; LLVM IR from AlgoGenesis/C :: Backtracking Algorithms/Dancing Links (DLX) (program)

; 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.Column = type { %struct.Node, i32, [20 x i8] }
%struct.Node = type { ptr, ptr, ptr, ptr, ptr }

@root = external hidden global %struct.Column, align 8

; 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: nounwind uwtable
define dso_local void @free_dlx() #1 {
  %1 = alloca ptr, align 8
  %2 = alloca ptr, align 8
  %3 = alloca ptr, align 8
  call void @llvm.lifetime.start.p0(i64 8, ptr %1) #3
  %4 = load ptr, ptr getelementptr inbounds (%struct.Node, ptr @root, i32 0, i32 1), align 8, !tbaa !5
  store ptr %4, ptr %1, align 8, !tbaa !12
  br label %5

5:                                                ; preds = %8, %0
  %6 = load ptr, ptr %1, align 8, !tbaa !12
  %7 = icmp ne ptr %6, @root
  br i1 %7, label %8, label %17

8:                                                ; preds = %5
  call void @llvm.lifetime.start.p0(i64 8, ptr %2) #3
  %9 = load ptr, ptr %1, align 8, !tbaa !12
  %10 = getelementptr inbounds %struct.Node, ptr %9, i32 0, i32 4
  %11 = load ptr, ptr %10, align 8, !tbaa !13
  store ptr %11, ptr %2, align 8, !tbaa !12
  call void @llvm.lifetime.start.p0(i64 8, ptr %3) #3
  %12 = load ptr, ptr %1, align 8, !tbaa !12
  %13 = getelementptr inbounds %struct.Node, ptr %12, i32 0, i32 1
  %14 = load ptr, ptr %13, align 8, !tbaa !14
  store ptr %14, ptr %3, align 8, !tbaa !12
  %15 = load ptr, ptr %2, align 8, !tbaa !12
  call void @free(ptr noundef %15) #3
  %16 = load ptr, ptr %3, align 8, !tbaa !12
  store ptr %16, ptr %1, align 8, !tbaa !12
  call void @llvm.lifetime.end.p0(i64 8, ptr %3) #3
  call void @llvm.lifetime.end.p0(i64 8, ptr %2) #3
  br label %5, !llvm.loop !15

17:                                               ; preds = %5
  call void @llvm.lifetime.end.p0(i64 8, ptr %1) #3
  ret void
}

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

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { 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 = { 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, !8, i64 8}
!6 = !{!"Column", !7, i64 0, !11, i64 40, !9, i64 44}
!7 = !{!"Node", !8, i64 0, !8, i64 8, !8, i64 16, !8, i64 24, !8, i64 32}
!8 = !{!"any pointer", !9, i64 0}
!9 = !{!"omnipotent char", !10, i64 0}
!10 = !{!"Simple C/C++ TBAA"}
!11 = !{!"int", !9, i64 0}
!12 = !{!8, !8, i64 0}
!13 = !{!7, !8, i64 32}
!14 = !{!7, !8, i64 8}
!15 = distinct !{!15, !16}
!16 = !{!"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"

%struct.Column = type { %struct.Node, i32, [20 x i8] }
%struct.Node = type { ptr, ptr, ptr, ptr, ptr }

@root = external hidden global %struct.Column, align 8

; Function Attrs: nounwind uwtable
define dso_local void @free_dlx() local_unnamed_addr #0 {
  %1 = load ptr, ptr getelementptr inbounds (i8, ptr @root, i64 8), align 8, !tbaa !5
  %.not5 = icmp eq ptr %1, @root
  br i1 %.not5, label %._crit_edge, label %.lr.ph

.lr.ph:                                           ; preds = %0, %.lr.ph
  %.06 = phi ptr [ %5, %.lr.ph ], [ %1, %0 ]
  %2 = getelementptr inbounds i8, ptr %.06, i64 32
  %3 = load ptr, ptr %2, align 8, !tbaa !12
  %4 = getelementptr inbounds i8, ptr %.06, i64 8
  %5 = load ptr, ptr %4, align 8, !tbaa !13
  tail call void @free(ptr noundef %3) #2
  %.not = icmp eq ptr %5, @root
  br i1 %.not, label %._crit_edge, label %.lr.ph, !llvm.loop !14

._crit_edge:                                      ; preds = %.lr.ph, %0
  ret void
}

; 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 = { 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 = { 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, !8, i64 8}
!6 = !{!"Column", !7, i64 0, !11, i64 40, !9, i64 44}
!7 = !{!"Node", !8, i64 0, !8, i64 8, !8, i64 16, !8, i64 24, !8, i64 32}
!8 = !{!"any pointer", !9, i64 0}
!9 = !{!"omnipotent char", !10, i64 0}
!10 = !{!"Simple C/C++ TBAA"}
!11 = !{!"int", !9, i64 0}
!12 = !{!7, !8, i64 32}
!13 = !{!7, !8, i64 8}
!14 = distinct !{!14, !15}
!15 = !{!"llvm.loop.mustprogress"}


; Effective O3 passes: GlobalOptPass,InferFunctionAttrsPass,InstCombinePass,JumpThreadingPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,SROAPass,SimplifyCFGPass,TailCallElimPass