1763163 - Reduce register usage in LIsNullOrLikeUndefinedV, LNotV, and LIsNullOrLikeUndefinedV

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, enhancement, P1)

Description

[André Bargull [:anba]]

We can save 1-2 temp registers in these LIR nodes.

IIRC I saw some extra moves in µ-benchmarks which were caused by these unnecessary temp registers.

Comment 1

[André Bargull [:anba]]

Attachment: Bug 1763163 - Part 1: Use no temp registers for strict equality against null or undefined. r=iain!

Split the strict equality case from LIsNullOrLikeUndefined(AndBranch)V, which
saves two registers on 64-bit systems.

Comment 2

[André Bargull [:anba]]

Attachment: Bug 1763163 - Part 2: Use registers instead of definitions for testValueTruthy. r=iain!

For the next patches, testValueTruthy needs to work on Register instead of
LDefinition*.

Depends on D142954

Comment 3

[André Bargull [:anba]]

Attachment: Bug 1763163 - Part 3: Reduce temp registers for LNotV. r=iain!

We can use the output register as a temp register for testValueTruthy().

Depends on D142955

Comment 4

[André Bargull [:anba]]

Attachment: Bug 1763163 - Part 4: Update a comment about TI. r=iain!

TI is gone.

Depends on D142956

Comment 5

[André Bargull [:anba]]

Attachment: Bug 1763163 - Part 5: Reduce temp registers for LIsNullOrLikeUndefinedV. r=iain!

We can use the output register as an additional temp register for
branchTestObjectEmulatesUndefined().

Depends on D142957

Comment 6

[André Bargull [:anba]]

Attachment: Bug 1763163 - Part 6: Use temp-unbox registers for LNotV and LTestVAndBranch. r=iain!

That way it matches the temp-unbox register use in LIsNullOrLikeUndefined(AndBranch)V.

Depends on D142958

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/1696bfed1cc1
Part 1: Use no temp registers for strict equality against null or undefined. r=iain
https://hg.mozilla.org/integration/autoland/rev/6b1882146ddb
Part 2: Use registers instead of definitions for testValueTruthy. r=iain
https://hg.mozilla.org/integration/autoland/rev/a2cc738fe932
Part 3: Reduce temp registers for LNotV. r=iain
https://hg.mozilla.org/integration/autoland/rev/5f9460d2258f
Part 4: Update a comment about TI. r=iain
https://hg.mozilla.org/integration/autoland/rev/a5a909a61e2b
Part 5: Reduce temp registers for LIsNullOrLikeUndefinedV. r=iain
https://hg.mozilla.org/integration/autoland/rev/fc1c4e52f54f
Part 6: Use temp-unbox registers for LNotV and LTestVAndBranch. r=iain

Comment 8

[Cristina Cozmuta (:CrissCozmuta)]

https://hg.mozilla.org/mozilla-central/rev/1696bfed1cc1
https://hg.mozilla.org/mozilla-central/rev/6b1882146ddb
https://hg.mozilla.org/mozilla-central/rev/a2cc738fe932
https://hg.mozilla.org/mozilla-central/rev/5f9460d2258f
https://hg.mozilla.org/mozilla-central/rev/a5a909a61e2b
https://hg.mozilla.org/mozilla-central/rev/fc1c4e52f54f