abf1d96d17
On X64 you can use `movb` instruction with any register, so there is no need to require a fixed register. This improves the quality of register allocation decisions around such stores. Issue https://github.com/dart-lang/sdk/issues/56705 TEST=ci Change-Id: Id4d977853fec4a7900cb33c3062257735505ab8b Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/384703 Reviewed-by: Daco Harkes <dacoharkes@google.com> Commit-Queue: Daco Harkes <dacoharkes@google.com> Auto-Submit: Slava Egorov <vegorov@google.com>