cmd/internal/obj/arm64: add checks for incorrect use of REGTMP register
The current assembler uses REGTMP as a temporary destination register,
when optimizing one instruction into a multi-instruction sequence. But
in some cases, when the source register is REGTMP, this behavior is
incorrect.
For example:
ADD $0x1234567, R27, R3
The current assembler encodes it into
MOVD $17767, R27
MOVK $(291<<16), R27
ADD R27, R27, R3
It is illegal to overwrite R27. This CL adds the related checks.
Add test cases.
Change-Id: I0af373d9fd23d8f067c093778dd4cc76748faf38
Reviewed-on: https://go-review.googlesource.com/c/go/+/344689 Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: fannie zhang <Fannie.Zhang@arm.com>