llvm/test/CodeGen/AArch64/reverse-csr-restore-seq.mir

# RUN: llc -run-pass=prologepilog -reverse-csr-restore-seq -o - -mtriple=aarch64-- %s | FileCheck %s --check-prefixes=CHECK
# RUN: llc -start-before=prologepilog -stop-after=aarch64-ldst-opt -reverse-csr-restore-seq -o - -mtriple=aarch64-- %s | FileCheck %s --check-prefixes=CHECK
#
--- |

  define void @foo() nounwind { entry: unreachable }

  define void @bar() nounwind { entry: unreachable }

  define void @baz() nounwind { entry: unreachable }

...
---
name:            foo
# CHECK-LABEL: name: foo
tracksRegLiveness: true
body:             |
  bb.0:
    $x19 = IMPLICIT_DEF
    $x20 = IMPLICIT_DEF
    $x21 = IMPLICIT_DEF
    $x22 = IMPLICIT_DEF
    $x23 = IMPLICIT_DEF
    $x24 = IMPLICIT_DEF
    $x25 = IMPLICIT_DEF
    $x26 = IMPLICIT_DEF

  ; The local stack size is 0, so the last ldp in the sequence will also
  ; restore the stack.
  ; CHECK: $x24, $x23 = frame-destroy LDPXi $sp, 2
  ; CHECK-NEXT: $x22, $x21 = frame-destroy LDPXi $sp, 4
  ; CHECK-NEXT: $x20, $x19 = frame-destroy LDPXi $sp, 6

  ; The ldp and the stack increment get merged even before
  ; the load-store optimizer.
  ; CHECK-NEXT: early-clobber $sp, $x26, $x25 = frame-destroy LDPXpost $sp, 8

    RET_ReallyLR
...
---
name:            bar
# CHECK-LABEL: name: bar
tracksRegLiveness: true
stack:
  - { id : 0, size: 8, alignment: 4,
  stack-id: default, callee-saved-register: '', callee-saved-restored: true,
  local-offset: -4, debug-info-variable: '', debug-info-expression: '',
  debug-info-location: '' }

body:             |
  bb.0:
    $x19 = IMPLICIT_DEF
    $x20 = IMPLICIT_DEF
    $x21 = IMPLICIT_DEF
    $x22 = IMPLICIT_DEF
    $x23 = IMPLICIT_DEF
    $x24 = IMPLICIT_DEF
    $x25 = IMPLICIT_DEF
    $x26 = IMPLICIT_DEF

  ; The local stack size is not 0, and we can combine the CSR stack size with
  ; the local stack size. This results in rewriting the offsets for all the
  ; save/restores and forbids us to merge the stack adjustment and the last pop.
  ; In this case, there is no point of moving the first CSR pair at the end.
  ; We do it anyway, as it's a small price to pay for the resulting
  ; simplification in the epilogue emission code.
  ; CHECK:      $x24, $x23 = frame-destroy LDPXi $sp, 4
  ; CHECK-NEXT: $x22, $x21 = frame-destroy LDPXi $sp, 6
  ; CHECK-NEXT: $x20, $x19 = frame-destroy LDPXi $sp, 8
  ; CHECK-NEXT: $x26, $x25 = frame-destroy LDPXi $sp, 2
  ; CHECK-NEXT: $sp = frame-destroy ADDXri $sp, 80, 0
    RET_ReallyLR
...
---
# Check that the load from the offset 0 is moved at the end even when hasFP is
# false.
name:            baz
# CHECK-LABEL: name: baz
alignment:       4
tracksRegLiveness: true
frameInfo:
  adjustsStack:    true
  hasCalls:        true
body:             |
  bb.0:
    successors: %bb.1

    $x0 = IMPLICIT_DEF
    $x20 = IMPLICIT_DEF
    $x21 = IMPLICIT_DEF

    ADJCALLSTACKDOWN 0, 0, implicit-def dead $sp, implicit $sp
    BL @foo, csr_aarch64_aapcs, implicit-def dead $lr, implicit $sp, implicit $x0, implicit-def $sp, implicit-def $x0
    ADJCALLSTACKUP 0, 0, implicit-def dead $sp, implicit $sp
    B %bb.1

  bb.1:
   ; CHECK: $x21, $x20 = frame-destroy LDPXi $sp, 2
   ; CHECK-NEXT: early-clobber $sp, $lr = frame-destroy LDRXpost $sp, 32
    RET_ReallyLR
...