[webkit-changes] [WebKit/WebKit] dda4fc: [JSC] Make Move32 elimination more optimistic

[Yusuke Suzuki]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: dda4fc219fa7543f30a49a1ea394188114f94017
      https://github.com/WebKit/WebKit/commit/dda4fc219fa7543f30a49a1ea394188114f94017
  Author: Yusuke Suzuki <ysuzuki at apple.com>
  Date:   2022-12-10 (Sat, 10 Dec 2022)

  Changed paths:
    M Source/JavaScriptCore/b3/air/AirAllocateRegistersByGraphColoring.cpp

  Log Message:
  -----------
  [JSC] Make Move32 elimination more optimistic
https://bugs.webkit.org/show_bug.cgi?id=249086
rdar://103218582

Reviewed by Justin Michaud.

We are not removing Move32 if arg0's def is more than 32bit or arg1's use is more than 32bit.
But we do not need to make it super conservative. This patch relaxes this condition so that
we avoid optimization only when the arg0's def is more than 32bit. So, we can allow removing
Move32 where source-def is 32bit and destination-use is 64bit.
This improves JetStream2 by 0.45% with 98% confidence.

* Source/JavaScriptCore/b3/air/AirAllocateRegistersByGraphColoring.cpp:

Canonical link: https://commits.webkit.org/257694@main