742034 - IonMonkey: Compile JSOP_THIS hard case

Status: RESOLVED WORKSFORME

(Core :: JavaScript Engine, defect)

Description

[Hannes Verschore [:h4writer]]

According to AWFY we are still slower on SS 3d-cube. I reduced it to the following code:

function CreateP(X, Y, Z) {
    this.V = [X, Y, Z, 1];
}
function Init(CubeSize) {
    for (var i = 0; i < 320000; i++)
        CreateP(0, 0, 0);
}
Init()

IM: 768ms
JM+TI: 177ms
V8: 177ms

Haven't look into the cause yet.

Comment 1

[Hannes Verschore [:h4writer]]

The slowdown is because JSOP_THIS isn't supported in globalFrame yet. We bailout, so the function CreateP never gets compiled.

Comment 2

[Hannes Verschore [:h4writer]]

Or I wasn't awake when I reported this, or there were some changes. Because now it bails in JSOP_THIS the hard case. (What is more understandable. I was already puzzled how this could hit global frame)

Even more reduced is the following testcase. Where the reason of performance loss is clearly the JSOP_THIS and not the array init.

function CreateP() {
    this.V = 1
}
function Init(CubeSize) {
    for (var i = 0; i < 320000; i++)
        CreateP();
}
Init()

JM+TI: 13ms
V8:    47ms
IM:    99ms

Comment 3

[Hannes Verschore [:h4writer]]

JM and IM now have the same performance