[webkit-changes] [WebKit/WebKit] b6c35f: [JSC] Still optimize String.at, .charAt, .charCode...

[David Degazio]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: b6c35f4cd18125c7d3acb54ace62b9d74a67a45c
      https://github.com/WebKit/WebKit/commit/b6c35f4cd18125c7d3acb54ace62b9d74a67a45c
  Author: David Degazio <d_degazio at apple.com>
  Date:   2025-02-27 (Thu, 27 Feb 2025)

  Changed paths:
    M Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp

  Log Message:
  -----------
  [JSC] Still optimize String.at, .charAt, .charCodeAt, and .codePointAt in DFG when called with no arguments
https://bugs.webkit.org/show_bug.cgi?id=288657
rdar://145696925

Reviewed by Yijia Huang.

Parses calls to String.at, .charAt, .charCodeAt, and .codePointAt with no arguments
(not including this) into their respective intrinsics but with a constant zero index,
since coercing an undefined argument into an integer as is done in these intrinsics
always returns zero. Previously, we wouldn't optimize such calls, potentially limiting
DFG/FTL performance on this weird but apparently not too uncommon pattern.

* Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp:
(JSC::DFG::ByteCodeParser::handleIntrinsicCall):

Canonical link: https://commits.webkit.org/291263@main



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