; LLVM IR from ritikbanger/Hacktoberfest2022-DSA :: 36. C Programs (doubly_linkedlist)

; 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 }

@.str.6 = external hidden unnamed_addr constant [12 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 @delete_from_end(ptr noundef %0) #2 {
  %2 = alloca ptr, align 8
  %3 = alloca ptr, align 8
  store ptr %0, ptr %2, align 8, !tbaa !5
  %4 = load ptr, ptr %2, align 8, !tbaa !5
  %5 = load ptr, ptr %4, align 8, !tbaa !5
  %6 = icmp eq ptr %5, null
  br i1 %6, label %7, label %9

7:                                                ; preds = %1
  %8 = call i32 (ptr, ...) @printf(ptr noundef @.str.6)
  br label %26

9:                                                ; preds = %1
  call void @llvm.lifetime.start.p0(i64 8, ptr %3) #3
  %10 = load ptr, ptr %2, align 8, !tbaa !5
  %11 = load ptr, ptr %10, align 8, !tbaa !5
  store ptr %11, ptr %3, align 8, !tbaa !5
  br label %12

12:                                               ; preds = %19, %9
  %13 = load ptr, ptr %3, align 8, !tbaa !5
  %14 = getelementptr inbounds %struct.node, ptr %13, i32 0, i32 2
  %15 = load ptr, ptr %14, align 8, !tbaa !9
  %16 = getelementptr inbounds %struct.node, ptr %15, i32 0, i32 2
  %17 = load ptr, ptr %16, align 8, !tbaa !9
  %18 = icmp ne ptr %17, null
  br i1 %18, label %19, label %23

19:                                               ; preds = %12
  %20 = load ptr, ptr %3, align 8, !tbaa !5
  %21 = getelementptr inbounds %struct.node, ptr %20, i32 0, i32 2
  %22 = load ptr, ptr %21, align 8, !tbaa !9
  store ptr %22, ptr %3, align 8, !tbaa !5
  br label %12, !llvm.loop !12

23:                                               ; preds = %12
  %24 = load ptr, ptr %3, align 8, !tbaa !5
  %25 = getelementptr inbounds %struct.node, ptr %24, i32 0, i32 2
  store ptr null, ptr %25, align 8, !tbaa !9
  call void @llvm.lifetime.end.p0(i64 8, ptr %3) #3
  br label %26

26:                                               ; preds = %23, %7
  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, !6, i64 16}
!10 = !{!"node", !11, i64 0, !6, i64 8, !6, i64 16}
!11 = !{!"int", !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"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"

@.str.6 = external hidden unnamed_addr constant [12 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 @delete_from_end(ptr nocapture noundef readonly %0) local_unnamed_addr #1 {
  %2 = load ptr, ptr %0, align 8, !tbaa !5
  %3 = icmp eq ptr %2, null
  br i1 %3, label %4, label %.preheader.preheader

.preheader.preheader:                             ; preds = %1
  %.phi.trans.insert = getelementptr inbounds i8, ptr %2, i64 16
  %.pre = load ptr, ptr %.phi.trans.insert, align 8, !tbaa !9
  br label %.preheader

4:                                                ; preds = %1
  %5 = tail call i32 (ptr, ...) @printf(ptr noundef nonnull dereferenceable(1) @.str.6)
  br label %11

.preheader:                                       ; preds = %.preheader.preheader, %.preheader
  %6 = phi ptr [ %8, %.preheader ], [ %.pre, %.preheader.preheader ]
  %.0 = phi ptr [ %6, %.preheader ], [ %2, %.preheader.preheader ]
  %7 = getelementptr inbounds i8, ptr %6, i64 16
  %8 = load ptr, ptr %7, align 8, !tbaa !9
  %.not = icmp eq ptr %8, null
  br i1 %.not, label %9, label %.preheader, !llvm.loop !12

9:                                                ; preds = %.preheader
  %10 = getelementptr inbounds i8, ptr %.0, i64 16
  store ptr null, ptr %10, align 8, !tbaa !9
  br label %11

11:                                               ; preds = %9, %4
  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, !6, i64 16}
!10 = !{!"node", !11, i64 0, !6, i64 8, !6, i64 16}
!11 = !{!"int", !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"llvm.loop.mustprogress"}


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