; LLVM IR from mahendramahara/DSA-in-C-Programing :: CIRCULAR-LINKED-LIST/CIRCULAR-DOUBLY (DeleteBEG)

; 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.Node = type { i32, ptr, ptr }

@head = external dso_local global ptr, align 8
@.str.1 = external hidden unnamed_addr constant [16 x i8], align 1
@.str.2 = external hidden unnamed_addr constant [30 x i8], align 1
@.str.3 = external hidden unnamed_addr constant [4 x i8], align 1
@.str.4 = external hidden unnamed_addr constant [2 x i8], align 1

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #0

declare i32 @printf(ptr noundef, ...) #1

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #0

; Function Attrs: nounwind uwtable
define dso_local void @displayList() #2 {
  %1 = alloca ptr, align 8
  %2 = load ptr, ptr @head, align 8, !tbaa !5
  %3 = icmp eq ptr %2, null
  br i1 %3, label %4, label %6

4:                                                ; preds = %0
  %5 = call i32 (ptr, ...) @printf(ptr noundef @.str.1)
  br label %23

6:                                                ; preds = %0
  call void @llvm.lifetime.start.p0(i64 8, ptr %1) #3
  %7 = load ptr, ptr @head, align 8, !tbaa !5
  store ptr %7, ptr %1, align 8, !tbaa !5
  %8 = call i32 (ptr, ...) @printf(ptr noundef @.str.2)
  br label %9

9:                                                ; preds = %17, %6
  %10 = load ptr, ptr %1, align 8, !tbaa !5
  %11 = getelementptr inbounds %struct.Node, ptr %10, i32 0, i32 0
  %12 = load i32, ptr %11, align 8, !tbaa !9
  %13 = call i32 (ptr, ...) @printf(ptr noundef @.str.3, i32 noundef %12)
  %14 = load ptr, ptr %1, align 8, !tbaa !5
  %15 = getelementptr inbounds %struct.Node, ptr %14, i32 0, i32 1
  %16 = load ptr, ptr %15, align 8, !tbaa !12
  store ptr %16, ptr %1, align 8, !tbaa !5
  br label %17

17:                                               ; preds = %9
  %18 = load ptr, ptr %1, align 8, !tbaa !5
  %19 = load ptr, ptr @head, align 8, !tbaa !5
  %20 = icmp ne ptr %18, %19
  br i1 %20, label %9, label %21, !llvm.loop !13

21:                                               ; preds = %17
  %22 = call i32 (ptr, ...) @printf(ptr noundef @.str.4)
  call void @llvm.lifetime.end.p0(i64 8, ptr %1) #3
  br label %23

23:                                               ; preds = %21, %4
  ret void
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { "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 = { 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 #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 = !{!"any pointer", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}
!9 = !{!10, !11, i64 0}
!10 = !{!"Node", !11, i64 0, !6, i64 8, !6, i64 16}
!11 = !{!"int", !7, i64 0}
!12 = !{!10, !6, i64 8}
!13 = distinct !{!13, !14}
!14 = !{!"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"

@head = external dso_local local_unnamed_addr global ptr, align 8
@.str.1 = external hidden unnamed_addr constant [16 x i8], align 1
@.str.2 = external hidden unnamed_addr constant [30 x i8], align 1
@.str.3 = external hidden unnamed_addr constant [4 x i8], align 1
@.str.4 = external hidden unnamed_addr constant [2 x i8], align 1

; Function Attrs: nofree nounwind
declare noundef i32 @printf(ptr nocapture noundef readonly, ...) local_unnamed_addr #0

; Function Attrs: nofree nounwind uwtable
define dso_local void @displayList() local_unnamed_addr #1 {
  %1 = load ptr, ptr @head, align 8, !tbaa !5
  %2 = icmp eq ptr %1, null
  br i1 %2, label %.loopexit, label %3

3:                                                ; preds = %0
  %4 = tail call i32 (ptr, ...) @printf(ptr noundef nonnull dereferenceable(1) @.str.2)
  br label %5

5:                                                ; preds = %5, %3
  %.0 = phi ptr [ %1, %3 ], [ %9, %5 ]
  %6 = load i32, ptr %.0, align 8, !tbaa !9
  %7 = tail call i32 (ptr, ...) @printf(ptr noundef nonnull dereferenceable(1) @.str.3, i32 noundef %6)
  %8 = getelementptr inbounds i8, ptr %.0, i64 8
  %9 = load ptr, ptr %8, align 8, !tbaa !12
  %10 = load ptr, ptr @head, align 8, !tbaa !5
  %.not = icmp eq ptr %9, %10
  br i1 %.not, label %.loopexit, label %5, !llvm.loop !13

.loopexit:                                        ; preds = %5, %0
  %.str.4.sink = phi ptr [ @.str.1, %0 ], [ @.str.4, %5 ]
  %11 = tail call i32 (ptr, ...) @printf(ptr noundef nonnull dereferenceable(1) %.str.4.sink)
  ret void
}

attributes #0 = { 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 #1 = { nofree 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 = !{!"any pointer", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}
!9 = !{!10, !11, i64 0}
!10 = !{!"Node", !11, i64 0, !6, i64 8, !6, i64 16}
!11 = !{!"int", !7, i64 0}
!12 = !{!10, !6, i64 8}
!13 = distinct !{!13, !14}
!14 = !{!"llvm.loop.mustprogress"}


; Effective O3 passes: EarlyCSEPass,GlobalOptPass,InferFunctionAttrsPass,InstCombinePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass