; LLVM IR from ritikbanger/Hacktoberfest2022-DSA :: 10. Linked List/c lang/DoublyLinkedList (Deleting)

; 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 }

@start = external dso_local global ptr, align 8

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

; 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 @deletePos(i32 noundef %0) #1 {
  %2 = alloca i32, align 4
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  %5 = alloca i32, align 4
  store i32 %0, ptr %2, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %3) #2
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #2
  %6 = load ptr, ptr @start, align 8, !tbaa !9
  store ptr %6, ptr %3, align 8, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #2
  store i32 1, ptr %5, align 4, !tbaa !5
  br label %7

7:                                                ; preds = %25, %1
  %8 = load ptr, ptr %3, align 8, !tbaa !9
  %9 = icmp ne ptr %8, null
  br i1 %9, label %10, label %32

10:                                               ; preds = %7
  %11 = load i32, ptr %5, align 4, !tbaa !5
  %12 = load i32, ptr %2, align 4, !tbaa !5
  %13 = icmp eq i32 %11, %12
  br i1 %13, label %14, label %25

14:                                               ; preds = %10
  %15 = load ptr, ptr %3, align 8, !tbaa !9
  %16 = getelementptr inbounds %struct.node, ptr %15, i32 0, i32 2
  %17 = load ptr, ptr %16, align 8, !tbaa !11
  %18 = load ptr, ptr %4, align 8, !tbaa !9
  %19 = getelementptr inbounds %struct.node, ptr %18, i32 0, i32 2
  store ptr %17, ptr %19, align 8, !tbaa !11
  %20 = load ptr, ptr %4, align 8, !tbaa !9
  %21 = load ptr, ptr %3, align 8, !tbaa !9
  %22 = getelementptr inbounds %struct.node, ptr %21, i32 0, i32 2
  %23 = load ptr, ptr %22, align 8, !tbaa !11
  %24 = getelementptr inbounds %struct.node, ptr %23, i32 0, i32 1
  store ptr %20, ptr %24, align 8, !tbaa !13
  br label %25

25:                                               ; preds = %14, %10
  %26 = load ptr, ptr %3, align 8, !tbaa !9
  store ptr %26, ptr %4, align 8, !tbaa !9
  %27 = load ptr, ptr %3, align 8, !tbaa !9
  %28 = getelementptr inbounds %struct.node, ptr %27, i32 0, i32 2
  %29 = load ptr, ptr %28, align 8, !tbaa !11
  store ptr %29, ptr %3, align 8, !tbaa !9
  %30 = load i32, ptr %5, align 4, !tbaa !5
  %31 = add nsw i32 %30, 1
  store i32 %31, ptr %5, align 4, !tbaa !5
  br label %7, !llvm.loop !14

32:                                               ; preds = %7
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %3) #2
  ret void
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { 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 #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 = !{!"any pointer", !7, i64 0}
!11 = !{!12, !10, i64 16}
!12 = !{!"node", !6, i64 0, !10, i64 8, !10, i64 16}
!13 = !{!12, !10, i64 8}
!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"

@start = external dso_local local_unnamed_addr global ptr, align 8

; Function Attrs: nofree norecurse nosync nounwind memory(readwrite, inaccessiblemem: none) uwtable
define dso_local void @deletePos(i32 noundef %0) local_unnamed_addr #0 {
  %.01011 = load ptr, ptr @start, align 8, !tbaa !5
  %.not12 = icmp eq ptr %.01011, null
  br i1 %.not12, label %._crit_edge, label %.lr.ph

.lr.ph:                                           ; preds = %1, %8
  %.01015 = phi ptr [ %.010, %8 ], [ %.01011, %1 ]
  %.014 = phi i32 [ %10, %8 ], [ 1, %1 ]
  %.0913 = phi ptr [ %.01015, %8 ], [ undef, %1 ]
  %2 = icmp eq i32 %.014, %0
  br i1 %2, label %3, label %8

3:                                                ; preds = %.lr.ph
  %4 = getelementptr inbounds i8, ptr %.01015, i64 16
  %5 = load ptr, ptr %4, align 8, !tbaa !9
  %6 = getelementptr inbounds i8, ptr %.0913, i64 16
  store ptr %5, ptr %6, align 8, !tbaa !9
  %7 = getelementptr inbounds i8, ptr %5, i64 8
  store ptr %.0913, ptr %7, align 8, !tbaa !12
  br label %8

8:                                                ; preds = %3, %.lr.ph
  %9 = getelementptr inbounds i8, ptr %.01015, i64 16
  %10 = add nuw nsw i32 %.014, 1
  %.010 = load ptr, ptr %9, align 8, !tbaa !5
  %.not = icmp eq ptr %.010, null
  br i1 %.not, label %._crit_edge, label %.lr.ph, !llvm.loop !13

._crit_edge:                                      ; preds = %8, %1
  ret void
}

attributes #0 = { nofree norecurse nosync nounwind memory(readwrite, inaccessiblemem: none) 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, !6, i64 16}
!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,GVNPass,GlobalOptPass,InferFunctionAttrsPass,InstCombinePass,JumpThreadingPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass