; LLVM IR from ImChong/Practice_LeetCode_C :: F02_Programming_Topics/F01_Data_Structure/04_String/01_ReverseString (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 void @reverseString(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) #3
  store i32 0, ptr %5, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %6) #3
  %7 = load i32, ptr %4, align 4, !tbaa !9
  %8 = sub nsw i32 %7, 1
  store i32 %8, ptr %6, align 4, !tbaa !9
  br label %9

9:                                                ; preds = %13, %2
  %10 = load i32, ptr %5, align 4, !tbaa !9
  %11 = load i32, ptr %6, align 4, !tbaa !9
  %12 = icmp slt i32 %10, %11
  br i1 %12, label %13, label %27

13:                                               ; preds = %9
  %14 = load ptr, ptr %3, align 8, !tbaa !5
  %15 = load i32, ptr %5, align 4, !tbaa !9
  %16 = sext i32 %15 to i64
  %17 = getelementptr inbounds i8, ptr %14, i64 %16
  %18 = load ptr, ptr %3, align 8, !tbaa !5
  %19 = load i32, ptr %6, align 4, !tbaa !9
  %20 = sext i32 %19 to i64
  %21 = getelementptr inbounds i8, ptr %18, i64 %20
  %22 = call i32 @Char_Swap(ptr noundef %17, ptr noundef %21)
  %23 = load i32, ptr %5, align 4, !tbaa !9
  %24 = add nsw i32 %23, 1
  store i32 %24, ptr %5, align 4, !tbaa !9
  %25 = load i32, ptr %6, align 4, !tbaa !9
  %26 = add nsw i32 %25, -1
  store i32 %26, ptr %6, align 4, !tbaa !9
  br label %9, !llvm.loop !11

27:                                               ; preds = %9
  call void @llvm.lifetime.end.p0(i64 4, ptr %6) #3
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #3
  ret void
}

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

declare i32 @Char_Swap(ptr noundef, ptr noundef) #2

; 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 = { "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/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 void @reverseString(ptr noundef %0, i32 noundef %1) local_unnamed_addr #0 {
  %3 = icmp sgt i32 %1, 1
  br i1 %3, label %.lr.ph.preheader, label %._crit_edge

.lr.ph.preheader:                                 ; preds = %2
  %4 = zext nneg i32 %1 to i64
  %5 = add nsw i64 %4, -1
  br label %.lr.ph

.lr.ph:                                           ; preds = %.lr.ph.preheader, %.lr.ph
  %indvars.iv12 = phi i64 [ 0, %.lr.ph.preheader ], [ %indvars.iv.next13, %.lr.ph ]
  %indvars.iv = phi i64 [ %5, %.lr.ph.preheader ], [ %indvars.iv.next, %.lr.ph ]
  %6 = getelementptr inbounds i8, ptr %0, i64 %indvars.iv12
  %7 = getelementptr inbounds i8, ptr %0, i64 %indvars.iv
  %8 = tail call i32 @Char_Swap(ptr noundef %6, ptr noundef %7) #2
  %indvars.iv.next13 = add nuw nsw i64 %indvars.iv12, 1
  %indvars.iv.next = add nsw i64 %indvars.iv, -1
  %9 = icmp slt i64 %indvars.iv.next13, %indvars.iv.next
  br i1 %9, label %.lr.ph, label %._crit_edge, !llvm.loop !5

._crit_edge:                                      ; preds = %.lr.ph, %2
  ret void
}

declare i32 @Char_Swap(ptr noundef, ptr noundef) local_unnamed_addr #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 = { "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 = distinct !{!5, !6}
!6 = !{!"llvm.loop.mustprogress"}


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