; LLVM IR from codemistic/Data-Structures-and-Algorithms :: CPP/Trees/Expression_tree (Stack)

; 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.StackNode = type { ptr, ptr }

; Function Attrs: nounwind uwtable
define dso_local i32 @pop(ptr noundef %0) #0 {
  %2 = alloca i32, align 4
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  store ptr %0, ptr %3, align 8, !tbaa !5
  %5 = load ptr, ptr %3, align 8, !tbaa !5
  %6 = load ptr, ptr %5, align 8, !tbaa !5
  %7 = icmp eq ptr %6, null
  br i1 %7, label %8, label %9

8:                                                ; preds = %1
  store i32 1, ptr %2, align 4
  br label %26

9:                                                ; preds = %1
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #3
  store ptr null, ptr %4, align 8, !tbaa !5
  %10 = load ptr, ptr %3, align 8, !tbaa !5
  %11 = load ptr, ptr %10, align 8, !tbaa !5
  %12 = getelementptr inbounds %struct.StackNode, ptr %11, i32 0, i32 0
  %13 = load ptr, ptr %12, align 8, !tbaa !9
  %14 = icmp ne ptr %13, null
  br i1 %14, label %15, label %20

15:                                               ; preds = %9
  %16 = load ptr, ptr %3, align 8, !tbaa !5
  %17 = load ptr, ptr %16, align 8, !tbaa !5
  %18 = getelementptr inbounds %struct.StackNode, ptr %17, i32 0, i32 0
  %19 = load ptr, ptr %18, align 8, !tbaa !9
  store ptr %19, ptr %4, align 8, !tbaa !5
  br label %20

20:                                               ; preds = %15, %9
  %21 = load ptr, ptr %3, align 8, !tbaa !5
  %22 = load ptr, ptr %21, align 8, !tbaa !5
  call void @free(ptr noundef %22) #3
  %23 = load ptr, ptr %4, align 8, !tbaa !5
  %24 = load ptr, ptr %3, align 8, !tbaa !5
  store ptr %23, ptr %24, align 8, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #3
  br label %25

25:                                               ; preds = %20
  store i32 0, ptr %2, align 4
  br label %26

26:                                               ; preds = %25, %8
  %27 = load i32, ptr %2, align 4
  ret i32 %27
}

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

; Function Attrs: nounwind
declare void @free(ptr noundef) #2

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

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 "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 0}
!10 = !{!"StackNode", !6, i64 0, !6, i64 8}


; 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"

; Function Attrs: mustprogress nounwind willreturn uwtable
define dso_local range(i32 0, 2) i32 @pop(ptr nocapture noundef %0) local_unnamed_addr #0 {
  %2 = load ptr, ptr %0, align 8, !tbaa !5
  %3 = icmp eq ptr %2, null
  br i1 %3, label %6, label %4

4:                                                ; preds = %1
  %5 = load ptr, ptr %2, align 8, !tbaa !9
  tail call void @free(ptr noundef nonnull %2) #2
  store ptr %5, ptr %0, align 8, !tbaa !5
  br label %6

6:                                                ; preds = %1, %4
  %.06 = phi i32 [ 0, %4 ], [ 1, %1 ]
  ret i32 %.06
}

; Function Attrs: mustprogress nounwind willreturn allockind("free") memory(argmem: readwrite, inaccessiblemem: readwrite)
declare void @free(ptr allocptr nocapture noundef) local_unnamed_addr #1

attributes #0 = { mustprogress nounwind willreturn 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 = { 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 #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 = !{!"any pointer", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}
!9 = !{!10, !6, i64 0}
!10 = !{!"StackNode", !6, i64 0, !6, i64 8}


; Effective O3 passes: CorrelatedValuePropagationPass,EarlyCSEPass,GlobalOptPass,IPSCCPPass,InferFunctionAttrsPass,InstCombinePass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass