1688828 - Optimize TypedArray length with double result

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, task, P3)

Description

[Jan de Mooij [:jandem]]

Fast path support for length > INT32_MAX shouldn't be too hard to implement on top of bug 1687441.

We should probably do the same for the byteOffset and ArrayBuffer byteLength intrinsics, although those are likely less hot.

Comment 1

[Jan de Mooij [:jandem]]

I have some patches for this. For a simple micro-benchmark (see below) summing a 5 GB Int8Array I get:

before: 82 seconds
after:  11 seconds

We're not hoisting the bounds check inside the loop and ideally the JIT backend would replace the floating point instructions with IntPtr/Int64 ones, but for now this naive approach should be good enough.

function f(ta) {
    var res = 0;
    for (var i = 0; i < ta.length; i++) {
        res += ta[i];
    }
    return res;
}
var ta = new Int8Array(5 * 1024 * 1024 * 1024);
for (var i = 0; i < ta.length; i += 2048) {
    ta[i] = 1; // Ensure pages are allocated.
}
var t = new Date;
var sum = f(ta);
print(new Date - t);
print(sum);

Comment 2

[Jan de Mooij [:jandem]]

Attachment: Bug 1688828 part 1 - Rename loadArrayBufferViewLengthPtr to loadArrayBufferViewLengthIntPtr. r?anba!

This seems clearer now that we use IntPtr in more places.

Comment 3

[Jan de Mooij [:jandem]]

Attachment: Bug 1688828 part 2 - Optimize typed array length with double result in CacheIR. r?anba!

Depends on D104993

Comment 4

[Jan de Mooij [:jandem]]

Attachment: Bug 1688828 part 3 - Transpile LoadTypedArrayLengthDoubleResult in Warp. r?anba!

Depends on D104994

Comment 5

[Jan de Mooij [:jandem]]

Attachment: Bug 1688828 part 4 - Optimize TypedArrayByteOffset with double result in CacheIR. r?anba!

Depends on D104995

Comment 6

[Jan de Mooij [:jandem]]

Attachment: Bug 1688828 part 5 - Change MArrayBufferViewByteOffset to return IntPtr instead of Int32. r?anba!

This matches MArrayBufferViewLength.

Depends on D104996

Comment 7

[Jan de Mooij [:jandem]]

Attachment: Bug 1688828 part 6 - Transpile TypedArrayByteOffsetDoubleResult in Warp. r?anba!

Depends on D104997

Comment 8

[Jan de Mooij [:jandem]]

Attachment: Bug 1688828 part 7 - Optimize ArrayBufferByteLength with double result in CacheIR. r?anba!

Depends on D104998

Comment 9

[Jan de Mooij [:jandem]]

Attachment: Bug 1688828 part 8 - Rename MArrayBufferByteLengthInt32, change to return IntPtr instead of Int32. r?anba!

Depends on D104999

Comment 10

[Jan de Mooij [:jandem]]

Attachment: Bug 1688828 part 9 - Transpile LoadArrayBufferByteLengthDoubleResult in Warp. r?anba!

Depends on D105001

Comment 11

[Jan de Mooij [:jandem]]

Attachment: Bug 1688828 part 10 - Replace loadArrayBuffer*Int32 with guardNonNegativeIntPtrToInt32. r?anba!

This is simpler and shorter, and it's now easier to see that CacheIR and Warp do
the same thing because they call the same MacroAssembler methods.

On 64-bit platforms, IC code now checks for large lengths also when large ArrayBuffers
are disabled. Warp is already doing that for MNonNegativeIntPtrToInt32.

Depends on D105003

Comment 12

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/087a29c7f317
part 1 - Rename loadArrayBufferViewLengthPtr to loadArrayBufferViewLengthIntPtr. r=anba
https://hg.mozilla.org/integration/autoland/rev/6b9201d64b9d
part 2 - Optimize typed array length with double result in CacheIR. r=anba
https://hg.mozilla.org/integration/autoland/rev/16a6532aae9d
part 3 - Transpile LoadTypedArrayLengthDoubleResult in Warp. r=anba
https://hg.mozilla.org/integration/autoland/rev/a454b82b3448
part 4 - Optimize TypedArrayByteOffset with double result in CacheIR. r=anba
https://hg.mozilla.org/integration/autoland/rev/1797f3729257
part 5 - Change MArrayBufferViewByteOffset to return IntPtr instead of Int32. r=anba
https://hg.mozilla.org/integration/autoland/rev/d30c7aaa28bd
part 6 - Transpile TypedArrayByteOffsetDoubleResult in Warp. r=anba
https://hg.mozilla.org/integration/autoland/rev/cb2c05fdafa9
part 7 - Optimize ArrayBufferByteLength with double result in CacheIR. r=anba
https://hg.mozilla.org/integration/autoland/rev/664569686223
part 8 - Rename MArrayBufferByteLengthInt32, change to return IntPtr instead of Int32. r=anba
https://hg.mozilla.org/integration/autoland/rev/1d9276690933
part 9 - Transpile LoadArrayBufferByteLengthDoubleResult in Warp. r=anba
https://hg.mozilla.org/integration/autoland/rev/7cc18ce3b9a2
part 10 - Replace loadArrayBuffer*Int32 with guardNonNegativeIntPtrToInt32. r=anba

Comment 13

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/087a29c7f317
https://hg.mozilla.org/mozilla-central/rev/6b9201d64b9d
https://hg.mozilla.org/mozilla-central/rev/16a6532aae9d
https://hg.mozilla.org/mozilla-central/rev/a454b82b3448
https://hg.mozilla.org/mozilla-central/rev/1797f3729257
https://hg.mozilla.org/mozilla-central/rev/d30c7aaa28bd
https://hg.mozilla.org/mozilla-central/rev/cb2c05fdafa9
https://hg.mozilla.org/mozilla-central/rev/664569686223
https://hg.mozilla.org/mozilla-central/rev/1d9276690933
https://hg.mozilla.org/mozilla-central/rev/7cc18ce3b9a2