Create a new channel as a copy of main.
Rename main to:
Delete main? This cannot be undone.
// RUN: llvm-mc -triple aarch64 -show-encoding -mattr=+v8r -o - %s | FileCheck %s .text dfb // CHECK: .text // CHECK-NEXT: dfb // encoding: [0x9f,0x3c,0x03,0xd5]