; LLVM IR from ImChong/Practice_LeetCode_C :: F02_Programming_Topics/F01_Data_Structure/04_String/02_ReverseStr (main)

; 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 @reverseStr(ptr noundef %0, i32 noundef %1) #0 {
  %3 = alloca ptr, align 8
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  %6 = alloca i32, align 4
  store ptr %0, ptr %3, align 8, !tbaa !5
  store i32 %1, ptr %4, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #4
  %7 = load ptr, ptr %3, align 8, !tbaa !5
  %8 = call i64 @strlen(ptr noundef %7) #5
  %9 = trunc i64 %8 to i32
  store i32 %9, ptr %5, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %6) #4
  store i32 0, ptr %6, align 4, !tbaa !9
  br label %10

10:                                               ; preds = %23, %2
  %11 = load i32, ptr %6, align 4, !tbaa !9
  %12 = load i32, ptr %5, align 4, !tbaa !9
  %13 = icmp slt i32 %11, %12
  br i1 %13, label %15, label %14

14:                                               ; preds = %10
  call void @llvm.lifetime.end.p0(i64 4, ptr %6) #4
  br label %28

15:                                               ; preds = %10
  %16 = load ptr, ptr %3, align 8, !tbaa !5
  %17 = load i32, ptr %6, align 4, !tbaa !9
  %18 = load i32, ptr %6, align 4, !tbaa !9
  %19 = load i32, ptr %4, align 4, !tbaa !9
  %20 = add nsw i32 %18, %19
  %21 = sub nsw i32 %20, 1
  %22 = call i32 @String_Reverse(ptr noundef %16, i32 noundef %17, i32 noundef %21)
  br label %23

23:                                               ; preds = %15
  %24 = load i32, ptr %4, align 4, !tbaa !9
  %25 = mul nsw i32 2, %24
  %26 = load i32, ptr %6, align 4, !tbaa !9
  %27 = add nsw i32 %26, %25
  store i32 %27, ptr %6, align 4, !tbaa !9
  br label %10, !llvm.loop !11

28:                                               ; preds = %14
  %29 = load ptr, ptr %3, align 8, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #4
  ret ptr %29
}

; 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

declare i32 @String_Reverse(ptr noundef, i32 noundef, i32 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 = { "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) }

!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 = distinct !{!11, !12}
!12 = !{!"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: nounwind uwtable
define dso_local noundef ptr @reverseStr(ptr noundef returned %0, i32 noundef %1) local_unnamed_addr #0 {
  %3 = tail call i64 @strlen(ptr noundef nonnull dereferenceable(1) %0) #3
  %4 = trunc i64 %3 to i32
  %5 = icmp sgt i32 %4, 0
  br i1 %5, label %.lr.ph, label %._crit_edge

.lr.ph:                                           ; preds = %2
  %6 = add i32 %1, -1
  %7 = shl nsw i32 %1, 1
  br label %8

._crit_edge:                                      ; preds = %8, %2
  ret ptr %0

8:                                                ; preds = %.lr.ph, %8
  %.09 = phi i32 [ 0, %.lr.ph ], [ %11, %8 ]
  %9 = add i32 %6, %.09
  %10 = tail call i32 @String_Reverse(ptr noundef %0, i32 noundef %.09, i32 noundef %9) #4
  %11 = add nsw i32 %.09, %7
  %12 = icmp slt i32 %11, %4
  br i1 %12, label %8, label %._crit_edge, !llvm.loop !5
}

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

declare i32 @String_Reverse(ptr noundef, i32 noundef, i32 noundef) local_unnamed_addr #2

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 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 = { "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 }

!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 = distinct !{!5, !6}
!6 = !{!"llvm.loop.mustprogress"}


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