[webkit-changes] [WebKit/WebKit] 444126: [JSC] Fix staturated conversion and compare64

[Yusuke Suzuki]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 444126aaa8125965e1e8315c57f1778fed8af390
      https://github.com/WebKit/WebKit/commit/444126aaa8125965e1e8315c57f1778fed8af390
  Author: Yusuke Suzuki <ysuzuki at apple.com>
  Date:   2023-02-20 (Mon, 20 Feb 2023)

  Changed paths:
    M Source/JavaScriptCore/wasm/WasmBBQJIT.cpp

  Log Message:
  -----------
  [JSC] Fix staturated conversion and compare64
https://bugs.webkit.org/show_bug.cgi?id=252623
rdar://105699589

Reviewed by Michael Saboff.

1. We should not allocate new scratch registers inside truncInBounds for x64 since they can be the same to resultLocation / operationLocation's FPRs.
   And in that case, this does not work. Let's just pass already allocated FPRs.
2. We fix emitCompareI64. After `ImmHelpers::immLocation(lhsLocation, rhsLocation) = Location::fromGPR(m_scratchGPR);`, `ImmHelpers::immLocation(lhsLocation, rhsLocation)` can always return lhsLocation,
   since both locations are no longer imm.

* Source/JavaScriptCore/wasm/WasmBBQJIT.cpp:
(JSC::Wasm::BBQJIT::truncInBounds):
(JSC::Wasm::BBQJIT::truncTrapping):
(JSC::Wasm::BBQJIT::truncSaturated):
(JSC::Wasm::BBQJIT::emitCompareI64):

Canonical link: https://commits.webkit.org/260581@main