Create a new channel as a copy of main.
Rename main to:
Delete main? This cannot be undone.
@ RUN: not llvm-mc -triple=armv8 < %s 2>&1 | FileCheck %s swp r0, r1, [r2] @ CHECK: instruction requires: armv7 or earlier swpb r0, r1, [r2] @ CHECK: instruction requires: armv7 or earlier