var commutativeOperators = makePredicate("== === != !== * & | ^");
OPT(AST_Binary, function(self, compressor){
- function reverse(op) {
- if (!(self.left.has_side_effects() || self.right.has_side_effects())) {
+ function reverse(op, force) {
+ if (force || !(self.left.has_side_effects() || self.right.has_side_effects())) {
if (op) self.operator = op;
var tmp = self.left;
self.left = self.right;
if (commutativeOperators(self.operator)) {
if (self.right instanceof AST_Constant
&& !(self.left instanceof AST_Constant)) {
- reverse();
+ // if right is a constant, whatever side effects the
+ // left side might have could not influence the
+ // result. hence, force switch.
+ reverse(null, true);
}
}
self = self.lift_sequences(compressor);
// XXX: intentionally falling down to the next case
case "==":
case "!=":
- if (compressor.option("unsafe")
- && self.left instanceof AST_UnaryPrefix
- && self.left.operator == "typeof"
- && self.right instanceof AST_String
- && self.right.value == "undefined") {
- if (!(self.left.expression instanceof AST_SymbolRef)
- || !self.left.expression.undeclared()) {
- self.left = self.left.expression;
- self.right = make_node(AST_Undefined, self.left).optimize(compressor);
+ if (self.left instanceof AST_String
+ && self.left.value == "undefined"
+ && self.right instanceof AST_UnaryPrefix
+ && self.right.operator == "typeof"
+ && compressor.option("unsafe")) {
+ if (!(self.right.expression instanceof AST_SymbolRef)
+ || !self.right.expression.undeclared()) {
+ self.right = self.right.expression;
+ self.left = make_node(AST_Undefined, self.left).optimize(compressor);
if (self.operator.length == 2) self.operator += "=";
}
}
comparisons: true
};
input: { a = typeof b.c != "undefined" }
- expect: { a = typeof b.c != "undefined" }
+ expect: { a = "undefined" != typeof b.c }
}
typeof_eq_undefined_unsafe: {
unsafe: true
};
input: { a = typeof b.c != "undefined" }
- expect: { a = b.c !== void 0 }
+ expect: { a = void 0 !== b.c }
+}
+
+typeof_eq_undefined_unsafe2: {
+ options = {
+ comparisons: true,
+ unsafe: true
+ };
+ input: { a = "undefined" != typeof b.c }
+ expect: { a = void 0 !== b.c }
}