Don't ignore the actual input representation in UnaryMathOperations

src/hydrogen-instructions.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 3050 matching lines @@
 HType HBitNot::CalculateInferredType() {
   return HType::TaggedNumber();
 }
 
 
 HType HUnaryMathOperation::CalculateInferredType() {
   return HType::TaggedNumber();
 }
 
 
+Representation HUnaryMathOperation::RepresentationFromInputs() {
+  Representation rep = representation();
+  // If any of the actual input representation is more general than what we
+  // have so far but not Tagged, use that representation instead.
+  Representation input_rep = value()->representation();
+  if (!input_rep.IsTagged()) rep = rep.generalize(input_rep);
+  return rep;
+}
+
+
 HType HStringCharFromCode::CalculateInferredType() {
   return HType::String();
 }
 
 
 HType HAllocate::CalculateInferredType() {
   return type_;
 }
 
 
@@ skipping 723 matching lines @@
     case kBackingStore:
       if (!name_.is_null()) stream->Add(*String::cast(*name_)->ToCString());
       stream->Add("[backing-store]");
       break;
   }
 
   stream->Add("@%d", offset());
 }
 
 } }  // namespace v8::internal