Replaced unary negation by multiplication with -1.

src/x64/full-codegen-x64.cc

Index: src/x64/full-codegen-x64.cc
diff --git a/src/x64/full-codegen-x64.cc b/src/x64/full-codegen-x64.cc
index 1a4abe2bd9dcaca9c665b0322d35f588b2174ad4..68301ec6dca009b87ed04ed7345ac9f8dffee122 100644
--- a/src/x64/full-codegen-x64.cc
+++ b/src/x64/full-codegen-x64.cc
@@ -4335,10 +4335,6 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
       break;
     }
 
-    case Token::SUB:
-      EmitUnaryOperation(expr, "[ UnaryOperation (SUB)");
-      break;
-
     case Token::BIT_NOT:
       EmitUnaryOperation(expr, "[ UnaryOperation (BIT_NOT)");
       break;
@@ -4351,6 +4347,7 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
 
 void FullCodeGenerator::EmitUnaryOperation(UnaryOperation* expr,
                                            const char* comment) {
+  ASSERT_EQ(Token::BIT_NOT, expr->op());
   // TODO(svenpanne): Allowing format strings in Comment would be nice here...
   Comment cmt(masm_, comment);
   UnaryOpStub stub(expr->op());