Use type feedback for unary minus, improving the performance on e.g. 3d-cube by

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 4612 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());
+  TypeInfo info = oracle()->UnaryType(expr);
+  Representation rep = ToRepresentation(info);
+  TraceRepresentation(expr->op(), info, instr, rep);
+  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 1489 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify();
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal