This makes it so we never find a reg_decl in between a reg_store and the def for its value, which helps avid inserting copy movs. Reviewed-by: Faith Ekstrand <faith.ekstrand@collabora.com> Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24153>