Fork channel

Create a new channel as a copy of main.

Rename channel

Rename main to:

Delete channel

Delete main? This cannot be undone.

decode-err.txt
# RUN: llvm-mc -arch=amdgcn -mcpu=gfx900 -disassemble -show-encoding < %s 2>&1 | FileCheck -check-prefix=GCN %s
# RUN: llvm-mc -arch=amdgcn -mcpu=gfx1100 -disassemble -show-encoding < %s 2>&1 | FileCheck -check-prefix=GFX11 %s

# GCN: warning: invalid instruction encoding
0xdf,0x00,0x00,0x02

# this is buffer_atomic_csub_u32 v5, off, s[8:11], s3 offset:4095. Invalid without glc
# GFX11: warning: invalid instruction encoding
0xff,0x0f,0xdc,0xe0,0x00,0x05,0x02,0x03