; LLVM IR from Muhammad-Magdi/problem-solving :: Backtracking (NQueens)

; 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 [15 x [15 x i8]], align 16
@.str.3 = external hidden unnamed_addr constant [3 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

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

; Function Attrs: mustprogress uwtable
declare dso_local void @_Z7solveNQi(i32 noundef) #1

; Function Attrs: mustprogress norecurse uwtable
define dso_local noundef i32 @main() #2 {
  %1 = alloca i32, align 4
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  store i32 0, ptr %1, align 4
  %5 = call i32 (ptr, ...) @__isoc99_scanf(ptr noundef @.str.3, ptr noundef @n)
  call void @llvm.lifetime.start.p0(i64 4, ptr %2) #4
  store i32 0, ptr %2, align 4, !tbaa !5
  br label %6

6:                                                ; preds = %28, %0
  %7 = load i32, ptr %2, align 4, !tbaa !5
  %8 = load i32, ptr @n, align 4, !tbaa !5
  %9 = icmp slt i32 %7, %8
  br i1 %9, label %11, label %10

10:                                               ; preds = %6
  store i32 2, ptr %3, align 4
  call void @llvm.lifetime.end.p0(i64 4, ptr %2) #4
  br label %31

11:                                               ; preds = %6
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #4
  store i32 0, ptr %4, align 4, !tbaa !5
  br label %12

12:                                               ; preds = %24, %11
  %13 = load i32, ptr %4, align 4, !tbaa !5
  %14 = load i32, ptr @n, align 4, !tbaa !5
  %15 = icmp slt i32 %13, %14
  br i1 %15, label %17, label %16

16:                                               ; preds = %12
  store i32 5, ptr %3, align 4
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #4
  br label %27

17:                                               ; preds = %12
  %18 = load i32, ptr %2, align 4, !tbaa !5
  %19 = sext i32 %18 to i64
  %20 = getelementptr inbounds [15 x [15 x i8]], ptr @board, i64 0, i64 %19
  %21 = load i32, ptr %4, align 4, !tbaa !5
  %22 = sext i32 %21 to i64
  %23 = getelementptr inbounds [15 x i8], ptr %20, i64 0, i64 %22
  store i8 46, ptr %23, align 1, !tbaa !9
  br label %24

24:                                               ; preds = %17
  %25 = load i32, ptr %4, align 4, !tbaa !5
  %26 = add nsw i32 %25, 1
  store i32 %26, ptr %4, align 4, !tbaa !5
  br label %12, !llvm.loop !10

27:                                               ; preds = %16
  br label %28

28:                                               ; preds = %27
  %29 = load i32, ptr %2, align 4, !tbaa !5
  %30 = add nsw i32 %29, 1
  store i32 %30, ptr %2, align 4, !tbaa !5
  br label %6, !llvm.loop !12

31:                                               ; preds = %10
  call void @_Z7solveNQi(i32 noundef 0)
  ret i32 0
}

declare i32 @__isoc99_scanf(ptr noundef, ...) #3

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { 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 #2 = { mustprogress norecurse 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 = { "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 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = !{!7, !7, i64 0}
!10 = distinct !{!10, !11}
!11 = !{!"llvm.loop.mustprogress"}
!12 = distinct !{!12, !11}


; 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 global i32, align 4
@board = external dso_local local_unnamed_addr global [15 x [15 x i8]], align 16
@.str.3 = external hidden unnamed_addr constant [3 x i8], align 1

; Function Attrs: mustprogress uwtable
declare dso_local void @_Z7solveNQi(i32 noundef) local_unnamed_addr #0

; Function Attrs: mustprogress norecurse uwtable
define dso_local noundef i32 @main() local_unnamed_addr #1 {
  %1 = tail call i32 (ptr, ...) @__isoc99_scanf(ptr noundef nonnull @.str.3, ptr noundef nonnull @n)
  %2 = load i32, ptr @n, align 4, !tbaa !5
  %3 = icmp sgt i32 %2, 0
  br i1 %3, label %.preheader.us.preheader, label %._crit_edge9

.preheader.us.preheader:                          ; preds = %0
  %4 = zext nneg i32 %2 to i64
  %xtraiter = and i64 %4, 7
  %5 = icmp ult i32 %2, 8
  br i1 %5, label %._crit_edge9.loopexit.unr-lcssa, label %.preheader.us.preheader.new

.preheader.us.preheader.new:                      ; preds = %.preheader.us.preheader
  %unroll_iter = and i64 %4, 2147483640
  br label %.preheader.us

.preheader.us:                                    ; preds = %.preheader.us, %.preheader.us.preheader.new
  %indvar = phi i64 [ 0, %.preheader.us.preheader.new ], [ %indvar.next.7, %.preheader.us ]
  %niter = phi i64 [ 0, %.preheader.us.preheader.new ], [ %niter.next.7, %.preheader.us ]
  %6 = mul nuw nsw i64 %indvar, 15
  %scevgep = getelementptr i8, ptr @board, i64 %6
  tail call void @llvm.memset.p0.i64(ptr align 8 %scevgep, i8 46, i64 %4, i1 false), !tbaa !9
  %7 = mul nuw i64 %indvar, 15
  %gep = getelementptr i8, ptr getelementptr (i8, ptr @board, i64 15), i64 %7
  tail call void @llvm.memset.p0.i64(ptr align 1 %gep, i8 46, i64 %4, i1 false), !tbaa !9
  %8 = mul nuw i64 %indvar, 15
  %gep12 = getelementptr i8, ptr getelementptr (i8, ptr @board, i64 30), i64 %8
  tail call void @llvm.memset.p0.i64(ptr align 2 %gep12, i8 46, i64 %4, i1 false), !tbaa !9
  %9 = mul nuw i64 %indvar, 15
  %gep13 = getelementptr i8, ptr getelementptr (i8, ptr @board, i64 45), i64 %9
  tail call void @llvm.memset.p0.i64(ptr align 1 %gep13, i8 46, i64 %4, i1 false), !tbaa !9
  %10 = mul nuw i64 %indvar, 15
  %gep14 = getelementptr i8, ptr getelementptr (i8, ptr @board, i64 60), i64 %10
  tail call void @llvm.memset.p0.i64(ptr align 4 %gep14, i8 46, i64 %4, i1 false), !tbaa !9
  %11 = mul nuw i64 %indvar, 15
  %gep15 = getelementptr i8, ptr getelementptr (i8, ptr @board, i64 75), i64 %11
  tail call void @llvm.memset.p0.i64(ptr align 1 %gep15, i8 46, i64 %4, i1 false), !tbaa !9
  %12 = mul nuw i64 %indvar, 15
  %gep16 = getelementptr i8, ptr getelementptr (i8, ptr @board, i64 90), i64 %12
  tail call void @llvm.memset.p0.i64(ptr align 2 %gep16, i8 46, i64 %4, i1 false), !tbaa !9
  %13 = mul nuw i64 %indvar, 15
  %gep17 = getelementptr i8, ptr getelementptr (i8, ptr @board, i64 105), i64 %13
  tail call void @llvm.memset.p0.i64(ptr align 1 %gep17, i8 46, i64 %4, i1 false), !tbaa !9
  %indvar.next.7 = add nuw nsw i64 %indvar, 8
  %niter.next.7 = add i64 %niter, 8
  %niter.ncmp.7 = icmp eq i64 %niter.next.7, %unroll_iter
  br i1 %niter.ncmp.7, label %._crit_edge9.loopexit.unr-lcssa, label %.preheader.us, !llvm.loop !10

._crit_edge9.loopexit.unr-lcssa:                  ; preds = %.preheader.us, %.preheader.us.preheader
  %indvar.unr = phi i64 [ 0, %.preheader.us.preheader ], [ %indvar.next.7, %.preheader.us ]
  %lcmp.mod.not = icmp eq i64 %xtraiter, 0
  br i1 %lcmp.mod.not, label %._crit_edge9, label %.preheader.us.epil

.preheader.us.epil:                               ; preds = %._crit_edge9.loopexit.unr-lcssa, %.preheader.us.epil
  %indvar.epil = phi i64 [ %indvar.next.epil, %.preheader.us.epil ], [ %indvar.unr, %._crit_edge9.loopexit.unr-lcssa ]
  %epil.iter = phi i64 [ %epil.iter.next, %.preheader.us.epil ], [ 0, %._crit_edge9.loopexit.unr-lcssa ]
  %14 = mul nuw nsw i64 %indvar.epil, 15
  %scevgep.epil = getelementptr i8, ptr @board, i64 %14
  tail call void @llvm.memset.p0.i64(ptr align 1 %scevgep.epil, i8 46, i64 %4, i1 false), !tbaa !9
  %indvar.next.epil = add nuw nsw i64 %indvar.epil, 1
  %epil.iter.next = add i64 %epil.iter, 1
  %epil.iter.cmp.not = icmp eq i64 %epil.iter.next, %xtraiter
  br i1 %epil.iter.cmp.not, label %._crit_edge9, label %.preheader.us.epil, !llvm.loop !12

._crit_edge9:                                     ; preds = %._crit_edge9.loopexit.unr-lcssa, %.preheader.us.epil, %0
  tail call void @_Z7solveNQi(i32 noundef 0)
  ret i32 0
}

; Function Attrs: nofree nounwind
declare noundef i32 @__isoc99_scanf(ptr nocapture noundef readonly, ...) local_unnamed_addr #2

; Function Attrs: nocallback nofree nounwind willreturn memory(argmem: write)
declare void @llvm.memset.p0.i64(ptr nocapture writeonly, i8, i64, i1 immarg) #3

attributes #0 = { 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 #1 = { mustprogress norecurse 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 = { 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 #3 = { nocallback nofree nounwind willreturn memory(argmem: write) }

!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 = !{!7, !7, i64 0}
!10 = distinct !{!10, !11}
!11 = !{!"llvm.loop.mustprogress"}
!12 = distinct !{!12, !13}
!13 = !{!"llvm.loop.unroll.disable"}


; Effective O3 passes: EarlyCSEPass,GVNPass,GlobalOptPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LICMPass,LoopIdiomRecognizePass,LoopRotatePass,LoopSimplifyCFGPass,LoopSimplifyPass,LoopUnrollPass,SROAPass,SimplifyCFGPass,TailCallElimPass