; LLVM IR from freddiev4/dailyprogrammerchallenges :: Intermediate Challenges/Challenge 0004 Intermediate/solutions (solution)

; 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.Explist = type { ptr, ptr }

@.str.35 = external hidden unnamed_addr constant [12 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: nounwind allocsize(0)
declare noalias ptr @malloc(i64 noundef) #1

; Function Attrs: noreturn nounwind
declare void @exit(i32 noundef) #2

declare void @perror(ptr noundef) #3

; Function Attrs: nounwind uwtable
define dso_local ptr @Explist_new() #4 {
  %1 = alloca ptr, align 8
  call void @llvm.lifetime.start.p0(i64 8, ptr %1) #5
  %2 = call noalias ptr @malloc(i64 noundef 16) #6
  store ptr %2, ptr %1, align 8, !tbaa !5
  %3 = load ptr, ptr %1, align 8, !tbaa !5
  %4 = icmp eq ptr %3, null
  br i1 %4, label %5, label %6

5:                                                ; preds = %0
  call void @perror(ptr noundef @.str.35)
  call void @exit(i32 noundef 1) #7
  unreachable

6:                                                ; preds = %0
  %7 = load ptr, ptr %1, align 8, !tbaa !5
  %8 = getelementptr inbounds %struct.Explist, ptr %7, i32 0, i32 0
  store ptr null, ptr %8, align 8, !tbaa !9
  %9 = load ptr, ptr %1, align 8, !tbaa !5
  %10 = getelementptr inbounds %struct.Explist, ptr %9, i32 0, i32 1
  store ptr null, ptr %10, align 8, !tbaa !11
  %11 = load ptr, ptr %1, align 8, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 8, ptr %1) #5
  ret ptr %11
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { nounwind allocsize(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 = { noreturn 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 = { "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 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 #5 = { nounwind }
attributes #6 = { nounwind allocsize(0) }
attributes #7 = { noreturn 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/C++ TBAA"}
!9 = !{!10, !6, i64 0}
!10 = !{!"Explist", !6, i64 0, !6, i64 8}
!11 = !{!10, !6, i64 8}


; 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"

@.str.35 = external hidden unnamed_addr constant [12 x i8], align 1

; Function Attrs: noreturn nounwind
declare void @exit(i32 noundef) local_unnamed_addr #0

; Function Attrs: nofree nounwind
declare void @perror(ptr nocapture noundef readonly) local_unnamed_addr #1

; Function Attrs: nounwind uwtable
define dso_local noalias noundef ptr @Explist_new() local_unnamed_addr #2 {
  %calloc = tail call dereferenceable_or_null(16) ptr @calloc(i64 1, i64 16)
  %1 = icmp eq ptr %calloc, null
  br i1 %1, label %2, label %3

2:                                                ; preds = %0
  tail call void @perror(ptr noundef nonnull @.str.35) #4
  tail call void @exit(i32 noundef 1) #5
  unreachable

3:                                                ; preds = %0
  ret ptr %calloc
}

; Function Attrs: nofree nounwind willreturn allockind("alloc,zeroed") allocsize(0,1) memory(inaccessiblemem: readwrite)
declare noalias noundef ptr @calloc(i64 noundef, i64 noundef) local_unnamed_addr #3

attributes #0 = { noreturn 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 #1 = { 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 #2 = { 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 = { nofree nounwind willreturn allockind("alloc,zeroed") allocsize(0,1) memory(inaccessiblemem: readwrite) "alloc-family"="malloc" }
attributes #4 = { cold }
attributes #5 = { noreturn 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)"}


; Effective O3 passes: DSEPass,EarlyCSEPass,GlobalOptPass,InferFunctionAttrsPass,InstCombinePass,MemCpyOptPass,PostOrderFunctionAttrsPass,SROAPass,TailCallElimPass