; LLVM IR from Algo-Phantoms/Algo-Tree :: Code/C++/Deletion of Alternate nodes in a linked list.ll (Z16alternate_deletev)

; 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 }

@head = external dso_local global ptr, 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: mustprogress nounwind uwtable
define dso_local void @_Z16alternate_deletev() #1 {
  %1 = alloca ptr, align 8
  %2 = alloca ptr, align 8
  %3 = load ptr, ptr @head, align 8, !tbaa !5
  %4 = icmp eq ptr %3, null
  br i1 %4, label %5, label %6

5:                                                ; preds = %0
  br label %37

6:                                                ; preds = %0
  call void @llvm.lifetime.start.p0(i64 8, ptr %1) #3
  %7 = load ptr, ptr @head, align 8, !tbaa !5
  store ptr %7, ptr %1, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %2) #3
  %8 = load ptr, ptr @head, align 8, !tbaa !5
  %9 = getelementptr inbounds %class.Node, ptr %8, i32 0, i32 1
  %10 = load ptr, ptr %9, align 8, !tbaa !9
  store ptr %10, ptr %2, align 8, !tbaa !5
  br label %11

11:                                               ; preds = %35, %6
  %12 = load ptr, ptr %2, align 8, !tbaa !5
  %13 = icmp ne ptr %12, null
  br i1 %13, label %14, label %17

14:                                               ; preds = %11
  %15 = load ptr, ptr %1, align 8, !tbaa !5
  %16 = icmp ne ptr %15, null
  br label %17

17:                                               ; preds = %14, %11
  %18 = phi i1 [ false, %11 ], [ %16, %14 ]
  br i1 %18, label %19, label %36

19:                                               ; preds = %17
  %20 = load ptr, ptr %2, align 8, !tbaa !5
  %21 = getelementptr inbounds %class.Node, ptr %20, i32 0, i32 1
  %22 = load ptr, ptr %21, align 8, !tbaa !9
  %23 = load ptr, ptr %1, align 8, !tbaa !5
  %24 = getelementptr inbounds %class.Node, ptr %23, i32 0, i32 1
  store ptr %22, ptr %24, align 8, !tbaa !9
  %25 = load ptr, ptr %2, align 8, !tbaa !5
  call void @free(ptr noundef %25) #3
  %26 = load ptr, ptr %1, align 8, !tbaa !5
  %27 = getelementptr inbounds %class.Node, ptr %26, i32 0, i32 1
  %28 = load ptr, ptr %27, align 8, !tbaa !9
  store ptr %28, ptr %1, align 8, !tbaa !5
  %29 = load ptr, ptr %1, align 8, !tbaa !5
  %30 = icmp ne ptr %29, null
  br i1 %30, label %31, label %35

31:                                               ; preds = %19
  %32 = load ptr, ptr %1, align 8, !tbaa !5
  %33 = getelementptr inbounds %class.Node, ptr %32, i32 0, i32 1
  %34 = load ptr, ptr %33, align 8, !tbaa !9
  store ptr %34, ptr %2, align 8, !tbaa !5
  br label %35

35:                                               ; preds = %31, %19
  br label %11, !llvm.loop !12

36:                                               ; preds = %17
  call void @llvm.lifetime.end.p0(i64 8, ptr %2) #3
  call void @llvm.lifetime.end.p0(i64 8, ptr %1) #3
  br label %37

37:                                               ; preds = %36, %5
  ret void
}

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

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 = { 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, !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"

@head = external dso_local local_unnamed_addr global ptr, align 8

; Function Attrs: mustprogress nounwind uwtable
define dso_local void @_Z16alternate_deletev() local_unnamed_addr #0 {
  %1 = load ptr, ptr @head, align 8, !tbaa !5
  %2 = icmp eq ptr %1, null
  br i1 %2, label %.loopexit, label %3

3:                                                ; preds = %0
  %4 = getelementptr inbounds i8, ptr %1, i64 8
  %5 = load ptr, ptr %4, align 8, !tbaa !9
  %.not13 = icmp eq ptr %5, null
  br i1 %.not13, label %.loopexit, label %.lr.ph

.lr.ph:                                           ; preds = %3, %10
  %.012 = phi ptr [ %12, %10 ], [ %5, %3 ]
  %.0811 = phi ptr [ %9, %10 ], [ %1, %3 ]
  %6 = getelementptr inbounds i8, ptr %.012, i64 8
  %7 = load ptr, ptr %6, align 8, !tbaa !9
  %8 = getelementptr inbounds i8, ptr %.0811, i64 8
  store ptr %7, ptr %8, align 8, !tbaa !9
  tail call void @free(ptr noundef nonnull %.012) #2
  %9 = load ptr, ptr %8, align 8, !tbaa !9
  %.not = icmp eq ptr %9, null
  br i1 %.not, label %.loopexit, label %10

10:                                               ; preds = %.lr.ph
  %11 = getelementptr inbounds i8, ptr %9, i64 8
  %12 = load ptr, ptr %11, align 8, !tbaa !9
  %.not15 = icmp eq ptr %12, null
  br i1 %.not15, label %.loopexit, label %.lr.ph, !llvm.loop !12

.loopexit:                                        ; preds = %.lr.ph, %10, %3, %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 = { 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 = { 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, !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: CorrelatedValuePropagationPass,EarlyCSEPass,GlobalOptPass,InferFunctionAttrsPass,InstCombinePass,JumpThreadingPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,ReassociatePass,SROAPass,SimplifyCFGPass,TailCallElimPass