token::INSTANCEOF) {
     // Check to see if the rhs of the instanceof is a global function not
     // residing in new space. If it is we assume that the function will stay the
     // same.
     Handle<JSFunction> target = Handle<JSFunction>::null();
     VariableProxy* proxy = expr->right()->AsVariableProxy();
     bool global_function = (proxy != NULL) && proxy->var()->IsUnallocated();
     if (global_function &&
         info()->has_global_object() &&
@@ skipping 1161 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify(false);  // No full verify.
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal