; LLVM IR from UtkarshPathrabe/Competitive-Coding :: Model Algorithms/Backtracking/N Queens.ll (Z13NQueenUtilityi)

; 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"

@n = external dso_local global i32, align 4
@board = external dso_local global [100 x [100 x i32]], align 16

; 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: mustprogress nounwind uwtable
declare dso_local noundef zeroext i1 @_Z6IsSafeii(i32 noundef, i32 noundef) #1

; Function Attrs: mustprogress uwtable
define dso_local noundef zeroext i1 @_Z13NQueenUtilityi(i32 noundef %0) #2 {
  %2 = alloca i1, align 1
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  store i32 %0, ptr %3, align 4, !tbaa !5
  %6 = load i32, ptr %3, align 4, !tbaa !5
  %7 = load i32, ptr @n, align 4, !tbaa !5
  %8 = icmp sge i32 %6, %7
  br i1 %8, label %9, label %10

9:                                                ; preds = %1
  store i1 true, ptr %2, align 1
  br label %46

10:                                               ; preds = %1
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #3
  store i32 0, ptr %4, align 4, !tbaa !5
  br label %11

11:                                               ; preds = %40, %10
  %12 = load i32, ptr %4, align 4, !tbaa !5
  %13 = load i32, ptr @n, align 4, !tbaa !5
  %14 = icmp slt i32 %12, %13
  br i1 %14, label %16, label %15

15:                                               ; preds = %11
  store i32 2, ptr %5, align 4
  br label %43

16:                                               ; preds = %11
  %17 = load i32, ptr %4, align 4, !tbaa !5
  %18 = load i32, ptr %3, align 4, !tbaa !5
  %19 = call noundef zeroext i1 @_Z6IsSafeii(i32 noundef %17, i32 noundef %18)
  br i1 %19, label %20, label %39

20:                                               ; preds = %16
  %21 = load i32, ptr %4, align 4, !tbaa !5
  %22 = sext i32 %21 to i64
  %23 = getelementptr inbounds [100 x [100 x i32]], ptr @board, i64 0, i64 %22
  %24 = load i32, ptr %3, align 4, !tbaa !5
  %25 = sext i32 %24 to i64
  %26 = getelementptr inbounds [100 x i32], ptr %23, i64 0, i64 %25
  store i32 1, ptr %26, align 4, !tbaa !5
  %27 = load i32, ptr %3, align 4, !tbaa !5
  %28 = add nsw i32 %27, 1
  %29 = call noundef zeroext i1 @_Z13NQueenUtilityi(i32 noundef %28)
  br i1 %29, label %30, label %31

30:                                               ; preds = %20
  store i1 true, ptr %2, align 1
  store i32 1, ptr %5, align 4
  br label %43

31:                                               ; preds = %20
  %32 = load i32, ptr %4, align 4, !tbaa !5
  %33 = sext i32 %32 to i64
  %34 = getelementptr inbounds [100 x [100 x i32]], ptr @board, i64 0, i64 %33
  %35 = load i32, ptr %3, align 4, !tbaa !5
  %36 = sext i32 %35 to i64
  %37 = getelementptr inbounds [100 x i32], ptr %34, i64 0, i64 %36
  store i32 0, ptr %37, align 4, !tbaa !5
  br label %38

38:                                               ; preds = %31
  br label %39

39:                                               ; preds = %38, %16
  br label %40

40:                                               ; preds = %39
  %41 = load i32, ptr %4, align 4, !tbaa !5
  %42 = add nsw i32 %41, 1
  store i32 %42, ptr %4, align 4, !tbaa !5
  br label %11, !llvm.loop !9

43:                                               ; preds = %30, %15
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #3
  %44 = load i32, ptr %5, align 4
  switch i32 %44, label %48 [
    i32 2, label %45
    i32 1, label %46
  ]

45:                                               ; preds = %43
  store i1 false, ptr %2, align 1
  br label %46

46:                                               ; preds = %45, %43, %9
  %47 = load i1, ptr %2, align 1
  ret i1 %47

48:                                               ; preds = %43
  unreachable
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { mustprogress 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 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 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = distinct !{!9, !10}
!10 = !{!"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"

@n = external dso_local local_unnamed_addr global i32, align 4
@board = external dso_local local_unnamed_addr global [100 x [100 x i32]], align 16

; Function Attrs: mustprogress nounwind uwtable
declare dso_local noundef zeroext i1 @_Z6IsSafeii(i32 noundef, i32 noundef) local_unnamed_addr #0

; Function Attrs: mustprogress nounwind uwtable
define dso_local noundef zeroext i1 @_Z13NQueenUtilityi(i32 noundef %0) local_unnamed_addr #0 {
  %2 = load i32, ptr @n, align 4, !tbaa !5
  %.not = icmp sgt i32 %2, %0
  br i1 %.not, label %.preheader, label %.loopexit

.preheader:                                       ; preds = %1
  %.not1415 = icmp sgt i32 %2, 0
  br i1 %.not1415, label %.lr.ph, label %.loopexit

.lr.ph:                                           ; preds = %.preheader
  %3 = sext i32 %0 to i64
  %4 = add nsw i32 %0, 1
  br label %5

5:                                                ; preds = %.lr.ph, %12
  %indvars.iv = phi i64 [ 0, %.lr.ph ], [ %indvars.iv.next, %12 ]
  %6 = trunc nuw nsw i64 %indvars.iv to i32
  %7 = tail call noundef zeroext i1 @_Z6IsSafeii(i32 noundef %6, i32 noundef %0)
  br i1 %7, label %8, label %12

8:                                                ; preds = %5
  %9 = getelementptr inbounds [100 x [100 x i32]], ptr @board, i64 0, i64 %indvars.iv, i64 %3
  store i32 1, ptr %9, align 4, !tbaa !5
  %10 = tail call noundef zeroext i1 @_Z13NQueenUtilityi(i32 noundef %4)
  br i1 %10, label %.loopexit, label %11

11:                                               ; preds = %8
  store i32 0, ptr %9, align 4, !tbaa !5
  br label %12

12:                                               ; preds = %5, %11
  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
  %13 = load i32, ptr @n, align 4, !tbaa !5
  %14 = sext i32 %13 to i64
  %.not14 = icmp slt i64 %indvars.iv.next, %14
  br i1 %.not14, label %5, label %.loopexit, !llvm.loop !9

.loopexit:                                        ; preds = %8, %12, %.preheader, %1
  %.1 = phi i1 [ true, %1 ], [ false, %.preheader ], [ true, %8 ], [ false, %12 ]
  ret i1 %.1
}

attributes #0 = { mustprogress 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 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = distinct !{!9, !10}
!10 = !{!"llvm.loop.mustprogress"}


; Effective O3 passes: ConstraintEliminationPass,CorrelatedValuePropagationPass,EarlyCSEPass,GVNPass,GlobalOptPass,IPSCCPPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,JumpThreadingPass,LICMPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass