# RUN: llc -mtriple=thumbv8.1m.main %s -run-pass=arm-low-overhead-loops --verify-machineinstrs -o - | FileCheck %s

# CHECK: while.body:
# CHECK-NOT: t2DLS
# CHECK-NOT: t2LEUpdate

--- |
  target datalayout = "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64"
  target triple = "thumbv8.1m.main"
  
  define i32 @skip_spill(i32 %n) #0 {
  entry:
    %cmp6 = icmp eq i32 %n, 0
    br i1 %cmp6, label %while.end, label %while.body.preheader
  
  while.body.preheader:                             ; preds = %entry
    %start = call i32 @llvm.start.loop.iterations.i32(i32 %n)
    br label %while.body
  
  while.body:                                       ; preds = %while.body, %while.body.preheader
    %res.07 = phi i32 [ %add, %while.body ], [ 0, %while.body.preheader ]
    %0 = phi i32 [ %start, %while.body.preheader ], [ %1, %while.body ]
    %call = tail call i32 bitcast (i32 (...)* @bar to i32 ()*)()
    %add = add nsw i32 %call, %res.07
    %1 = call i32 @llvm.loop.decrement.reg.i32.i32.i32(i32 %0, i32 1)
    %2 = icmp ne i32 %1, 0
    br i1 %2, label %while.body, label %while.end
  
  while.end:                                        ; preds = %while.body, %entry
    %res.0.lcssa = phi i32 [ 0, %entry ], [ %add, %while.body ]
    ret i32 %res.0.lcssa
  }
  
  declare i32 @bar(...) local_unnamed_addr #0
  
  declare i32 @llvm.start.loop.iterations.i32(i32) #1
  declare i32 @llvm.loop.decrement.reg.i32.i32.i32(i32, i32) #1
  
  attributes #0 = { "target-features"="+mve.fp" }
  attributes #1 = { noduplicate nounwind }
  attributes #2 = { nounwind }

...
---
name:            skip_spill
alignment:       2
exposesReturnsTwice: false
legalized:       false
regBankSelected: false
selected:        false
failedISel:      false
tracksRegLiveness: true
hasWinCFI:       false
registers:       []
liveins:
  - { reg: '$r0', virtual-reg: '' }
frameInfo:
  isFrameAddressTaken: false
  isReturnAddressTaken: false
  hasStackMap:     false
  hasPatchPoint:   false
  stackSize:       16
  offsetAdjustment: 0
  maxAlignment:    4
  adjustsStack:    true
  hasCalls:        true
  stackProtector:  ''
  maxCallFrameSize: 0
  cvBytesOfCalleeSavedRegisters: 0
  hasOpaqueSPAdjustment: false
  hasVAStart:      false
  hasMustTailInVarArgFunc: false
  localFrameSize:  0
  savePoint:       ''
  restorePoint:    ''
fixedStack:      []
stack:
  - { id: 0, name: '', type: spill-slot, offset: -4, size: 4, alignment: 4, 
      stack-id: default, callee-saved-register: '$lr', callee-saved-restored: false, 
      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
  - { id: 1, name: '', type: spill-slot, offset: -8, size: 4, alignment: 4, 
      stack-id: default, callee-saved-register: '$r7', callee-saved-restored: true, 
      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
  - { id: 2, name: '', type: spill-slot, offset: -12, size: 4, alignment: 4, 
      stack-id: default, callee-saved-register: '$r5', callee-saved-restored: true, 
      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
  - { id: 3, name: '', type: spill-slot, offset: -16, size: 4, alignment: 4, 
      stack-id: default, callee-saved-register: '$r4', callee-saved-restored: true, 
      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
callSites:       []
constants:       []
machineFunctionInfo: {}
body:             |
  bb.0.entry:
    successors: %bb.4(0x30000000), %bb.1(0x50000000)
    liveins: $r0, $r4, $r5, $r7, $lr
  
    frame-setup tPUSH 14, $noreg, killed $r4, killed $r5, killed $r7, killed $lr, implicit-def $sp, implicit $sp
    frame-setup CFI_INSTRUCTION def_cfa_offset 16
    frame-setup CFI_INSTRUCTION offset $lr, -4
    frame-setup CFI_INSTRUCTION offset $r7, -8
    frame-setup CFI_INSTRUCTION offset $r5, -12
    frame-setup CFI_INSTRUCTION offset $r4, -16
    tCBZ $r0, %bb.4
  
  bb.1.while.body.preheader:
    successors: %bb.2(0x80000000)
    liveins: $r0
  
    $lr = tMOVr $r0, 14, $noreg
    renamable $r4, dead $cpsr = tMOVi8 0, 14, $noreg
    $lr = t2DoLoopStart killed $r0
  
  bb.2.while.body:
    successors: %bb.2(0x7c000000), %bb.3(0x04000000)
    liveins: $lr, $r4
  
    $r5 = tMOVr killed $lr, 14, $noreg
    tBL 14, $noreg, @bar, csr_aapcs, implicit-def dead $lr, implicit $sp, implicit-def $sp, implicit-def $r0
    $lr = tMOVr killed $r5, 14, $noreg
    renamable $r4 = nsw tADDhirr killed renamable $r4, killed renamable $r0, 14, $noreg
    renamable $lr = t2LoopDec killed renamable $lr, 1
    t2LoopEnd renamable $lr, %bb.2, implicit-def dead $cpsr
    tB %bb.3, 14, $noreg
  
  bb.3.while.end:
    liveins: $r4
  
    $r0 = tMOVr killed $r4, 14, $noreg
    tPOP_RET 14, $noreg, def $r4, def $r5, def $r7, def $pc, implicit killed $r0
  
  bb.4:
    renamable $r4, dead $cpsr = tMOVi8 0, 14, $noreg
    $r0 = tMOVr killed $r4, 14, $noreg
    tPOP_RET 14, $noreg, def $r4, def $r5, def $r7, def $pc, implicit killed $r0

...