cmd/internal/obj/arm64: remove the transition from $0 to ZR
Previously we convert $0 to the ZR register for some reasons, which causes
two problems:
1. Confusion, the special case of the ZR register needs to be considered
when dealing with constants. For encoding, some places we encode ZR, and
some places we encode $0, although we have converted $0 to ZR.
2. Unexpected instruction format. All instructions that support ZR register
operands can be replaced by $0.
This patch removes this conversion. Note that this patch may cause previously
unintendedly supported instruction formats to no longer be supported.
Change-Id: I3d8d2c06711b7614a38191397da7776417f1861c
Reviewed-on: https://go-review.googlesource.com/c/go/+/404316 Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Eric Fang <eric.fang@arm.com> Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>