llvm/test/CodeGen/ARM/virtregrewriter-subregliveness.mir

# RUN: llc  -o -  -mtriple=thumbv7--windows-gnu -run-pass=greedy -run-pass=virtregrewriter %s | FileCheck %s
--- |
  target datalayout = "e-m:w-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
  target triple = "thumbv7--windows-gnu"
  
  define void @subregLiveThrough() { ret void }
  define void @subregNotLiveThrough() { ret void }
  define void @subregNotLiveThrough2() { ret void }

...
---
# Check that we properly recognize that r1 is live through
# the first subreg copy.
# That will materialize as an implicit use of the big register
# on that copy.
# PR34107.
#
# CHECK-LABEL: name: subregLiveThrough
name:            subregLiveThrough
tracksRegLiveness: true
registers:
  - { id: 0, class: gprpair }
body:             |
  bb.0:
    liveins: $r0, $r1

    ; That copy is being coalesced so we should use a KILL
    ; placeholder. If that's not a kill that means we probably
    ; not coalescing %0 and $r0_r1 and thus we are not testing
    ; the problematic code anymore.
    ;
    ; CHECK: $r0 = KILL $r0, implicit killed $r0_r1, implicit-def $r0_r1
    ; CHECK-NEXT: $r1 = KILL $r1, implicit killed $r0_r1
    undef %0.gsub_0 = COPY $r0
    %0.gsub_1 = COPY $r1
    tBX_RET 14, $noreg, implicit %0
  

...

---
# Check that we properly recognize that r1 is *not* live through
# the first subreg copy.
# CHECK-LABEL: name: subregNotLiveThrough
name:            subregNotLiveThrough
tracksRegLiveness: true
registers:
  - { id: 0, class: gprpair }
body:             |
  bb.0:
    liveins: $r0, $r1

    ; r1 is not live through so check we are not implicitly using
    ; the big register.
    ; CHECK: $r0 = KILL $r0, implicit-def $r0_r1
    ; CHECK-NEXT: tBX_RET
    undef %0.gsub_0 = COPY $r0
    tBX_RET 14, $noreg, implicit %0
  

...

---
# Check that we properly recognize that r1 is *not* live through
# the first subreg copy. It is defined by this copy, but is not
# through.
# CHECK-LABEL: name: subregNotLiveThrough2
name:            subregNotLiveThrough2
tracksRegLiveness: true
registers:
  - { id: 0, class: gprpair }
body:             |
  bb.0:
    liveins: $r0, $r1

    ; r1 is not live through so check we are not implicitly using
    ; the big register.
    ; CHECK: $r0 = KILL $r0, implicit-def $r1, implicit-def $r0_r1
    ; CHECK-NEXT: tBX_RET
    undef %0.gsub_0 = COPY $r0, implicit-def $r1
    tBX_RET 14, $noreg, implicit %0
  

...