ufuzz failure

[alexlamsl]

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

function f0(a) {
    function f1(undefined, undefined, bar_2) {
        for (var brake1 = 5; --b + {
            Infinity: --b,
            in: [][c = 1 + c, ("object" << "a" >>> (c = c + 1, 25)) / ((bar_2 && (bar_2.in += "object" + NaN)) << ("object" < "number"))],
            undefined: {
                0: (c = 1 + c, (null % -2 ^ 25 - "function") <= (-3 & -3) % (undefined >>> -3)),
                "\t": (c = 1 + c, ({} > 23..toString() & -0 <= Infinity) - (("bar" | 3) << void /[a2][^e]+$/)),
                "\t": (c = 1 + c, (0 << 2 ^ "object" >= 22) % (undefined >>> 3 && (0, -4)))
            }.Infinity,
            3: (c = 1 + c, bar_2 && (bar_2[function a_1() {
                c = 1 + c, (24..toString() % 2 || -0 + 25) & ("" ^ /[a2][^e]+$/) % (-4 >> "function");
                c = 1 + c, ((1 | [ , 0 ].length === 2) == ([ , 0 ].length === 2) * "number") >= (23..toString() > 5, 
                a_1 && (a_1[c = 1 + c, (a_1 && (a_1.c += -4 >> ([ , 0 ].length === 2) & "undefined" === "b")) !== delete (NaN != 2)] = undefined != 3));
                c = 1 + c, (a_1 && (a_1[--b + +a] -= ("undefined" ^ true) >= (0 || -4))) << (c = c + 1, 
                3) - (25 >> "a");
            }] += ((bar_2 &= true > 3) == (-4 & "undefined")) % (bar_2 = ("function" & "number", 
            bar_2 && (bar_2.a >>>= "foo" ^ 0)))))
        } && brake1 > 0; --brake1) {
            L10214: {
                {
                    var brake7 = 5;
                    while ((c = 1 + c, (Infinity * 22 === true > -0) >= (c = c + 1, true > -2)) && --brake7 > 0) {
                        c = 1 + c, (24..toString() | 5) * ([] || "") % (undefined >> 23..toString() >> ("object" >> 24..toString()));
                    }
                }
                switch (c = 1 + c, (4 & 22) / (bar_2 && (bar_2.b = undefined + -0)) >> ("" & "c" & (bar_2 && (bar_2[c = 1 + c, 
                ((false & "undefined") >>> "a" + 2) - ((1 ^ -5) & this * 24..toString())] = null - -2)))) {
                  default:
                    ;

                  case c = 1 + c, -5 >> null > ([] != 23..toString()) < (-5 < NaN > (bar_2 && (bar_2.null <<= "function" != "number"))):
                    ;
                    break;

                  case c = 1 + c, Infinity * 23..toString() === NaN >>> -4 === (bar_2 %= (-5 != 1) << ([] == this)):
                    ;
                    break;

                  case c = 1 + c, (-4 <= 24..toString() && "c" ^ true) & NaN % this / (bar_2 /= 3 | "function"):
                    ;
                    break;
                }
                c = 1 + c, (bar_2 && (bar_2.c += (38..toString() ^ -5) > "b" >>> "undefined")) <= (c = c + 1, 
                -0 >> 25);
            }
        }
        if (~(("b" || 4) <= (24..toString() !== -3) && (bar_2 && (bar_2.var = undefined % "bar" ^ false >> ([ , 0 ].length === 2))))) {
            var expr12 = [ (c = 1 + c, "bar" !== this != (24..toString() ^ -2) ^ ~-1 !== (c = c + 1, 
            1)), (c = 1 + c, (-0 < true & -1 >>> {}) >= delete (undefined || 2)), (c = 1 + c, 
            (/[a2][^e]+$/ | [ , 0 ].length === 2) - (/[a2][^e]+$/ - 4) <= (c = c + 1, 4 ^ true)), (c = 1 + c, 
            (c = c + 1, "object" / 24..toString()) - (false % "undefined" >> (-0 >> -1))), (c = 1 + c, 
            a_2 += (({} | 3) == (24..toString() == -2)) * (("undefined" && [ , 0 ][1]) !== (undefined ^ -5))) ];
            for (var key12 in expr12) {
                c = 1 + c;
                var a_2 = expr12[key12];
            }
        } else {
            return a++ + /[abc4]/.test(([ , (c = 1 + c, 24..toString() > "function" >= -2 >>> 3 <= ("c" ^ 1) - (25 & "foo")), (c = 1 + c, 
            "number" >> "c" << -4 * ([ , 0 ].length === 2) != (([ , 0 ].length === 2) - null & (-2 & "c"))) ] || b || 5).toString());
        }
    }
    var c = f1(false, "", {
        3: --b + (a && a.in)
    }.a);
}

var b_2 = f0(typeof b--, b_2 = [ b_2 ], (c = c + 1) + (true <= "a" == (this ^ 3) != (b_2 && (b_2.c <<= (undefined, 
-5))) << "foo" / undefined));

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

// uglified code
// (beautified)
var o, e, s = 10;

o = typeof s--, [ f ].c <<= -5, e = function(n, n, i) {
    for (var a = 5; --s + {
        Infinity: --s,
        in: [][e = 1 + e, (0 >>> (e += 1, 25)) / ((i && (i.in += "objectNaN")) << !1)],
        undefined: {
            0: 0 <= -3 % (n >>> -3),
            "\t": 0 % (n >>> 3 && -4)
        }.Infinity,
        3: (e = 1 + (1 + (1 + (1 + e))), i && (i[function i() {
            i[e = 1 + (1 + (1 + e)), !0 !== (i.c += 0)] = 3 != n, e = 1 + e, i[--s + +o] -= !0, 
            e += 1;
        }] += (0 == (i &= !1)) % (i = i && (i.a >>>= 0))))
    } && 0 < a; --a) {
        switch (e = 1 + ((e = 1 + e) + 1), 4 / (i && (i.b = n + -0)) >> (0 & (i && (i[e = 1 + e, 
        0 - (-6 & "24" * this)] = 2)))) {
          default:
          case e = 1 + e, !1 < ((i && (i.null <<= !0)) < !1):
          case e = 1 + e, !1 === (i %= !0 << ([] == this)):
          case e = 1 + e, 1 & NaN % this / (i /= 3):
        }
        e = 1 + e, i && (i.c += !1), e += 1;
    }
    var t = [ "bar" !== this != -26 ^ !0, !0, !1, NaN, (e = 1 + ((e = 1 + ((e = 1 + (1 + ((e = 1 + e) + 1))) + 1)) + 1), 
    f += !1 * (0 != (-5 ^ n))) ];
    for (var c in t) {
        e = 1 + e;
        var f = t[c];
    }
}(!1, "", {
    3: --s + (o && o.in)
}.a), console.log(null, 100, s, 1, 1 / 0, NaN, void 0);

original result:
null 100 -4 1 Infinity NaN undefined

uglified result:
evalmachine.<anonymous>:1
(function(){var o,e,s=10;o=typeof s--,[f].c<<=-5,e=function(n,n,i){for(var a=5;--s+{Infinity:--s,in:[][e=1+e,(0>>>(e+=1,25))/((i&&(i.in+="objectNaN"))<<!1)],undefined:{0:0<=-3%(n>>>-3),"\t":0%(n>>>3&&-4)}.Infinity,3:(e=1+(1+(1+(1+e))),i&&(i[function i(){i[e=1+(1+(1+e)),!0!==(i.c+=0)]=3!=n,e=1+e,i[--s+ +o]-=!0,e+=1}]+=(0==(i&=!1))%(i=i&&(i.a>>>=0))))}&&0<a;--a){switch(e=1+((e=1+e)+1),4/(i&&(i.b=n+-0))>>(0&(i&&(i[e=1+e,0-(-6&"24"*this)]=2)))){default:case e=1+e,!1<((i&&(i.null<<=!0))<!1):case e=1+e,!1===(i%=!0<<([]==this)):case e=1+e,1&NaN%this/(i/=3):}e=1+e,i&&(i.c+=!1),e+=1}var t=["bar"!==this!=-26^!0,!0,!1,NaN,(e=1+((e=1+((e=1+(1+((e=1+e)+1)))+1))+1),f+=!1*(0!=(-5^n)))];for(var c in t){e=1+e;var f=t[c]}}(!1,"",{3:--s+(o&&o.in)}.a),console.log(null,100,s,1,1/0,NaN,void 0);})()
                                       ^

ReferenceError: f is not defined
    at evalmachine.<anonymous>:1:40
    at evalmachine.<anonymous>:1:786
minify(options):
{
  "compress": {
    "passes": 1000000,
    "unsafe": true
  },
  "toplevel": true
}