766218 - IonMonkey: Make "value === boolean" fast

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Jan de Mooij [:jandem]]

JM has a fast path for this and we need it for V8 earley-boyer.

A micro-benchmark:
--
function f() {
    var a = [{}, true];
    var res = 0;

    for (var i=0; i<10000000; i++) {
        if (a[i & 1] !== false)
            res += 1;
    }
    print(res);
}

var t = new Date;
f();
print(new Date - t);
--
JM+TI :  22 ms
Ion   : 170 ms

Comment 1

[Jan de Mooij [:jandem]]

Attachment: Patch

I tried to use MCompare with different LIR instructions, but adding MCompareConstant seemed a bit simpler. The patch also has a few minor, unrelated MCompare changes.

On earley-boyer, this seems to get rid of all calls to StrictlyEqual<false> (!==). There are still some stub calls left for the === in sc_assq, one of the operands there has type "int or string".

Comment 2

[Jan de Mooij [:jandem]]

Attachment: Patch

Fixes a small perf issue.

Comment 3

[David Anderson [:dvander] - inactive, e-mail if emergency]

This is about a 15% perf win on earley-boyer on my machine - nice! Will review tonight.

Comment 4

[Jan de Mooij [:jandem]]

Attachment: Patch

Different approach, applies on top of bug 768027.

Comment 5

[Jan de Mooij [:jandem]]

https://hg.mozilla.org/projects/ionmonkey/rev/82120910b08f