; LLVM IR from brewlin/garbage-collect :: mark-sweep (mark_sweep)

; 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"

%struct.root_ = type { ptr, ptr }

@root_used = external global i64, align 8
@roots = external global [100000 x %struct.root_], align 16

; Function Attrs: nounwind uwtable
declare dso_local void @gc_mark(ptr noundef) #0

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

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

; Function Attrs: nounwind uwtable
declare dso_local void @gc_sweep() #0

; Function Attrs: nounwind uwtable
define dso_local void @gc() #0 {
  %1 = alloca i32, align 4
  call void @llvm.lifetime.start.p0(i64 4, ptr %1) #2
  store i32 0, ptr %1, align 4, !tbaa !5
  br label %2

2:                                                ; preds = %14, %0
  %3 = load i32, ptr %1, align 4, !tbaa !5
  %4 = sext i32 %3 to i64
  %5 = load i64, ptr @root_used, align 8, !tbaa !9
  %6 = icmp ult i64 %4, %5
  br i1 %6, label %8, label %7

7:                                                ; preds = %2
  call void @llvm.lifetime.end.p0(i64 4, ptr %1) #2
  br label %17

8:                                                ; preds = %2
  %9 = load i32, ptr %1, align 4, !tbaa !5
  %10 = sext i32 %9 to i64
  %11 = getelementptr inbounds [100000 x %struct.root_], ptr @roots, i64 0, i64 %10
  %12 = getelementptr inbounds %struct.root_, ptr %11, i32 0, i32 0
  %13 = load ptr, ptr %12, align 16, !tbaa !11
  call void @gc_mark(ptr noundef %13)
  br label %14

14:                                               ; preds = %8
  %15 = load i32, ptr %1, align 4, !tbaa !5
  %16 = add nsw i32 %15, 1
  store i32 %16, ptr %1, align 4, !tbaa !5
  br label %2, !llvm.loop !14

17:                                               ; preds = %7
  call void @gc_sweep()
  ret void
}

attributes #0 = { 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 }

!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 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}
!9 = !{!10, !10, i64 0}
!10 = !{!"long", !7, i64 0}
!11 = !{!12, !13, i64 0}
!12 = !{!"root_", !13, i64 0, !13, i64 8}
!13 = !{!"any pointer", !7, i64 0}
!14 = distinct !{!14, !15}
!15 = !{!"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"

%struct.root_ = type { ptr, ptr }

@root_used = external local_unnamed_addr global i64, align 8
@roots = external local_unnamed_addr global [100000 x %struct.root_], align 16

; Function Attrs: nounwind uwtable
declare dso_local void @gc_mark(ptr noundef) local_unnamed_addr #0

; Function Attrs: nounwind uwtable
declare dso_local void @gc_sweep() local_unnamed_addr #0

; Function Attrs: nounwind uwtable
define dso_local void @gc() local_unnamed_addr #0 {
  %1 = load i64, ptr @root_used, align 8, !tbaa !5
  %.not = icmp eq i64 %1, 0
  br i1 %.not, label %._crit_edge, label %.lr.ph

._crit_edge:                                      ; preds = %.lr.ph, %0
  tail call void @gc_sweep()
  ret void

.lr.ph:                                           ; preds = %0, %.lr.ph
  %indvars.iv = phi i64 [ %indvars.iv.next, %.lr.ph ], [ 0, %0 ]
  %2 = getelementptr inbounds [100000 x %struct.root_], ptr @roots, i64 0, i64 %indvars.iv
  %3 = load ptr, ptr %2, align 16, !tbaa !9
  tail call void @gc_mark(ptr noundef %3)
  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
  %4 = load i64, ptr @root_used, align 8, !tbaa !5
  %5 = icmp ugt i64 %4, %indvars.iv.next
  br i1 %5, label %.lr.ph, label %._crit_edge, !llvm.loop !12
}

attributes #0 = { 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" }

!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/C++ TBAA"}
!9 = !{!10, !11, i64 0}
!10 = !{!"root_", !11, i64 0, !11, i64 8}
!11 = !{!"any pointer", !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"llvm.loop.mustprogress"}


; Effective O3 passes: EarlyCSEPass,GlobalOptPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,JumpThreadingPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,SROAPass,SimplifyCFGPass,TailCallElimPass