llvm/llvm/test/CodeGen/AArch64/wineh-save-lrpair1.mir

# RUN: llc -o - %s -mtriple=aarch64-windows -start-before=prologepilog \
# RUN:   -stop-after=prologepilog | FileCheck %s
# RUN: llc -o - %s -mtriple=aarch64-windows -start-before=prologepilog \
# RUN:   | FileCheck --check-prefix=ASM %s

# Check that an odd callee-saved GPR is paired with lr

# CHECK: early-clobber $sp = frame-setup STPXpre killed $x19, killed $x20, $sp, -4
# CHECK-NEXT: frame-setup SEH_SaveRegP_X 19, 20, -32
# CHECK-NEXT: frame-setup STPXi killed $x21, killed $lr, $sp, 2
# CHECK-NEXT: frame-setup SEH_SaveRegP 21, 30, 16
# CHECK-NEXT: frame-setup SEH_PrologEnd

# ASM:      stp x19, x20, [sp, #-32]!
# ASM-NEXT: .seh_save_regp_x x19, 32
# ASM-NEXT: stp x21, x30, [sp, #16]
# ASM-NEXT: .seh_save_lrpair x21, 16
# ASM-NEXT: .seh_endprologue

--- |

  define dso_local i32 @func(i32 %a) { ret i32 %a }
  declare dso_local i32 @other()

...
---
name:            func
alignment:       4
exposesReturnsTwice: false
legalized:       false
regBankSelected: false
selected:        false
failedISel:      false
tracksRegLiveness: true
hasWinCFI:       false
registers:       []
liveins:         []
frameInfo:
  isFrameAddressTaken: false
  isReturnAddressTaken: false
  hasStackMap:     false
  hasPatchPoint:   false
  stackSize:       0
  offsetAdjustment: 0
  maxAlignment:    4
  adjustsStack:    false
  hasCalls:        false
  stackProtector:  ''
  maxCallFrameSize: 0
  cvBytesOfCalleeSavedRegisters: 0
  hasOpaqueSPAdjustment: false
  hasVAStart:      false
  hasMustTailInVarArgFunc: false
  localFrameSize:  4
  savePoint:       ''
  restorePoint:    ''
fixedStack:      []
stack:           []
callSites:       []
constants:       []
machineFunctionInfo: {}
body:             |
  bb.0:
    liveins: $x0, $x21, $x19, $x20

    BL @other, csr_aarch64_aapcs, implicit-def dead $lr, implicit $sp, implicit $w0, implicit-def $sp, implicit-def $w0
    $x19 = ADDXrr $x0, $x0
    $x20 = ADDXrr $x19, $x0
    $x21 = ADDXrr $x20, killed $x19
    $x0 = ADDXrr $x0, killed $x21

    RET_ReallyLR

...