; LLVM IR from JessonYue/LeetCodeLearning :: Array/caiweixiong/c (homework_011)

; 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.Queue = type { ptr, ptr }
%struct.ListNode = type { i32, ptr }

; Function Attrs: nounwind uwtable
define dso_local i32 @myStackTop(ptr noundef %0) #0 {
  %2 = alloca i32, align 4
  %3 = alloca ptr, align 8
  store ptr %0, ptr %3, align 8, !tbaa !5
  %4 = load ptr, ptr %3, align 8, !tbaa !5
  %5 = icmp ne ptr %4, null
  br i1 %5, label %6, label %16

6:                                                ; preds = %1
  %7 = load ptr, ptr %3, align 8, !tbaa !5
  %8 = getelementptr inbounds %struct.Queue, ptr %7, i32 0, i32 1
  %9 = load ptr, ptr %8, align 8, !tbaa !9
  %10 = icmp ne ptr %9, null
  br i1 %10, label %17, label %11

11:                                               ; preds = %6
  %12 = load ptr, ptr %3, align 8, !tbaa !5
  %13 = getelementptr inbounds %struct.Queue, ptr %12, i32 0, i32 0
  %14 = load ptr, ptr %13, align 8, !tbaa !11
  %15 = icmp ne ptr %14, null
  br i1 %15, label %17, label %16

16:                                               ; preds = %11, %1
  store i32 0, ptr %2, align 4
  br label %23

17:                                               ; preds = %11, %6
  %18 = load ptr, ptr %3, align 8, !tbaa !5
  %19 = getelementptr inbounds %struct.Queue, ptr %18, i32 0, i32 0
  %20 = load ptr, ptr %19, align 8, !tbaa !11
  %21 = getelementptr inbounds %struct.ListNode, ptr %20, i32 0, i32 0
  %22 = load i32, ptr %21, align 8, !tbaa !12
  store i32 %22, ptr %2, align 4
  br label %23

23:                                               ; preds = %17, %16
  %24 = load i32, ptr %2, align 4
  ret i32 %24
}

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" }

!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 = !{!"Queue", !6, i64 0, !6, i64 8}
!11 = !{!10, !6, i64 0}
!12 = !{!13, !14, i64 0}
!13 = !{!"ListNode", !14, i64 0, !6, i64 8}
!14 = !{!"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"

; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(read, inaccessiblemem: none) uwtable
define dso_local i32 @myStackTop(ptr noundef readonly %0) local_unnamed_addr #0 {
  %.not = icmp eq ptr %0, null
  br i1 %.not, label %7, label %2

2:                                                ; preds = %1
  %3 = getelementptr inbounds i8, ptr %0, i64 8
  %4 = load ptr, ptr %3, align 8, !tbaa !5
  %.not5 = icmp eq ptr %4, null
  %.pre = load ptr, ptr %0, align 8, !tbaa !10
  %.not6 = icmp eq ptr %.pre, null
  %or.cond = select i1 %.not5, i1 %.not6, i1 false
  br i1 %or.cond, label %7, label %5

5:                                                ; preds = %2
  %6 = load i32, ptr %.pre, align 8, !tbaa !11
  br label %7

7:                                                ; preds = %2, %1, %5
  %.0 = phi i32 [ %6, %5 ], [ 0, %1 ], [ 0, %2 ]
  ret i32 %.0
}

attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn memory(read, 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, !7, i64 8}
!6 = !{!"Queue", !7, i64 0, !7, i64 8}
!7 = !{!"any pointer", !8, i64 0}
!8 = !{!"omnipotent char", !9, i64 0}
!9 = !{!"Simple C/C++ TBAA"}
!10 = !{!6, !7, i64 0}
!11 = !{!12, !13, i64 0}
!12 = !{!"ListNode", !13, i64 0, !7, i64 8}
!13 = !{!"int", !8, i64 0}


; Effective O3 passes: EarlyCSEPass,GVNPass,GlobalOptPass,InstCombinePass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass