1685708 - Add inlining support for BigInt.as{Int,Uint}N

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, enhancement)

Description

[André Bargull [:anba]]

Add inlining support for BigInt.as{Int,Uint}N() to improve the performance when using BigInt for int64 operations. Inlining support more than doubles our performance for the test case from https://github.com/tc39/proposal-bigint/issues/117. (Make sure to use JSGC_DISABLE_POISONING=1 to avoid measuring GC poisoning cost.)

This bug is also a prerequisite for optimising BigInt on int64 values without actually allocating BigInt objects. When most BigInt allocations can be optimised away, the "sha512-with-bigints.js" test case even runs slightly faster than "sha512-with-runtime-long.js" for us. But we also regressed "sha512-with-runtime-long.js" with Warp (by ~50% when compared to Ion, IIRC), so that should probably be taken into account, too.

Comment 1

[André Bargull [:anba]]

Attachment: Bug 1685708 - Part 1: Handle no-op cases for 64-bit results in Big.as{Uint,Int}N. r=jandem!

The fast path didn't handle the no-op case, which actually made the fast-path
slower for the case when no conversion is necessary.

Comment 2

[André Bargull [:anba]]

Attachment: Bug 1685708 - Part 2: Add CacheIR support for Big.as{Uint,Int}N. r=jandem!

Add CacheIR support for Big.as{Uint,Int}N() so we can optimise these functions
more efficiently in Warp in part 5.

Depends on D101167

Comment 3

[André Bargull [:anba]]

Attachment: Bug 1685708 - Part 3: Support Signed/NotSigned in MacroAssembler::branchTest64 on 32-bit platforms. r=jandem!

Support Signed/NotSigned in preparation for part 5.

Depends on D101168

Comment 4

[André Bargull [:anba]]

Attachment: Bug 1685708 - Part 4: Remove register restrictions from MacroAssembler::move{8,16,32}To64SignExtend. r=jandem!

For the next part we want to call these methods without having to worry about
the edx:eax restriction on x86.

Depends on D101169

Comment 5

[André Bargull [:anba]]

Attachment: Bug 1685708 - Part 5: Transpile BigInt.as{Int,Uint}N. r=jandem!

BigInt.as{Int,Uint}N(bits, x) with bits={32,64} are expected to be common enough
to warrant providing specialised code. For example BigInt.asIntN(64, x + y) can
be used to inform the compiler to perform Int64 additions.

Depends on D101170

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/de98a7e28f06
Part 1: Handle no-op cases for 64-bit results in Big.as{Uint,Int}N. r=jandem
https://hg.mozilla.org/integration/autoland/rev/c7a807bd4deb
Part 2: Add CacheIR support for Big.as{Uint,Int}N. r=jandem
https://hg.mozilla.org/integration/autoland/rev/db013483866a
Part 3: Support Signed/NotSigned in MacroAssembler::branchTest64 on 32-bit platforms. r=jandem
https://hg.mozilla.org/integration/autoland/rev/1273409d014c
Part 4: Remove register restrictions from MacroAssembler::move{8,16,32}To64SignExtend. r=jandem
https://hg.mozilla.org/integration/autoland/rev/ff678e63e677
Part 5: Transpile BigInt.as{Int,Uint}N. r=jandem

Comment 7

[Razvan Maries]

Backed out for build bustages.

Push with failures: https://treeherder.mozilla.org/jobs?repo=autoland&searchStr=Linux%2Cx64%2Cdebug%2CSpidermonkey%2Cbuilds%2Cspidermonkey-sm-nonunified-linux64%2Fdebug%2Cnu&revision=ff678e63e67725839bb11c3bfd25ec4a4d15ed51&selectedTaskRun=fD2ETEbhS_CiF6fp8z_vSA.0

Log: https://treeherder.mozilla.org/logviewer?job_id=326591926&repo=autoland&lineNumber=2600

Backout: https://hg.mozilla.org/integration/autoland/rev/c12bbd1b6404576ad6a74ad01a67e9245df38d88

Comment 8

[André Bargull [:anba]]

Missing #include leading to non-unified builds bustage. I'll update the patch shortly. Thanks for the info!

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/18f3ee438da2
Part 1: Handle no-op cases for 64-bit results in Big.as{Uint,Int}N. r=jandem
https://hg.mozilla.org/integration/autoland/rev/501a75fb9ffb
Part 2: Add CacheIR support for Big.as{Uint,Int}N. r=jandem
https://hg.mozilla.org/integration/autoland/rev/d6617eb8f783
Part 3: Support Signed/NotSigned in MacroAssembler::branchTest64 on 32-bit platforms. r=jandem
https://hg.mozilla.org/integration/autoland/rev/095a87205614
Part 4: Remove register restrictions from MacroAssembler::move{8,16,32}To64SignExtend. r=jandem
https://hg.mozilla.org/integration/autoland/rev/4711d0893629
Part 5: Transpile BigInt.as{Int,Uint}N. r=jandem

Comment 10

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/18f3ee438da2
https://hg.mozilla.org/mozilla-central/rev/501a75fb9ffb
https://hg.mozilla.org/mozilla-central/rev/d6617eb8f783
https://hg.mozilla.org/mozilla-central/rev/095a87205614
https://hg.mozilla.org/mozilla-central/rev/4711d0893629

Comment 11

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/18f3ee438da2
https://hg.mozilla.org/mozilla-central/rev/501a75fb9ffb
https://hg.mozilla.org/mozilla-central/rev/d6617eb8f783
https://hg.mozilla.org/mozilla-central/rev/095a87205614
https://hg.mozilla.org/mozilla-central/rev/4711d0893629