; LLVM IR from AllenDowney/ExercisesInC :: exercises/ex04 (bigbadint)

; 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"

; Function Attrs: nounwind uwtable
define dso_local ptr @reverse_string(ptr noundef %0) #0 {
  %2 = alloca ptr, align 8
  %3 = alloca i32, align 4
  %4 = alloca ptr, align 8
  %5 = alloca ptr, align 8
  %6 = alloca ptr, align 8
  store ptr %0, ptr %2, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #4
  %7 = load ptr, ptr %2, align 8, !tbaa !5
  %8 = call i64 @strlen(ptr noundef %7) #5
  %9 = trunc i64 %8 to i32
  store i32 %9, ptr %3, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #4
  %10 = load i32, ptr %3, align 4, !tbaa !9
  %11 = add nsw i32 %10, 1
  %12 = sext i32 %11 to i64
  %13 = call noalias ptr @malloc(i64 noundef %12) #6
  store ptr %13, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #4
  %14 = load ptr, ptr %4, align 8, !tbaa !5
  store ptr %14, ptr %5, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %6) #4
  %15 = load ptr, ptr %2, align 8, !tbaa !5
  %16 = load i32, ptr %3, align 4, !tbaa !9
  %17 = sext i32 %16 to i64
  %18 = getelementptr inbounds i8, ptr %15, i64 %17
  %19 = getelementptr inbounds i8, ptr %18, i64 -1
  store ptr %19, ptr %6, align 8, !tbaa !5
  br label %20

20:                                               ; preds = %33, %1
  br label %21

21:                                               ; preds = %20
  %22 = load ptr, ptr %6, align 8, !tbaa !5
  %23 = load i8, ptr %22, align 1, !tbaa !11
  %24 = load ptr, ptr %5, align 8, !tbaa !5
  store i8 %23, ptr %24, align 1, !tbaa !11
  %25 = load ptr, ptr %5, align 8, !tbaa !5
  %26 = getelementptr inbounds i8, ptr %25, i32 1
  store ptr %26, ptr %5, align 8, !tbaa !5
  %27 = load ptr, ptr %6, align 8, !tbaa !5
  %28 = getelementptr inbounds i8, ptr %27, i32 -1
  store ptr %28, ptr %6, align 8, !tbaa !5
  %29 = load ptr, ptr %6, align 8, !tbaa !5
  %30 = load ptr, ptr %2, align 8, !tbaa !5
  %31 = icmp ult ptr %29, %30
  br i1 %31, label %32, label %33

32:                                               ; preds = %21
  br label %34

33:                                               ; preds = %21
  br label %20

34:                                               ; preds = %32
  %35 = load ptr, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 8, ptr %6) #4
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #4
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #4
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #4
  ret ptr %35
}

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

; Function Attrs: nounwind willreturn memory(read)
declare i64 @strlen(ptr noundef) #2

; Function Attrs: nounwind allocsize(0)
declare noalias ptr @malloc(i64 noundef) #3

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #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 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #2 = { nounwind willreturn memory(read) "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 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 #4 = { nounwind }
attributes #5 = { nounwind willreturn memory(read) }
attributes #6 = { nounwind allocsize(0) }

!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, !10, i64 0}
!10 = !{!"int", !7, i64 0}
!11 = !{!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"

; Function Attrs: nofree nounwind uwtable
define dso_local noalias noundef ptr @reverse_string(ptr noundef readonly %0) local_unnamed_addr #0 {
  %2 = tail call i64 @strlen(ptr noundef nonnull dereferenceable(1) %0) #3
  %3 = shl i64 %2, 32
  %sext = add i64 %3, 4294967296
  %4 = ashr exact i64 %sext, 32
  %5 = tail call noalias ptr @malloc(i64 noundef %4) #4
  %6 = ashr exact i64 %3, 32
  %7 = getelementptr inbounds i8, ptr %0, i64 %6
  %8 = getelementptr inbounds i8, ptr %7, i64 -1
  br label %9

9:                                                ; preds = %9, %1
  %.011 = phi ptr [ %5, %1 ], [ %11, %9 ]
  %.0 = phi ptr [ %8, %1 ], [ %12, %9 ]
  %10 = load i8, ptr %.0, align 1, !tbaa !5
  store i8 %10, ptr %.011, align 1, !tbaa !5
  %11 = getelementptr inbounds i8, ptr %.011, i64 1
  %12 = getelementptr inbounds i8, ptr %.0, i64 -1
  %13 = icmp ult ptr %12, %0
  br i1 %13, label %14, label %9

14:                                               ; preds = %9
  ret ptr %5
}

; Function Attrs: mustprogress nofree nounwind willreturn memory(argmem: read)
declare i64 @strlen(ptr nocapture noundef) local_unnamed_addr #1

; Function Attrs: mustprogress nofree nounwind willreturn allockind("alloc,uninitialized") allocsize(0) memory(inaccessiblemem: readwrite)
declare noalias noundef ptr @malloc(i64 noundef) local_unnamed_addr #2

attributes #0 = { nofree 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 nofree nounwind willreturn memory(argmem: read) "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 = { mustprogress nofree nounwind willreturn allockind("alloc,uninitialized") allocsize(0) memory(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 #3 = { nounwind willreturn memory(read) }
attributes #4 = { nounwind allocsize(0) }

!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 = !{!"omnipotent char", !7, i64 0}
!7 = !{!"Simple C/C++ TBAA"}


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