[crankshaft] Eliminate unnecessary ToNumber call

src/crankshaft/hydrogen.cc

 // Copyright 2013 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/crankshaft/hydrogen.h"
 
 #include <memory>
 #include <sstream>
 
 #include "src/allocation-site-scopes.h"
@@ skipping 2253 matching lines @@
     Push(Add<HCallRuntime>(
             Runtime::FunctionForId(Runtime::kNumberToStringSkipCache),
             1));
   }
   if_found.End();
 
   return Pop();
 }
 
 HValue* HGraphBuilder::BuildToNumber(HValue* input) {
-  if (input->type().IsTaggedNumber()) {
+  if (input->type().IsTaggedNumber() ||
+      input->representation().IsSpecialization()) {
     return input;
   }
   Callable callable = CodeFactory::ToNumber(isolate());
   HValue* stub = Add<HConstant>(callable.code());
   HValue* values[] = {context(), input};
   HCallWithDescriptor* instr = Add<HCallWithDescriptor>(
       stub, 0, callable.descriptor(), ArrayVector(values));
   instr->set_type(HType::TaggedNumber());
   return instr;
 }
@@ skipping 11110 matching lines @@
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 }  // namespace internal
 }  // namespace v8