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

; 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 }

@.str.33 = external hidden unnamed_addr constant [70 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: nounwind uwtable
declare dso_local i32 @length(ptr noundef) #2

; Function Attrs: nounwind uwtable
define dso_local ptr @delete_first(ptr noundef %0) #2 {
  %2 = alloca ptr, align 8
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  %5 = alloca i32, align 4
  store ptr %0, ptr %3, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #4
  %6 = load ptr, ptr %3, align 8, !tbaa !5
  %7 = getelementptr inbounds %struct.node, ptr %6, i32 0, i32 1
  %8 = load ptr, ptr %7, align 8, !tbaa !9
  store ptr %8, ptr %4, align 8, !tbaa !5
  %9 = load ptr, ptr %3, align 8, !tbaa !5
  %10 = call i32 @length(ptr noundef %9)
  %11 = icmp eq i32 %10, 1
  br i1 %11, label %12, label %15

12:                                               ; preds = %1
  %13 = call i32 (ptr, ...) @printf(ptr noundef @.str.33)
  %14 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %14, ptr %2, align 8
  store i32 1, ptr %5, align 4
  br label %18

15:                                               ; preds = %1
  %16 = load ptr, ptr %3, align 8, !tbaa !5
  call void @free(ptr noundef %16) #4
  %17 = load ptr, ptr %4, align 8, !tbaa !5
  store ptr %17, ptr %2, align 8
  store i32 1, ptr %5, align 4
  br label %18

18:                                               ; preds = %15, %12
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #4
  %19 = load ptr, ptr %2, align 8
  ret ptr %19
}

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

; Function Attrs: nounwind
declare void @free(ptr noundef) #3

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 "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 #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 = !{!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 8}
!10 = !{!"node", !11, i64 0, !6, i64 8}
!11 = !{!"int", !7, i64 0}


; 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.33 = external hidden unnamed_addr constant [70 x i8], align 1

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

; Function Attrs: nounwind uwtable
declare dso_local i32 @length(ptr noundef) local_unnamed_addr #1

; Function Attrs: nounwind uwtable
define dso_local ptr @delete_first(ptr noundef %0) local_unnamed_addr #1 {
  %2 = getelementptr inbounds i8, ptr %0, i64 8
  %3 = load ptr, ptr %2, align 8, !tbaa !5
  %4 = tail call i32 @length(ptr noundef %0)
  %5 = icmp eq i32 %4, 1
  br i1 %5, label %6, label %8

6:                                                ; preds = %1
  %7 = tail call i32 (ptr, ...) @printf(ptr noundef nonnull dereferenceable(1) @.str.33)
  br label %9

8:                                                ; preds = %1
  tail call void @free(ptr noundef nonnull %0) #3
  br label %9

9:                                                ; preds = %8, %6
  %.0 = phi ptr [ %0, %6 ], [ %3, %8 ]
  ret ptr %.0
}

; Function Attrs: mustprogress nounwind willreturn allockind("free") memory(argmem: readwrite, inaccessiblemem: readwrite)
declare void @free(ptr allocptr nocapture noundef) local_unnamed_addr #2

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 = { 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 = { mustprogress nounwind willreturn allockind("free") memory(argmem: readwrite, inaccessiblemem: readwrite) "alloc-family"="malloc" "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, !10, i64 8}
!6 = !{!"node", !7, i64 0, !10, i64 8}
!7 = !{!"int", !8, i64 0}
!8 = !{!"omnipotent char", !9, i64 0}
!9 = !{!"Simple C/C++ TBAA"}
!10 = !{!"any pointer", !8, i64 0}


; Effective O3 passes: CorrelatedValuePropagationPass,GlobalOptPass,InferFunctionAttrsPass,InstCombinePass,SROAPass,TailCallElimPass