; LLVM IR from TheAlgorithms/C-Plus-Plus :: backtracking (n_queens)

; 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.std::array" = type { [4 x %"struct.std::array.0"] }
%"struct.std::array.0" = type { [4 x i32] }

; Function Attrs: mustprogress norecurse uwtable
define dso_local noundef i32 @main() #0 {
  %1 = alloca i32, align 4
  %2 = alloca i32, align 4
  %3 = alloca %"struct.std::array", align 4
  %4 = alloca %"struct.std::array", align 8
  %5 = alloca i32, align 4
  store i32 0, ptr %1, align 4
  call void @llvm.lifetime.start.p0(i64 4, ptr %2) #5
  store i32 4, ptr %2, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 64, ptr %3) #5
  call void @llvm.memset.p0.i64(ptr align 4 %3, i8 0, i64 64, i1 false)
  call void @llvm.memcpy.p0.p0.i64(ptr align 4 %4, ptr align 4 %3, i64 64, i1 false), !tbaa.struct !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #5
  store i32 0, ptr %5, align 4, !tbaa !5
  call void @_ZN12backtracking8n_queens7solveNQILm4EEEvSt5arrayIS2_IiXT_EEXT_EERKi(ptr noundef byval(%"struct.std::array") align 8 %4, ptr noundef nonnull align 4 dereferenceable(4) %5)
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #5
  call void @llvm.lifetime.end.p0(i64 64, ptr %3) #5
  call void @llvm.lifetime.end.p0(i64 4, ptr %2) #5
  ret i32 0
}

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

; Function Attrs: nocallback nofree nounwind willreturn memory(argmem: write)
declare void @llvm.memset.p0.i64(ptr nocapture writeonly, i8, i64, i1 immarg) #2

; Function Attrs: mustprogress uwtable
declare dso_local void @_ZN12backtracking8n_queens7solveNQILm4EEEvSt5arrayIS2_IiXT_EEXT_EERKi(ptr noundef byval(%"struct.std::array") align 8, ptr noundef nonnull align 4 dereferenceable(4)) #3

; Function Attrs: nocallback nofree nounwind willreturn memory(argmem: readwrite)
declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg) #4

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

attributes #0 = { 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 #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #2 = { nocallback nofree nounwind willreturn memory(argmem: write) }
attributes #3 = { 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 #4 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
attributes #5 = { 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 = !{i64 0, i64 64, !10}
!10 = !{!7, !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"

%"struct.std::array" = type { [4 x %"struct.std::array.0"] }
%"struct.std::array.0" = type { [4 x i32] }

; Function Attrs: mustprogress norecurse uwtable
define dso_local noundef i32 @main() local_unnamed_addr #0 {
  %1 = alloca %"struct.std::array", align 8
  %2 = alloca i32, align 4
  call void @llvm.memset.p0.i64(ptr noundef nonnull align 8 dereferenceable(64) %1, i8 0, i64 64, i1 false)
  call void @llvm.lifetime.start.p0(i64 4, ptr nonnull %2) #4
  store i32 0, ptr %2, align 4, !tbaa !5
  call void @_ZN12backtracking8n_queens7solveNQILm4EEEvSt5arrayIS2_IiXT_EEXT_EERKi(ptr noundef nonnull byval(%"struct.std::array") align 8 %1, ptr noundef nonnull align 4 dereferenceable(4) %2)
  call void @llvm.lifetime.end.p0(i64 4, ptr nonnull %2) #4
  ret i32 0
}

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

; Function Attrs: mustprogress nocallback nofree nounwind willreturn memory(argmem: write)
declare void @llvm.memset.p0.i64(ptr nocapture writeonly, i8, i64, i1 immarg) #2

; Function Attrs: mustprogress uwtable
declare dso_local void @_ZN12backtracking8n_queens7solveNQILm4EEEvSt5arrayIS2_IiXT_EEXT_EERKi(ptr noundef byval(%"struct.std::array") align 8, ptr noundef nonnull align 4 dereferenceable(4)) local_unnamed_addr #3

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

attributes #0 = { 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 #1 = { mustprogress nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #2 = { mustprogress nocallback nofree nounwind willreturn memory(argmem: write) }
attributes #3 = { 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 #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"}


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