2077020 - [loong64] Implement constant RHS specialization for WASM SIMD comparisons

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, task)

Description

[Rong Bao [:csmantle]]

Loong64 LSX has immediate comparison instructions, for example VSEQI.[BHDW]. These instruction splats the sign- or zero-extended immediate to all lanes as RHS, then perform the comparison. These can elide one vector value materialization when applicable.

Comment 1

[Rong Bao [:csmantle]]

Attachment: Bug 2077020 - Part 1: Introduce SimdConstant::splatIntValue() to extract splatted integer values. r=#spidermonkey-reviewers!

Comment 2

[Rong Bao [:csmantle]]

Attachment: Bug 2077020 - [loong64] Part 2: Introduce LSX compare instructions with immediate RHS. r=#spidermonkey-reviewers!

This includes the following instructions:

• VSEQI.[BHWD]
• VS{LE,LT}I.[BHWD]{,U}

Comment 3

[Rong Bao [:csmantle]]

Attachment: Bug 2077020 - [loong64] Part 3: Implement compareInt{8x16,16x8,32x4,64x2} with SimdConstant rhs. r=#spidermonkey-reviewers!

These masm methods emits VS{EQ,LE,LT}I.* when possible, otherwise fall
back to the loadConstantSimd128() and reg-reg compare methods.

Comment 4

[Rong Bao [:csmantle]]

Attachment: Bug 2077020 - [loong64] Part 4: Enable const RHS specialization for applicable WASM SIMD compare ops. r=#spidermonkey-reviewers!

Comment 5

[Rong Bao [:csmantle]]

The effect of this stack is as follows. This WAT module:

(module
  (memory 1)
  (func (export "f")
    (v128.store (i32.const 32)
      (i32x4.lt_s (v128.load (i32.const 0)) (v128.const i32x4 5 5 5 5)))))

... compiles to the following native code before this stack:

[...]
vld          $vr0, $s7, 0
vldi         $vr1, 0x805
vslt.w       $vr0, $vr0, $vr1
vst          $vr0, $s7, 32
[...]

... while it compiles to this after the stack:

[...]
vld          $vr0, $s7, 0
vslti.w      $vr0, $vr0, 5
vst          $vr0, $s7, 32
[...]

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/d0f18859d99e
https://hg.mozilla.org/integration/autoland/rev/12ce49174bb2
Revert "Bug 2077020 - [loong64] Part 4: Enable const RHS specialization for applicable WASM SIMD compare ops. r=yury" for causing linting failures @IonTypes.h.

Comment 7

[agoloman]

Backed out for causing linting failures @IonTypes.h.

• Backout link
• Push with failures
• Failure Log

Comment 8

[Rong Bao [:csmantle]]

This looks trivial to fix. The problem is that when I switched from std::optional to mozilla::Maybe, I didn't remove the header inclusion.

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/5b33955c6780
https://hg.mozilla.org/integration/autoland/rev/82d7a581de8f
Part 1: Introduce SimdConstant::splatIntValue() to extract splatted integer values. r=yury
https://github.com/mozilla-firefox/firefox/commit/3a3255e6473d
https://hg.mozilla.org/integration/autoland/rev/4c50de45ab36
[loong64] Part 2: Introduce LSX compare instructions with immediate RHS. r=yury
https://github.com/mozilla-firefox/firefox/commit/44f70b6e77d3
https://hg.mozilla.org/integration/autoland/rev/4011fb8ab706
[loong64] Part 3: Implement compareInt{8x16,16x8,32x4,64x2} with SimdConstant rhs. r=yury
https://github.com/mozilla-firefox/firefox/commit/5320dd8219ad
https://hg.mozilla.org/integration/autoland/rev/14723ea5c6f2
[loong64] Part 4: Enable const RHS specialization for applicable WASM SIMD compare ops. r=yury

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/77bc6deb2fcc
https://hg.mozilla.org/mozilla-central/rev/fade3dffbde4
Part 1: Introduce SimdConstant::splatIntValue() to extract splatted integer values. r=yury
https://github.com/mozilla-firefox/firefox/commit/faa491daa654
https://hg.mozilla.org/mozilla-central/rev/50838e3ec5da
[loong64] Part 2: Introduce LSX compare instructions with immediate RHS. r=yury
https://github.com/mozilla-firefox/firefox/commit/e357ad5755e3
https://hg.mozilla.org/mozilla-central/rev/ac0abda237ac
[loong64] Part 3: Implement compareInt{8x16,16x8,32x4,64x2} with SimdConstant rhs. r=yury

Comment 11

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/82d7a581de8f
https://hg.mozilla.org/mozilla-central/rev/4c50de45ab36
https://hg.mozilla.org/mozilla-central/rev/4011fb8ab706
https://hg.mozilla.org/mozilla-central/rev/14723ea5c6f2