ufuzz failure

[alexlamsl]

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

function f0(b, c, a) {
    {
        var brake1 = 5;
        do {
            try {
                {
                    var expr3 = --b + a++;
                    for (var key3 in expr3) {
                        c = 1 + c;
                        var arguments = expr3[key3];
                        for (var brake4 = 5; +function Math() {
                            {
                                var brake5 = 5;
                                while (a-- && --brake5 > 0) {
                                    try {
                                        c = c + 1;
                                    } catch (b_1) {
                                        c = 1 + c, c = c + 1, 25 + "foo" << (b_1 && (b_1.c |= 5 ^ 3));
                                        c = 1 + c, (Infinity >= -3) * delete "c" < (38..toString() < null) - ("bar" - "undefined");
                                    }
                                }
                            }
                            {
                                var brake10 = 5;
                                L19289: do {
                                } while (a++ + ((c = c + 1) + (typeof f0 == "function" && --_calls_ >= 0 && f0((c = 1 + c, 
                                (c = c + 1, -0) === [] < -4 === (a && (a.c = "foo" >= "undefined" && 24..toString() >= [ , 0 ][1]))))) || a || 3).toString() && --brake10 > 0);
                            }
                        }() && brake4 > 0; --brake4) {
                            switch (a++ + !function foo_2() {}()) {
                              case (c = c + 1) + b++:
                                {
                                    var Math_2 = function f1(bar) {
                                        c = 1 + c, a && (a[a++ + void b] += 3 >> {} <= ("bar" > 1) != -4 << false << "function" - "undefined");
                                        c = 1 + c, a += (-2 > "bar") * ("c" - 1), (a && (a[c = 1 + c, (undefined * true | (c = c + 1, 
                                        -0)) < ("function" << "bar" & (a && (a[c = 1 + c, a && (a[(c = c + 1) + (typeof f2 == "function" && --_calls_ >= 0 && f2(0, (c = 1 + c, 
                                        -1 / 25 <= "bar" << [] != (c = c + 1, false == 5)), (c = 1 + c, (undefined + "foo" ^ 3 * []) <= (("b", 
                                        undefined) <= (a[c = 1 + c, ((-5 || [ , 0 ].length === 2) != (3 || [])) > ("object" & "") * (24..toString() ^ /[a2][^e]+$/)] = Infinity != 1)))))] = (c = c + 1, 
                                        4) === ("object" || "foo") | (c = c + 1, 24..toString()) << ("number" === "number"))] = [ , 0 ][1] / -2)))] += [] % this)) != +4;
                                    }((c = 1 + c, -0 << this < (-4 > "number") >= ((38..toString() | Infinity) & (Math_2 = "a" >> "c"))), (c = 1 + c, 
                                    25 >>> 4, ~undefined, 3 != 24..toString() != "object" / NaN));
                                }
                                break;

                              case (Math_2 = (c = c + 1, this * 1) && this << -3 << -3 / "function") ? --b + (b |= a) : ~((Math_2 && (Math_2.in += NaN << "c")) === (Math_2 && (Math_2.null = NaN >> "undefined")) | (c = c + 1, 
                                2) * ("a" + 5)):
                                a++ + typeof [ (c = 1 + c, ~("" / -4 % (undefined >= 1))), (c = 1 + c, ((undefined ^ "function") === -5 + 25) / delete (24..toString() & "b")), (c = 1 + c, 
                                ([] != "number" ^ -0 === null) / ([ , 0 ][1] >>> "" >>> (-1 === "b"))), (c = 1 + c, 
                                Math_2 && (Math_2[--b + (typeof f2 == "function" && --_calls_ >= 0 && f2((c = 1 + c, 
                                -4 / 23..toString() % ({} >= "c") & "object" << 22 !== "object" + "c"), 1))] >>= (/[a2][^e]+$/ >>> -3) % (25 ^ null) - (delete 24..toString() !== NaN >> 38..toString()))), (c = 1 + c, 
                                (Math_2 *= ("number", /[a2][^e]+$/) < 25 % -5) != (Math_2 && (Math_2[b = a] &= (38..toString() == null) <= ("bar" | "function")))) ].c;
                                {
                                    var arguments = function a_2(Math_2, b_1) {
                                        c = 1 + c, ([ , 0 ].length === 2 != "bar") >= (NaN >= [ , 0 ][1]) < (1 || -1, 4 % 22);
                                        c = 1 + c, ([] >> null && ("a" && "object")) % ((b_1 += -2 && 38..toString()) >> (25 > 0));
                                    }("a");
                                }
                                break;

                              default:
                              case []:
                                return;
                                {
                                    var brake21 = 5;
                                    do {
                                        for (var brake22 = 5; a++ + ++a && brake22 > 0; --brake22) {
                                        }
                                    } while (--b + (typeof Math_2 == "function" && --_calls_ >= 0 && Math_2()) && --brake21 > 0);
                                }
                                break;
                            }
                        }
                    }
                }
            } catch (c) {
                L19290: for (var brake24 = 5; (Infinity + ([ , 0 ].length === 2) ^ (Math_2 && (Math_2[c = 1 + c, 
                ("foo" != 3) * (undefined >> 22) ^ ~(-1, [])] -= -4 ^ "object"))) % ("undefined" << 3 !== "object" >>> 0) && brake24 > 0; --brake24) {}
                {
                    return Math_2 && Math_2.var;
                }
            } finally {
                for (var brake27 = 5; (b += a) && brake27 > 0; --brake27) {
                    var brake28 = 5;
                    do {
                        {
                            return {
                                Infinity: a++ + ((c = 1 + c, Math_2 && (Math_2[void ((3 & 5) > (Infinity | "b"), 
                                +5 << (24..toString() && "bar"))] = ((22 & this) <= (-1 != -4), {} % "foo" != -1 - Infinity))) || a || 3).toString()
                            };
                        }
                    } while (~((-4 >> "" >= undefined << ([ , 0 ].length === 2)) % ((Math_2 = -3 - 3) % (false * "function"))) && --brake28 > 0);
                }
                {
                    var brake30 = 5;
                    while ([ a++ + {
                        c: !((this << "undefined" ^ 24..toString() * false) <= ("object" * -1 >= (1 & Infinity))),
                        NaN: --b + (b *= a),
                        Infinity: !((-5 < {} ^ (Infinity | false)) / ("c" ^ 23..toString() || -5 < 3))
                    }, typeof f0 == "function" && --_calls_ >= 0 && f0() ].b && --brake30 > 0) {}
                }
            }
        } while ((c = c + 1) + (b = a) && --brake1 > 0);
    }
    try {
        {
            var undefined = typeof Math_2 == "function" && --_calls_ >= 0 && Math_2((c = c + 1) + [ --b + ((c = 1 + c, 
            (c = c + 1, "a") << (Infinity > 23..toString()) == (Math_2 >>= (Math_2 ^= null << "a") || "" ^ "undefined")) || a || 3).toString(), Math_2 ], -5, [ , 0 ][1]);
            for (var brake36 = 5; --b + {
                undefined: void (("a" <= this == -5 > "function") + ("function" + /[a2][^e]+$/ >>> (5, 
                "c"))),
                in: --b + (0 === 1 ? a : b),
                length: (c = c + 1) + function() {}()
            }.var && brake36 > 0; --brake36) {
                {
                    return !([ , 0 ].length === 2 & "object") >>> ("c" << "number" == (undefined ^ []));
                }
                return (c = c + 1) + +b;
                try {
                    break;
                } finally {
                    {
                        var expr42 = (c = 1 + c, (("a", undefined) || undefined << "b") ^ ("b" < "foo") >>> (c = c + 1, 
                        /[a2][^e]+$/));
                        for (var key42 in expr42) {
                            c = 1 + c, "undefined" <= "undefined" | (Math_2 && (Math_2.b = 4 * 22)), 5 + NaN | false - NaN;
                        }
                    }
                    {
                        var expr44 = (c = 1 + c, ((2, "undefined") != 3 < "undefined") % ((c = c + 1, 0) >> ("", 
                        24..toString())));
                        for (var key44 in expr44) {
                            c = 1 + c;
                            var b = expr44[key44];
                            c = 1 + c, ([ , 0 ].length === 2) - "foo" > null << 25 !== -4 > null < (NaN, "");
                        }
                    }
                }
                {
                    L19291: {
                    }
                    for (var brake48 = 5; (c = 1 + c, -23..toString() <= (22 ^ this) == (-2 <= false ^ (undefined ^ NaN))) && brake48 > 0; --brake48) {
                        c = 1 + c, (-4 - 24..toString() ^ (Math_2 %= "foo" << 3)) - (Math_2 && (Math_2[/[abc4]/.test(((c = 1 + c, 
                        (-5 || 2) >> 4 * 23..toString() === ("function" !== 25 == ([ , 0 ][1], 2))) || b || 5).toString())] = (Math_2 && (Math_2.in += [ , 0 ].length === 2 || true)) | ([ , 0 ].length === 2, 
                        undefined)));
                    }
                }
            }
            {
                return;
                --b + a++;
            }
        }
    } catch (foo_2) {
        {
            return --b + (foo_2 <<= a++ + ~(foo_2 && (foo_2[b = a] ^= ({} >> "b" ^ -4 > null) <= (Math_2 && (Math_2.a >>= (24..toString() ^ 4) != +"object")))));
        }
        if (typeof f2 == "function" && --_calls_ >= 0 && f2({
            NaN: 0 === 1 ? a : b,
            0: --b + (a++ + (foo_2 && foo_2.Infinity) ? 0 === 1 ? a : b : ((c = 1 + c, ("c" >> 3 || this >> Infinity) ^ (foo_2 && (foo_2.var = (foo_2 = 38..toString() && 1) != (2 == [ , 0 ][1])))) || a || 3).toString())
        })) {} else {
            var brake54 = 5;
            while (--b + {
                foo: (c = c + 1) + (1 === 1 ? a : b),
                length: --b + (a++ + 23..toString() || 7).toString()[a++ + !b]
            }.foo && --brake54 > 0) {
                if (typeof f0 == "function" && --_calls_ >= 0 && f0(-5)) {
                    try {
                        {
                            var brake57 = 5;
                            L19292: do {
                                var b = foo_2 && foo_2.var, parseInt_1 = a++;
                            } while ((c = c + 1) + +function a_2() {
                                c = 1 + c, 3 !== "undefined" === NaN % 2 && "bar" / -1 - (5 === false);
                                c = 1 + c, (a_2 && (a_2.c = this != "a")) | "bar" & 1 || ("undefined" | 5) << (38..toString() ^ 4);
                                c = 1 + c, (parseInt_1.undefined = (this || -1) & "undefined" !== 1) * ((-0 & 23..toString()) - (null <= "c"));
                            }() && --brake57 > 0);
                        }
                    } catch (a) {
                        L19293: {
                            c = 1 + c, (parseInt_1 && (parseInt_1[c = 1 + c, (5 >>> "foo" < (1 != 3)) % (3 * -5 ^ (-2, 
                            1))] %= (22, 24..toString()))) === 5 < Infinity, NaN * -0 | this > 1;
                            c = 1 + c, (-0 === -3 | {} % -5) >= ("" && 5) + delete 22;
                            c = 1 + c, (undefined & null) >> +25 >= (("object" || []) ^ 4 - NaN);
                        }
                        {
                            c = 1 + c, (-1 * -0, -0 === 3) !== (2 | [ , 0 ][1] || (1, -2));
                            c = 1 + c, ([ , 0 ][1] ^ "bar") >= NaN / [ , 0 ][1] === (5 + 23..toString()) % (Math_2 && (Math_2[c = 1 + c, 
                            (("function" === true) >> (-0 === ([ , 0 ].length === 2))) + "undefined" / 0 * (c = c + 1, 
                            4)] = -5 % -5));
                            c = 1 + c, (parseInt_1 && (parseInt_1[b /= a] ^= ("object", NaN) && (true || -2))) === (foo_2 && (foo_2.var += "bar" === this)) / !undefined;
                        }
                    } finally {
                        if ([ (c = 1 + c, (parseInt_1 && (parseInt_1[[ (c = 1 + c, (undefined < "function" || (c = c + 1, 
                        -1)) - ((3, {}) ^ -3 < 1)), (c = 1 + c, ("object" || null) && 5 + false || void 0 === ("function" || -2)), (c = 1 + c, 
                        Math_2 = - -1 / (-0 < this) === ("number" + -3) / ("object" !== -3)), (c = 1 + c, 
                        [ , 0 ][1] < 23..toString() === "foo" + false && (foo_2 && (foo_2[{
                            set in(parseInt_1) {
                                this.a = [ , 0 ].length === 2 ^ true;
                            },
                            Infinity: (c = 1 + c, delete (-"foo" & 2 === 25)),
                            "": (c = 1 + c, "bar" >= 22 >= "undefined" / NaN & (parseInt_1 && (parseInt_1[--b + (typeof foo_2 == "function" && --_calls_ >= 0 && foo_2(2, Infinity, (c = 1 + c, 
                            ("c", undefined) / ("function" ^ 23..toString()) ^ "foo" * "object" >> (NaN << 38..toString()))))] += (2 >> 1) - (25, 
                            0))))
                        }[c = 1 + c, ("", -4) >>> (false || "a") === (1 === -0) >> "bar" % "function"]] += (-5, 
                        [ , 0 ].length === 2) | (null && /[a2][^e]+$/)))) ].in] = [ , 0 ][1] * NaN * (24..toString() !== []))) == (undefined === null) << 1 * "function") ]) {
                            c = c + 1;
                        } else {
                            return;
                            c = 1 + c, "foo" % "a" < ("" || true) != !2 / ({} >> -1);
                        }
                    }
                }
            }
        }
    }
}

var b = f0();

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

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

function f0(b, c, a) {
    var brake1 = 5;
    do {
        try {
            var expr3 = --b + a++;
            for (var key3 in expr3) {
                c = 1 + c;
                for (var brake4 = 5; +function() {
                    for (var brake5 = 5; a-- && 0 < --brake5; ) {
                        try {
                            c += 1;
                        } catch (b_1) {
                            c = 1 + c, c += 1, b_1 && (b_1.c |= 6), c = 1 + c, 38..toString();
                        }
                    }
                    var brake10 = 5;
                    do {} while (a++ + ((c += 1) + ("function" == typeof f0 && 0 <= --_calls_ && f0((c = 1 + c, 
                    c += 1, -0 === [] < -4 === (a && (a.c = !1))))) || a || 3).toString() && 0 < --brake10);
                }() && 0 < brake4; --brake4) {
                    switch (a++ + !0) {
                      case (c += 1) + b++:
                        var Math_2 = function() {
                            c = 1 + c, a && (a[a++ + void 0] += 3 >> {} <= !1 != -4), c = 1 + c, (a += NaN) && (a[c = 1 + c, 
                            (!0 * undefined | (c += 1, -0)) < (0 & (a && (a[c = 1 + c, a && (a[(c += 1) + ("function" == typeof f2 && 0 <= --_calls_ && f2(0, (c = 1 + c, 
                            -.04 <= "bar" << [] != !1), (undefined + "foo" ^ 3 * []) <= (undefined <= (a[c = 1 + (c = 1 + (c += 1)), 
                            0 * (24..toString() ^ /[a2][^e]+$/) < !0] = !0))))] = "object" === (c += 1, 4) | (c += 1, 
                            24..toString() << !0))] = -0)))] += [] % this);
                        }((c = 1 + c, 38..toString(), Math_2 = 0, c = 1 + c, 24..toString()));
                        break;

                      case c += 1, (Math_2 = +this && this << -3 << NaN) ? --b + (b |= a) : ~((Math_2 && (Math_2.in += 0)) === (Math_2 && (Math_2.null = 0)) | "a5" * (c += 1, 
                        2)):
                        a++, c = 1 + (c = 1 + c), 24..toString(), c = 1 + (c = 1 + c), Math_2 && (Math_2[--b + ("function" == typeof f2 && 0 <= --_calls_ && f2((c = 1 + c, 
                        -4 / 23..toString() % ("c" <= {}) & !0), 1))] >>= 0 - (24..toString(), !0 !== NaN >> 38..toString())), 
                        c = 1 + c, (Math_2 *= !1) && (Math_2[b = a] &= (null == 38..toString()) <= 0);
                        c = 1 + (c = 1 + c), 38..toString();
                        break;

                      default:
                        return;
                    }
                }
            }
        } catch (c) {
            for (var brake24 = 5; (1 / 0 + (2 === [ , 0 ].length) ^ (Math_2 && (Math_2[c = 1 + c, 
            !0 * (undefined >> 22) ^ ~[]] -= -4))) % !1 && 0 < brake24; --brake24) {}
            return Math_2 && Math_2.var;
        } finally {
            for (var brake27 = 5; (b += a) && 0 < brake27; --brake27) {
                var brake28 = 5;
                do {
                    return {
                        Infinity: a++ + (c = 1 + c, Math_2 && (Math_2[void 24..toString()] = {} % "foo" != -1 / 0) || a || 3).toString()
                    };
                } while (~((undefined << (2 === [ , 0 ].length) <= -4) % ((Math_2 = -6) % NaN)) && 0 < --brake28);
            }
            for (var brake30 = 5; [ a++ + {
                c: !((this << "undefined" ^ !1 * 24..toString()) <= !1),
                NaN: --b + (b *= a),
                Infinity: !((-5 < {} ^ 0) / ("c" ^ 23..toString() || !0))
            }, "function" == typeof f0 && 0 <= --_calls_ && f0() ].b && 0 < --brake30; ) {}
        }
    } while ((c += 1) + (b = a) && 0 < --brake1);
    try {
        var undefined = "function" == typeof Math_2 && 0 <= --_calls_ && Math_2((c += 1) + [ --b + (c = 1 + c, 
        c += 1, "a" << (1 / 0 > 23..toString()) == (Math_2 >>= (Math_2 ^= 0) || 0) || a || 3).toString(), Math_2 ], -5, 0), brake36 = 5;
        return --b + {
            undefined: void 0,
            in: --b + b,
            length: (c += 1) + void 0
        }.var && 0 < brake36 ? !(2 === [ , 0 ].length & "object") >>> (0 == (undefined ^ [])) : undefined;
    } catch (foo_2) {
        return --b + (foo_2 << a++ + ~(foo_2 && (foo_2[b = a] ^= ({} >> "b" ^ !1) <= (Math_2 && (Math_2.a >>= NaN != (4 ^ 24..toString()))))));
    }
}

b = f0();

console.log(null, a, b, c, 1 / 0, NaN, void 0);

original result:
null 100 undefined 0 Infinity NaN undefined

uglified result:
null 100 false 0 Infinity NaN undefined

minify(options):
{
  "mangle": false
}

[alexlamsl]

After #3710:

$ uglifyjs test.js -c --reduce-test
// reduce test pass 1, iteration 0: 14109 bytes
// reduce test pass 1, iteration 25: 3626 bytes
// reduce test pass 1, iteration 50: 3404 bytes
// reduce test pass 1, iteration 75: 2785 bytes
// reduce test pass 1, iteration 100: 1017 bytes
// reduce test pass 1, iteration 125: 234 bytes
// reduce test pass 1: 198 bytes
// reduce test pass 2: 181 bytes
// reduce test pass 3: 181 bytes
var a = 0, c = 0;

function f0(b, c, a) {
    try {
        var undefined = 0;
        for (0; (0).var; 0) {
            return 0;
        }
        return;
    } catch (foo_2) {
        if (undefined) {
            0;
        } else {
            c = 0;
        }
    }
}

var b = f0();

console.log(null, a, b, c, Infinity, NaN, undefined);
// output: null 0 undefined 0 Infinity NaN undefined
// minify: null 0 0 0 Infinity NaN undefined
// options: {"compress":true,"mangle":false}