test/CodeGen/AArch64/spill-undef.mir

# RUN: llc %s -run-pass greedy -o - | FileCheck %s
# Check that we don't insert spill code for undef values.
# Uninitialized memory for them is fine.
# PR33311
--- |
  ; ModuleID = 'stuff.ll'
  target triple = "aarch64--"
  
  @g = external global i32
  
  define void @foobar() {
    ret void
  }
  
...
---
name:            foobar
alignment:       2
tracksRegLiveness: true
registers:       
  - { id: 0, class: gpr32 }
  - { id: 1, class: gpr32 }
  - { id: 2, class: gpr32all }
  - { id: 3, class: gpr32 }
  - { id: 4, class: gpr64common }
  - { id: 5, class: gpr32 }
  - { id: 6, class: gpr64common }
  - { id: 7, class: gpr32 }
  - { id: 8, class: gpr32 }
  - { id: 9, class: gpr64 }
body:             |
  bb.0:
    liveins: %x0
    successors: %bb.1, %bb.2

    ; %8 is going to be spilled.
    ; But on that path, we don't care about its value.
    ; Emit a simple KILL instruction instead of an
    ; actual spill.
    ; CHECK: [[UNDEF:%[0-9]+]] = IMPLICIT_DEF
    ; CHECK-NEXT: KILL [[UNDEF]]
    %8 = IMPLICIT_DEF
    ; %9 us going to be spilled.
    ; But it is only partially undef.
    ; Make sure we spill it properly
    ; CHECK: [[NINE:%[0-9]+]] = COPY %x0
    ; CHECK: [[NINE]].sub_32 = IMPLICIT_DEF
    ; CHECK-NEXT: STRXui [[NINE]]
    %9 = COPY %x0
    %9.sub_32 = IMPLICIT_DEF
    CBNZW %wzr, %bb.2
    B %bb.1
  
  bb.1:
    %4 = ADRP target-flags(aarch64-page) @g
    %8 = LDRWui %4, target-flags(aarch64-pageoff, aarch64-nc) @g :: (volatile dereferenceable load 4 from @g)
    INLINEASM $nop, 1, 12, implicit-def dead early-clobber %x0, 12, implicit-def dead early-clobber %x1, 12, implicit-def dead early-clobber %x2, 12, implicit-def dead early-clobber %x3, 12, implicit-def dead early-clobber %x4, 12, implicit-def dead early-clobber %x5, 12, implicit-def dead early-clobber %x6, 12, implicit-def dead early-clobber %x7, 12, implicit-def dead early-clobber %x8, 12, implicit-def dead early-clobber %x9, 12, implicit-def dead early-clobber %x10, 12, implicit-def dead early-clobber %x11, 12, implicit-def dead early-clobber %x12, 12, implicit-def dead early-clobber %x13, 12, implicit-def dead early-clobber %x14, 12, implicit-def dead early-clobber %x15, 12, implicit-def dead early-clobber %x16, 12, implicit-def dead early-clobber %x17, 12, implicit-def dead early-clobber %x18, 12, implicit-def dead early-clobber %x19, 12, implicit-def dead early-clobber %x20, 12, implicit-def dead early-clobber %x21, 12, implicit-def dead early-clobber %x22, 12, implicit-def dead early-clobber %x23, 12, implicit-def dead early-clobber %x24, 12, implicit-def dead early-clobber %x25, 12, implicit-def dead early-clobber %x26, 12, implicit-def dead early-clobber %x27, 12, implicit-def dead early-clobber %x28, 12, implicit-def dead early-clobber %fp, 12, implicit-def dead early-clobber %lr
  
  bb.2:
    INLINEASM $nop, 1, 12, implicit-def dead early-clobber %x0, 12, implicit-def dead early-clobber %x1, 12, implicit-def dead early-clobber %x2, 12, implicit-def dead early-clobber %x3, 12, implicit-def dead early-clobber %x4, 12, implicit-def dead early-clobber %x5, 12, implicit-def dead early-clobber %x6, 12, implicit-def dead early-clobber %x7, 12, implicit-def dead early-clobber %x8, 12, implicit-def dead early-clobber %x9, 12, implicit-def dead early-clobber %x10, 12, implicit-def dead early-clobber %x11, 12, implicit-def dead early-clobber %x12, 12, implicit-def dead early-clobber %x13, 12, implicit-def dead early-clobber %x14, 12, implicit-def dead early-clobber %x15, 12, implicit-def dead early-clobber %x16, 12, implicit-def dead early-clobber %x17, 12, implicit-def dead early-clobber %x18, 12, implicit-def dead early-clobber %x19, 12, implicit-def dead early-clobber %x20, 12, implicit-def dead early-clobber %x21, 12, implicit-def dead early-clobber %x22, 12, implicit-def dead early-clobber %x23, 12, implicit-def dead early-clobber %x24, 12, implicit-def dead early-clobber %x25, 12, implicit-def dead early-clobber %x26, 12, implicit-def dead early-clobber %x27, 12, implicit-def dead early-clobber %x28, 12, implicit-def dead early-clobber %fp, 12, implicit-def dead early-clobber %lr
    %6 = ADRP target-flags(aarch64-page) @g
    %w0 = MOVi32imm 42
    STRWui %8, %6, target-flags(aarch64-pageoff, aarch64-nc) @g :: (volatile store 4 into @g)
    STRXui %9, %6, target-flags(aarch64-pageoff, aarch64-nc) @g :: (volatile store 8 into @g)
    RET_ReallyLR implicit killed %w0

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