ufuzz failure

[alexlamsl]

// original code
// (beautified)
var _calls_ = 10, a = 100, b = 10, c = 0;

function f0(a, b) {
    {
        var foo = function f1(b) {
            a;
            if (a++ + (a && (a[(c = c + 1) + a] = (a = 4 >>> -1 < (-5 < 3)) > ((-2 ^ null) == /[a2][^e]+$/ >>> 25)))) {
                c = c + 1;
            }
        }();
    }
    return a && typeof a.NaN == "function" && --_calls_ >= 0 && a.NaN(1, 25, --b + {
        "": /[abc4]/.test(((c = c + 1) + b++ || b || 5).toString()),
        0: --b + [ --b + ((a && (a.Infinity += "b" >= ([ , 0 ].length === 2))) <= ~[ , 0 ][1] & undefined > -1 === (-0 ^ 0)), (c = c + 1) + b--, (c = c + 1) + 1, delete a, typeof f1 == "function" && --_calls_ >= 0 && f1(undefined, (c = 1 + c, 
        a && (a[delete (a && (a[{
            NaN: (c = 1 + c, true < 0 >= -0 >> "bar" ^ (4 !== null) >>> (Infinity && this)),
            in: (c = 1 + c, a = ("foo" ^ [ , 0 ].length === 2) + false / "number" >> (c = c + 1, 
            "bar") % (/[a2][^e]+$/ ^ -5)),
            length: (c = 1 + c, (c = c + 1, a = 25 !== undefined) <= (a && (a[c = 1 + c, ((38..toString() & 4) != (-3 != [ , 0 ][1])) >> (/[a2][^e]+$/ / null <= (a && (a[c = 1 + c, 
            (-1 == 23..toString() && (a && (a[c = 1 + c, (a && (a.in += "a" % 2)) > "foo" % false < ("" == [] | (24..toString() && 5))] /= 38..toString() < 3))) * (/[a2][^e]+$/ >= Infinity === ("bar" || 0))] = 1 << 2)))] += ("b", 
            false))) % ("object" == [ , 0 ][1])),
            3: (c = 1 + c, (a && (a[c = 1 + c, -4 >= ([ , 0 ].length === 2) == -2 >> -5 && (23..toString(), 
            NaN) ^ -undefined] = "object" >= -1)) << (c = c + 1, "undefined") >> ("a" > /[a2][^e]+$/ === (c = c + 1, 
            [ , 0 ].length === 2))),
            b: (c = 1 + c, a && (a[--b + a--] = ("" != 38..toString()) >>> (22 == "function") << ((3 && 22) ^ /[a2][^e]+$/ - undefined)))
        }[+function bar() {
        }()]] += (22 ^ "object") >= -5 - "foo" === ("object" ^ 0 | this >= -2)))] = a && (a[--b + ~a] += ("foo" == "foo") << ([ , 0 ].length === 2 == -3)) && (a && (a.null = /[a2][^e]+$/ / 23..toString() >> (c = c + 1, 
        Infinity))))), (c = 1 + c, (this <= "foo") * ("c" != ([ , 0 ].length === 2)) == (5 == [ , 0 ][1] !== -1 * 38..toString()))) ].foo,
        3: void ((1 ^ -4) === (a && (a.a /= 38..toString() >>> 22)), 1 != 3 & (a && (a.undefined = true * 24..toString()))),
        in: null,
        "": a && typeof a.c == "function" && --_calls_ >= 0 && a.c("a", "object")
    });
}

var NaN = f0();

console.log(null, a, b, c, Infinity, NaN, undefined);

// uglified code
// (beautified)
var i = 10, t = 0;

!function(o, n) {
    o++ + (o && (o[(t += 1) + o] = !1 < (o = !0))) && (t += 1), o && "function" == typeof o.NaN && 0 <= --i && o.NaN(1, 25, --n + {
        "": /[abc4]/.test("" + ((t += 1) + n++ || n || 5)),
        0: --n + [ --n + ((o && (o.Infinity += !1)) <= -1 & !1), (t += 1) + n--, (t += 1) + 1, delete o, "function" == typeof f1 && 0 <= --i && f1(void 0, (t = 1 + t, 
        o && (o[o && (o[[ !0 ^ !0 >>> this, o = 0, (o = !0)[t = 1 + ((t = 1 + ((t = 1 + (1 + t)) + 1)) + 1), 
        !0 >> (NaN <= (o && (o[t = 1 + t, 0] = 4)))] += !1, (t = 1 + t, o && (o[t = 1 + t, 
        !1] = !1), t += 1, t += 1), (t = 1 + t, o && (o[--n + o--] = 1 << 22)) ][0]] += !1 === (0 | -2 <= this)), 
        !0] = o && (o[--n + ~o] += 1) && o && (o.null = NaN >> (t += 1, 1 / 0)))), (t = 1 + t, 
        !0 * (this <= "foo") == 1)) ].foo,
        3: (o && (o.a /= 0), void (o && (o.undefined = 24))),
        in: null,
        "": o && "function" == typeof o.c && 0 <= --i && o.c("a", "object")
    });
}(), console.log(null, 100, 10, t, 1 / 0, void 0, void 0);


original result:
null 100 10 0 Infinity NaN undefined

uglified result:
null 100 10 0 Infinity undefined undefined

// reduced test case (output will differ)

// (beautified)
function f0(a) {
    console.log(a++);
    return a && this;
}

var NaN = f0();

console.log(NaN);
// output: NaN
// NaN
// 
// minify: NaN
// undefined
// 
// options: {
//   "compress": {
//     "passes": 1000000,
//     "unsafe": true
//   },
//   "toplevel": true
// }

minify(options):
{
  "compress": {
    "passes": 1000000,
    "unsafe": true
  },
  "toplevel": true
}

Suspicious compress options:
  evaluate
  passes
  reduce_vars
  sequences
  unsafe
  unused

Suspicious options:
  toplevel