; LLVM IR from irobot-ros/ros2-performance :: performance_test/src/utils/fork_process.ll (ZN16performance_test12fork_processEm)

; Unoptimized IR (clang -disable-llvm-passes):
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

; Function Attrs: mustprogress nounwind uwtable
define dso_local noundef i64 @_ZN16performance_test12fork_processEm(i64 noundef %0) #0 {
  %2 = alloca i64, align 8
  %3 = alloca i32, align 4
  %4 = alloca i64, align 8
  store i64 %0, ptr %2, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #3
  %5 = call i32 @getpid() #3
  store i32 %5, ptr %3, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #3
  store i64 0, ptr %4, align 8, !tbaa !5
  store i64 0, ptr %4, align 8, !tbaa !5
  br label %6

6:                                                ; preds = %23, %1
  %7 = load i64, ptr %4, align 8, !tbaa !5
  %8 = load i64, ptr %2, align 8, !tbaa !5
  %9 = icmp ult i64 %7, %8
  br i1 %9, label %10, label %26

10:                                               ; preds = %6
  %11 = load i64, ptr %4, align 8, !tbaa !5
  %12 = load i64, ptr %2, align 8, !tbaa !5
  %13 = sub i64 %12, 1
  %14 = icmp ne i64 %11, %13
  br i1 %14, label %15, label %21

15:                                               ; preds = %10
  %16 = call i32 @fork() #3
  store i32 %16, ptr %3, align 4, !tbaa !9
  %17 = load i32, ptr %3, align 4, !tbaa !9
  %18 = icmp eq i32 %17, 0
  br i1 %18, label %19, label %20

19:                                               ; preds = %15
  br label %26

20:                                               ; preds = %15
  br label %22

21:                                               ; preds = %10
  br label %26

22:                                               ; preds = %20
  br label %23

23:                                               ; preds = %22
  %24 = load i64, ptr %4, align 8, !tbaa !5
  %25 = add i64 %24, 1
  store i64 %25, ptr %4, align 8, !tbaa !5
  br label %6, !llvm.loop !11

26:                                               ; preds = %21, %19, %6
  %27 = load i64, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #3
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #3
  ret i64 %27
}

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #1

; Function Attrs: nounwind
declare i32 @getpid() #2

; Function Attrs: nounwind
declare i32 @fork() #2

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #1

attributes #0 = { mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #2 = { nounwind "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
attributes #3 = { nounwind }

!llvm.module.flags = !{!0, !1, !2, !3}
!llvm.ident = !{!4}

!0 = !{i32 1, !"wchar_size", i32 4}
!1 = !{i32 8, !"PIC Level", i32 2}
!2 = !{i32 7, !"PIE Level", i32 2}
!3 = !{i32 7, !"uwtable", i32 2}
!4 = !{!"clang version 19.1.0 (git@github.com:llvm/llvm-project.git a4bf6cd7cfb1a1421ba92bca9d017b49936c55e4)"}
!5 = !{!6, !6, i64 0}
!6 = !{!"long", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = !{!10, !10, i64 0}
!10 = !{!"int", !7, i64 0}
!11 = distinct !{!11, !12}
!12 = !{!"llvm.loop.mustprogress"}


; Optimized IR (opt -passes='default<O3>'):
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

; Function Attrs: mustprogress nounwind uwtable
define dso_local noundef i64 @_ZN16performance_test12fork_processEm(i64 noundef %0) local_unnamed_addr #0 {
  %2 = tail call i32 @getpid() #4
  %or.cond9 = icmp ult i64 %0, 2
  br i1 %or.cond9, label %._crit_edge, label %.lr.ph.preheader

.lr.ph.preheader:                                 ; preds = %1
  %3 = add i64 %0, -1
  %4 = add i64 %0, -2
  %umin = tail call i64 @llvm.umin.i64(i64 %3, i64 %4)
  %5 = add nuw i64 %umin, 1
  br label %.lr.ph

.lr.ph:                                           ; preds = %.lr.ph.preheader, %8
  %.010 = phi i64 [ %9, %8 ], [ 0, %.lr.ph.preheader ]
  %6 = tail call i32 @fork() #4
  %7 = icmp eq i32 %6, 0
  br i1 %7, label %._crit_edge, label %8

8:                                                ; preds = %.lr.ph
  %9 = add nuw i64 %.010, 1
  %exitcond = icmp eq i64 %.010, %umin
  br i1 %exitcond, label %._crit_edge, label %.lr.ph, !llvm.loop !5

._crit_edge:                                      ; preds = %8, %.lr.ph, %1
  %.0.lcssa = phi i64 [ 0, %1 ], [ %.010, %.lr.ph ], [ %5, %8 ]
  ret i64 %.0.lcssa
}

; Function Attrs: nounwind
declare i32 @getpid() local_unnamed_addr #1

; Function Attrs: nofree nounwind
declare i32 @fork() local_unnamed_addr #2

; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
declare i64 @llvm.umin.i64(i64, i64) #3

attributes #0 = { mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
attributes #1 = { nounwind "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
attributes #2 = { nofree nounwind "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
attributes #3 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }
attributes #4 = { nounwind }

!llvm.module.flags = !{!0, !1, !2, !3}
!llvm.ident = !{!4}

!0 = !{i32 1, !"wchar_size", i32 4}
!1 = !{i32 8, !"PIC Level", i32 2}
!2 = !{i32 7, !"PIE Level", i32 2}
!3 = !{i32 7, !"uwtable", i32 2}
!4 = !{!"clang version 19.1.0 (git@github.com:llvm/llvm-project.git a4bf6cd7cfb1a1421ba92bca9d017b49936c55e4)"}
!5 = distinct !{!5, !6}
!6 = !{!"llvm.loop.mustprogress"}


; Effective O3 passes: CorrelatedValuePropagationPass,GVNPass,GlobalOptPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,JumpThreadingPass,LCSSAPass,LICMPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,SROAPass,SimplifyCFGPass,TailCallElimPass