; LLVM IR from devparthgarg/Data-Structures-and-Algorithms :: 11. Linked List/37 Pairwise Node Swap of LL (37 Pairwise Node Swap of LL)

; 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"

%class.Node = type { i32, ptr }

; Function Attrs: mustprogress nounwind uwtable
define dso_local noundef ptr @_Z8pairSwapRP4Node(ptr noundef nonnull align 8 dereferenceable(8) %0) #0 {
  %2 = alloca ptr, align 8
  %3 = alloca ptr, align 8
  store ptr %0, ptr %2, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %3) #3
  %4 = load ptr, ptr %2, align 8, !tbaa !5
  %5 = load ptr, ptr %4, align 8, !tbaa !5
  store ptr %5, ptr %3, align 8, !tbaa !5
  br label %6

6:                                                ; preds = %16, %1
  %7 = load ptr, ptr %3, align 8, !tbaa !5
  %8 = icmp ne ptr %7, null
  br i1 %8, label %9, label %14

9:                                                ; preds = %6
  %10 = load ptr, ptr %3, align 8, !tbaa !5
  %11 = getelementptr inbounds %class.Node, ptr %10, i32 0, i32 1
  %12 = load ptr, ptr %11, align 8, !tbaa !9
  %13 = icmp ne ptr %12, null
  br label %14

14:                                               ; preds = %9, %6
  %15 = phi i1 [ false, %6 ], [ %13, %9 ]
  br i1 %15, label %16, label %28

16:                                               ; preds = %14
  %17 = load ptr, ptr %3, align 8, !tbaa !5
  %18 = getelementptr inbounds %class.Node, ptr %17, i32 0, i32 0
  %19 = load ptr, ptr %3, align 8, !tbaa !5
  %20 = getelementptr inbounds %class.Node, ptr %19, i32 0, i32 1
  %21 = load ptr, ptr %20, align 8, !tbaa !9
  %22 = getelementptr inbounds %class.Node, ptr %21, i32 0, i32 0
  call void @_ZSt4swapIiENSt9enable_ifIXsr6__and_ISt6__not_ISt15__is_tuple_likeIT_EESt21is_move_constructibleIS3_ESt18is_move_assignableIS3_EEE5valueEvE4typeERS3_SC_(ptr noundef nonnull align 4 dereferenceable(4) %18, ptr noundef nonnull align 4 dereferenceable(4) %22) #3
  %23 = load ptr, ptr %3, align 8, !tbaa !5
  %24 = getelementptr inbounds %class.Node, ptr %23, i32 0, i32 1
  %25 = load ptr, ptr %24, align 8, !tbaa !9
  %26 = getelementptr inbounds %class.Node, ptr %25, i32 0, i32 1
  %27 = load ptr, ptr %26, align 8, !tbaa !9
  store ptr %27, ptr %3, align 8, !tbaa !5
  br label %6, !llvm.loop !12

28:                                               ; preds = %14
  %29 = load ptr, ptr %2, align 8, !tbaa !5
  %30 = load ptr, ptr %29, align 8, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 8, ptr %3) #3
  ret ptr %30
}

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

; Function Attrs: inlinehint mustprogress nounwind uwtable
declare dso_local void @_ZSt4swapIiENSt9enable_ifIXsr6__and_ISt6__not_ISt15__is_tuple_likeIT_EESt21is_move_constructibleIS3_ESt18is_move_assignableIS3_EEE5valueEvE4typeERS3_SC_(ptr noundef nonnull align 4 dereferenceable(4), ptr noundef nonnull align 4 dereferenceable(4)) #2

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #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" }
attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #2 = { inlinehint 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 #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 = !{!"any pointer", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = !{!10, !6, i64 8}
!10 = !{!"_ZTS4Node", !11, i64 0, !6, i64 8}
!11 = !{!"int", !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"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"

; Function Attrs: mustprogress nounwind uwtable
define dso_local noundef ptr @_Z8pairSwapRP4Node(ptr nocapture noundef nonnull readonly align 8 dereferenceable(8) %0) local_unnamed_addr #0 {
  %.09 = load ptr, ptr %0, align 8, !tbaa !5
  %.not10 = icmp eq ptr %.09, null
  br i1 %.not10, label %.critedge, label %.lr.ph

.lr.ph:                                           ; preds = %1, %4
  %.011 = phi ptr [ %.0, %4 ], [ %.09, %1 ]
  %2 = getelementptr inbounds i8, ptr %.011, i64 8
  %3 = load ptr, ptr %2, align 8, !tbaa !9
  %.not8 = icmp eq ptr %3, null
  br i1 %.not8, label %.critedge.loopexit, label %4

4:                                                ; preds = %.lr.ph
  tail call void @_ZSt4swapIiENSt9enable_ifIXsr6__and_ISt6__not_ISt15__is_tuple_likeIT_EESt21is_move_constructibleIS3_ESt18is_move_assignableIS3_EEE5valueEvE4typeERS3_SC_(ptr noundef nonnull align 4 dereferenceable(4) %.011, ptr noundef nonnull align 4 dereferenceable(4) %3) #2
  %5 = load ptr, ptr %2, align 8, !tbaa !9
  %6 = getelementptr inbounds i8, ptr %5, i64 8
  %.0 = load ptr, ptr %6, align 8, !tbaa !5
  %.not = icmp eq ptr %.0, null
  br i1 %.not, label %.critedge.loopexit, label %.lr.ph, !llvm.loop !12

.critedge.loopexit:                               ; preds = %4, %.lr.ph
  %.pre = load ptr, ptr %0, align 8, !tbaa !5
  br label %.critedge

.critedge:                                        ; preds = %.critedge.loopexit, %1
  %7 = phi ptr [ %.pre, %.critedge.loopexit ], [ null, %1 ]
  ret ptr %7
}

; Function Attrs: inlinehint mustprogress nounwind uwtable
declare dso_local void @_ZSt4swapIiENSt9enable_ifIXsr6__and_ISt6__not_ISt15__is_tuple_likeIT_EESt21is_move_constructibleIS3_ESt18is_move_assignableIS3_EEE5valueEvE4typeERS3_SC_(ptr noundef nonnull align 4 dereferenceable(4), ptr noundef nonnull align 4 dereferenceable(4)) local_unnamed_addr #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" }
attributes #1 = { inlinehint 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 = { 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 = !{!"any pointer", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = !{!10, !6, i64 8}
!10 = !{!"_ZTS4Node", !11, i64 0, !6, i64 8}
!11 = !{!"int", !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"llvm.loop.mustprogress"}


; Effective O3 passes: EarlyCSEPass,GVNPass,GlobalOptPass,InferFunctionAttrsPass,InstCombinePass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass