llvm/test/CodeGen/AMDGPU/subreg_interference.mir

# RUN: llc -o - %s -mtriple=amdgcn--amdhsa -verify-machineinstrs -run-pass=greedy,virtregrewriter | FileCheck %s
--- |

  define amdgpu_kernel void @func0() {
    ret void
  }

...

---
# We should not detect any interference between v0/v1 here and only allocate
# sgpr0-sgpr3.
#
# CHECK-LABEL: func0
# CHECK: S_NOP 0, implicit-def renamable $sgpr0
# CHECK: S_NOP 0, implicit-def renamable $sgpr3
# CHECK: S_NOP 0, implicit-def renamable $sgpr1
# CHECK: S_NOP 0, implicit-def renamable $sgpr2
# CHECK: S_NOP 0, implicit renamable $sgpr0, implicit renamable $sgpr3
# CHECK: S_NOP 0, implicit renamable $sgpr1, implicit renamable $sgpr2
name: func0
body: |
  bb.0:
    S_NOP 0, implicit-def undef %0.sub0 : sgpr_128
    S_NOP 0, implicit-def %0.sub3
    S_NOP 0, implicit-def undef %1.sub1 : sgpr_128
    S_NOP 0, implicit-def %1.sub2


    S_NOP 0, implicit %0.sub0, implicit %0.sub3
    S_NOP 0, implicit %1.sub1, implicit %1.sub2
...