Use typefeedback for bitwise operations....

src/hydrogen.cc

 // Copyright 2011 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 4802 matching lines @@
   // for a smi operation. If one of the operands is a constant string
   // do not generate code assuming it is a smi operation.
   if (info.IsSmi() &&
       ((left->IsConstant() && HConstant::cast(left)->HasStringValue()) ||
        (right->IsConstant() && HConstant::cast(right)->HasStringValue()))) {
     return instr;
   }
   if (FLAG_trace_representation) {
     PrintF("Info: %s/%s\n", info.ToString(), ToRepresentation(info).Mnemonic());
   }
-  AssumeRepresentation(instr, ToRepresentation(info));
+  Representation rep = ToRepresentation(info);
+  // We only generate either int32 or generic tagged bitwise operations.
+  if (instr->IsBitwiseBinaryOperation() && rep.IsDouble()) {
+    rep = Representation::Integer32();
+  }
+  AssumeRepresentation(instr, rep);
   return instr;
 }
 
 
 // Check for the form (%_ClassOf(foo) === 'BarClass').
 static bool IsClassOfTest(CompareOperation* expr) {
   if (expr->op() != Token::EQ_STRICT) return false;
   CallRuntime* call = expr->left()->AsCallRuntime();
   if (call == NULL) return false;
   Literal* literal = expr->right()->AsLiteral();
@@ skipping 60 matching lines @@
 
 void HGraphBuilder::AssumeRepresentation(HValue* value, Representation r) {
   if (value->CheckFlag(HValue::kFlexibleRepresentation)) {
     if (FLAG_trace_representation) {
       PrintF("Assume representation for %s to be %s (%d)\n",
              value->Mnemonic(),
              r.Mnemonic(),
              graph_->GetMaximumValueID());
     }
     value->ChangeRepresentation(r);
-    // The representation of the value is dictated by type feedback.
+    // The representation of the value is dictated by type feedback and
+    // will not be changed later.
     value->ClearFlag(HValue::kFlexibleRepresentation);
   } else if (FLAG_trace_representation) {
     PrintF("No representation assumed\n");
   }
 }
 
 
 Representation HGraphBuilder::ToRepresentation(TypeInfo info) {
   if (info.IsSmi()) return Representation::Integer32();
   if (info.IsInteger32()) return Representation::Integer32();
@@ skipping 952 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify();
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal