Invalid output when using binary operations using SIMPLE_OPTIMIZATIONS

[brainexe]

I found an issue with "simple" compression and binary "or" operations. In this case, the variable is just overwritten with "48" instead of doing clean "or" operations on given input.
With advanced compression (or just whitespace removal) I get valid code.

Input code: (generated by https://github.com/openfl/lime convertor)

var addFlags = function(data) {
    data.flags = (data.flags |= 8) | 4
    data.flags = (data.flags |= 16) | 32
}

var data = {flags:1};
addFlags(data)
console.log(data.flags); // expected: 61

Output in SIMPLE_OPTIMIZATIONS

var addFlags = function(a) {
  a.flags = 12;
  a.flags = 48;
}, data = {flags:1};
addFlags(data);
console.log(data.flags);

-> output 48 👎

Output in ADVANCED_OPTIMIZATIONS

var addFlags = function(a) {
  a.flags |= 12;
  a.flags |= 48;
};
var b = {flags:1};
addFlags(b);
console.log(b.flags);

-> output: 61 👍

Playground: https://closure-compiler.appspot.com/home#code%3D%252F%252F%2520%253D%253DClosureCompiler%253D%253D%250A%252F%252F%2520%2540compilation_level%2520SIMPLE_OPTIMIZATIONS%250A%252F%252F%2520%2540formatting%2520pretty_print%250A%252F%252F%2520%253D%253D%252FClosureCompiler%253D%253D%250A%250Avar%2520addFlags%2520%253D%2520function(data)%2520%257B%250A%2520%2520%2520%2520data.flags%2520%253D%2520(data.flags%2520%257C%253D%25208)%2520%257C%25204%250A%2520%2520%2520%2520data.flags%2520%253D%2520(data.flags%2520%257C%253D%252016)%2520%257C%252032%250A%257D%250A%250Avar%2520data%2520%253D%2520%257Bflags%253A1%257D%253B%250AaddFlags(data)%250Aconsole.log(data.flags)%253B

[lauraharker]

Thanks for the report.

With just enabling DeadAssignmentElimination and RemoveUnusedVariables in the debugger, I get this output:

var addFlags = function(data) {
  data.flags = 8 | 4;
  data.flags = 16 | 32;
};
var data = {flags:1};
addFlags(data);
console.log(data.flags);

Looks like the DeadPropertyAssignmentElimination pass handles assignment operations like +=, |= etc incorrectly.

This doesn't happen in ADVANCED mode because another pass replaces data.flags |= 8 with data.flags = data.flags | 8 before the DeadPropertyAssignmentElimination pass runs.

debugger

[lauraharker]

Submitted a fix for this internally