Reverted some code which got accidentally committed as part of another commit.

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 4619 matching lines @@
   HValue* value = Pop();
   HInstruction* instr = new(zone()) HMul(value, graph_->GetConstant1());
   ast_context()->ReturnInstruction(instr, expr->id());
 }
 
 
 void HGraphBuilder::VisitSub(UnaryOperation* expr) {
   CHECK_ALIVE(VisitForValue(expr->expression()));
   HValue* value = Pop();
   HInstruction* instr = new(zone()) HMul(value, graph_->GetConstantMinus1());
-
-  Representation rep = ToRepresentation(oracle()->UnaryType(expr));
-  AssumeRepresentation(instr, rep);
-
   ast_context()->ReturnInstruction(instr, expr->id());
 }
 
 
 void HGraphBuilder::VisitBitNot(UnaryOperation* expr) {
   CHECK_ALIVE(VisitForValue(expr->expression()));
   HValue* value = Pop();
   HInstruction* instr = new(zone()) HBitNot(value);
   ast_context()->ReturnInstruction(instr, expr->id());
 }
@@ skipping 1463 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify();
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal