Add support for unary plus in hydrogen compiler.

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 4501 matching lines @@
 
       HBasicBlock* join =
           CreateJoin(materialize_false, materialize_true, expr->id());
       set_current_block(join);
       ast_context()->ReturnValue(Pop());
     } else {
       ASSERT(ast_context()->IsEffect());
       VisitForEffect(expr->expression());
     }
 
-  } else if (op == Token::BIT_NOT || op == Token::SUB) {
+  } else {
     VISIT_FOR_VALUE(expr->expression());
     HValue* value = Pop();
     HInstruction* instr = NULL;
     switch (op) {
       case Token::BIT_NOT:
         instr = new HBitNot(value);
         break;
       case Token::SUB:
-        instr = new HMul(graph_->GetConstantMinus1(), value);
+        instr = new HMul(value, graph_->GetConstantMinus1());
+        break;
+      case Token::ADD:
+        instr = new HMul(value, graph_->GetConstant1());
+        break;
+      case Token::TYPEOF:
+        instr = new HTypeof(value);
         break;
       default:
-        UNREACHABLE();
+        BAILOUT("Value: unsupported unary operation");
         break;
     }
     ast_context()->ReturnInstruction(instr, expr->id());
-  } else if (op == Token::TYPEOF) {
-    VISIT_FOR_VALUE(expr->expression());
-    HValue* value = Pop();
-    ast_context()->ReturnInstruction(new HTypeof(value), expr->id());
-  } else {
-    BAILOUT("Value: unsupported unary operation");
   }
 }
 
 
 void HGraphBuilder::VisitIncrementOperation(IncrementOperation* expr) {
   // IncrementOperation is never visited by the visitor. It only
   // occurs as a subexpression of CountOperation.
   UNREACHABLE();
 }
 
@@ skipping 1352 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify();
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal