Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: a3e4439fb95cefbdcebb8d1fd4739a1db1d6d267
https://github.com/WebKit/WebKit/commit/a3e4439fb95cefbdcebb8d1fd4739a1db1d6d267
Author: Sosuke Suzuki <[email protected]>
Date: 2026-04-14 (Tue, 14 Apr 2026)
Changed paths:
A JSTests/microbenchmarks/array-length-reset-double.js
A JSTests/stress/array-length-store-ic-double-noncow.js
A JSTests/stress/array-length-store-ic-double-then-int32.js
M Source/JavaScriptCore/bytecode/InlineCacheCompiler.cpp
Log Message:
-----------
[JSC] Support `DoubleShape` in `ArrayLengthStore` IC
https://bugs.webkit.org/show_bug.cgi?id=312050
Reviewed by Yusuke Suzuki.
311326@main added an ArrayLengthStore inline cache that handles
ArrayWithInt32 and ArrayWithContiguous. This patch extends it to
ArrayWithDouble by selecting the hole pattern (encoded empty JSValue
vs PNaN) at the shape guard, the same way FTL initializeArrayElements
does, and using a single store64 clear loop. The Int32/Contiguous
fast path gains only a single `movz #0`.
FTL:
TipOfTree Patched
array-length-reset-double 63.4825+-4.1166 ^ 13.0505+-0.4404
^ definitely 4.8644x faster
DFG:
TipOfTree Patched
array-length-reset-double 61.7985+-0.9654 ^ 15.8700+-0.5495
^ definitely 3.8940x faster
Baseline:
TipOfTree Patched
array-length-reset-double 121.8742+-2.5465 ^ 75.3147+-0.3700
^ definitely 1.6182x faster
Tests: JSTests/microbenchmarks/array-length-reset-double.js
JSTests/stress/array-length-store-ic-double-noncow.js
JSTests/stress/array-length-store-ic-double-then-int32.js
* JSTests/microbenchmarks/array-length-reset-double.js: Added.
(test):
* JSTests/stress/array-length-store-ic-double-noncow.js: Added.
(shouldBe):
(f):
* JSTests/stress/array-length-store-ic-double-then-int32.js: Added.
(shouldBe):
(f):
* Source/JavaScriptCore/bytecode/InlineCacheCompiler.cpp:
(JSC::InlineCacheCompiler::generateWithGuard):
Canonical link: https://commits.webkit.org/311181@main
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