llvm-project/llvm/test/CodeGen/X86/pr27681.mir

# RUN: llc -mtriple=i386-unknown-linux-gnu -mcpu=slm -run-pass post-RA-sched -o - %s | FileCheck %s
#
# Verify that the critical antidependence breaker does not consider
# a high byte register as available as a replacement register
# in a certain context.
--- |

  define void @main() { ret void }

...
---
# CHECK-LABEL: main
name:            main
tracksRegLiveness: true
frameInfo:
  stackSize:       52
fixedStack:
  - { id: 0, type: spill-slot, offset: -20, size: 4, alignment: 4, callee-saved-register: '$esi' }
  - { id: 1, type: spill-slot, offset: -16, size: 4, alignment: 4, callee-saved-register: '$edi' }
  - { id: 2, type: spill-slot, offset: -12, size: 4, alignment: 4, callee-saved-register: '$ebx' }
  - { id: 3, type: spill-slot, offset: -8, size: 4, alignment: 4, callee-saved-register: '$ebp' }
stack:
  - { id: 0, type: spill-slot, offset: -53, size: 1, alignment: 1 }
  - { id: 1, type: spill-slot, offset: -48, size: 4, alignment: 4 }
  - { id: 2, type: spill-slot, offset: -32, size: 4, alignment: 4 }
body:             |
  bb.0:
    liveins: $ebp, $ebx, $edi, $esi

    frame-setup PUSH32r killed $ebp, implicit-def $esp, implicit $esp
    frame-setup PUSH32r killed $ebx, implicit-def $esp, implicit $esp
    frame-setup PUSH32r killed $edi, implicit-def $esp, implicit $esp
    frame-setup PUSH32r killed $esi, implicit-def $esp, implicit $esp
    $esp = frame-setup SUB32ri8 $esp, 36, implicit-def dead $eflags
    $eax = MOV32ri 1
    $ebp = MOV32ri 2
    $ebx = MOV32ri 3
    $ecx = MOV32ri 4
    $edi = MOV32ri 5
    $edx = MOV32ri 6

  bb.1:
    liveins: $eax, $ebp, $ebx, $ecx, $edi, $edx

    $ebp = SHR32rCL killed $ebp, implicit-def dead $eflags, implicit $cl
    $ebp = XOR32rr killed $ebp, killed $ebx, implicit-def dead $eflags
    TEST32rr $edx, $edx, implicit-def $eflags
    $cl = SETCCr 5, implicit $eflags
    ; This %bl def is antidependent on the above use of $ebx
    $bl = MOV8rm $esp, 1, $noreg, 3, _ ; :: (load 1 from %stack.0)
    $cl = OR8rr killed $cl, $bl, implicit-def dead $eflags
    $esi = MOVZX32rr8 killed $cl
    $esi = ADD32rr killed $esi, killed $edi, implicit-def dead $eflags
    $ecx = MOV32rm $esp, 1, $noreg, 24, _ ; :: (load 4 from %stack.2)
    $edx = SAR32rCL killed $edx, implicit-def dead $eflags, implicit $cl
    TEST32rr killed $edx, $edx, implicit-def $eflags
    $cl = SETCCr 5, implicit $eflags
    ; Verify that removal of the $bl antidependence does not use $ch
    ; as a replacement register.
    ; CHECK: $cl = AND8rr killed $cl, killed $b
    $cl = AND8rr killed $cl, killed $bl, implicit-def dead $eflags
    CMP32ri8 $ebp, -1, implicit-def $eflags
    $edx = MOV32ri 0
    JE_1 %bb.3, implicit $eflags

  bb.2:
    liveins: $cl, $eax, $ebp, $esi

    OR32mr $esp, 1, $noreg, 8, $noreg, killed $eax, implicit-def $eflags ; :: (store 4 into %stack.1)
    $dl = SETCCr 5, implicit $eflags, implicit-def $edx

  bb.3:
    liveins: $cl, $ebp, $edx, $esi

    $eax = XOR32rr undef $eax, undef $eax, implicit-def dead $eflags
    $esp = ADD32ri8 $esp, 36, implicit-def dead $eflags
    $esi = POP32r implicit-def $esp, implicit $esp
    $edi = POP32r implicit-def $esp, implicit $esp
    $ebx = POP32r implicit-def $esp, implicit $esp
    $ebp = POP32r implicit-def $esp, implicit $esp
    RET 0, $eax

...