peephole-opt-check-cflags.mir 1.62 KB
# RUN: llc %s -o - -run-pass=peephole-opt | FileCheck %s

# Check that we don't optimize out a subs due to areCFlagsAccessedBetweenInstrs
# returning the wrong result; it should check the cneg before the subs which does
# modify cflags.

# CHECK-LABEL: f
# CHECK:      SUBSWrr
# CHECK-NEXT: SUBWrr
# CHECK-NEXT: CSNEGWr
# CHECK-NEXT: SUBSWri
# CHECK-NEXT: CSNEGWr
# CHECK-NEXT: Bcc

--- |
  target datalayout = "e-m:w-p:64:64-i32:32-i64:64-i128:128-n32:64-S128"
  target triple = "aarch64-w64-windows-gnu"

  define dso_local void @f() {
    ret void
  }

...
---
name:            f
registers:
  - { id: 43, class: gpr32, preferred-register: '' }
  - { id: 44, class: gpr32, preferred-register: '' }
  - { id: 46, class: gpr32, preferred-register: '' }
  - { id: 47, class: gpr32, preferred-register: '' }
  - { id: 48, class: gpr32common, preferred-register: '' }
  - { id: 49, class: gpr32common, preferred-register: '' }
  - { id: 50, class: gpr32, preferred-register: '' }
  - { id: 51, class: gpr32, preferred-register: '' }
  - { id: 52, class: gpr32, preferred-register: '' }
  - { id: 53, class: gpr32, preferred-register: '' }
body:             |
  bb.0:
    successors: %bb.0

    %43 = MOVi32imm 1
    %44 = MOVi32imm 1
    %46 = MOVi32imm 1
    %47 = MOVi32imm 1
    %48 = nsw SUBSWrr killed %43, killed %46, implicit-def dead $nzcv
    %49 = nsw SUBSWrr killed %44, killed %47, implicit-def dead $nzcv
    %50 = SUBSWri %48, 0, 0, implicit-def $nzcv
    %51 = CSNEGWr %48, %48, 5, implicit $nzcv
    %52 = SUBSWri %49, 0, 0, implicit-def $nzcv
    %53 = CSNEGWr %49, %49, 5, implicit $nzcv
    Bcc 1, %bb.0, implicit $nzcv
    RET_ReallyLR

...