Desugar bitwise negation into XOR and kill all UnaryOp stuff.

src/ast.cc

Index: src/ast.cc
diff --git a/src/ast.cc b/src/ast.cc
index f99eaef40f048974d1fbf9246ac8b04aef757333..2077f87d74153ba31e6fc94250a89508c3aeddda 100644
--- a/src/ast.cc
+++ b/src/ast.cc
@@ -304,16 +304,6 @@ void UnaryOperation::RecordToBooleanTypeFeedback(TypeFeedbackOracle* oracle) {
 }
 
 
-bool UnaryOperation::ResultOverwriteAllowed() {
-  switch (op_) {
-    case Token::BIT_NOT:
-      return true;
-    default:
-      return false;
-  }
-}
-
-
 void BinaryOperation::RecordToBooleanTypeFeedback(TypeFeedbackOracle* oracle) {
   // TODO(olivf) If this Operation is used in a test context, then the right
   // hand side has a ToBoolean stub and we want to collect the type information.