[webkit-changes] [WebKit/WebKit] c4e675: B3 Select instruction truncates vector operands

[Commit Queue]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: c4e675b3afdd1aa16c3d3d3bd38c503bece0df0f
      https://github.com/WebKit/WebKit/commit/c4e675b3afdd1aa16c3d3d3bd38c503bece0df0f
  Author: David Degazio <d_degazio at apple.com>
  Date:   2023-06-08 (Thu, 08 Jun 2023)

  Changed paths:
    A JSTests/wasm/stress/simd-select.js
    M Source/JavaScriptCore/b3/B3LowerToAir.cpp

  Log Message:
  -----------
  B3 Select instruction truncates vector operands
https://bugs.webkit.org/show_bug.cgi?id=257842
rdar://108643371

Reviewed by Mark Lam, Justin Michaud and Yusuke Suzuki.

Fixes a bug where we would generate a double-precision conditional
move when lowering the Select B3 instruction on vector operands.
Since vector-sized conditional move isn't widely supported, we
transform the Select into a branch and moves during Air lowering
when the operands are vectors.

* JSTests/wasm/stress/simd-select.js: Added.
* Source/JavaScriptCore/b3/B3LowerToAir.cpp:

Canonical link: https://commits.webkit.org/264996@main