; LLVM IR from JessonYue/LeetCodeLearning :: Array/xietao/第二周作业/字符串反转 (StringReverse)

; 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 @reverString(ptr noundef %0) #0 {
  %2 = alloca ptr, align 8
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  %5 = alloca i32, align 4
  %6 = alloca i8, align 1
  store ptr %0, ptr %2, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %3) #3
  store ptr null, ptr %3, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %4) #3
  store ptr null, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #3
  %7 = load ptr, ptr %2, align 8, !tbaa !5
  %8 = call i64 @strlen(ptr noundef %7) #4
  %9 = trunc i64 %8 to i32
  store i32 %9, ptr %5, align 4, !tbaa !9
  %10 = load ptr, ptr %2, align 8, !tbaa !5
  store ptr %10, ptr %3, align 8, !tbaa !5
  %11 = load ptr, ptr %2, align 8, !tbaa !5
  %12 = load i32, ptr %5, align 4, !tbaa !9
  %13 = sext i32 %12 to i64
  %14 = getelementptr inbounds i8, ptr %11, i64 %13
  %15 = getelementptr inbounds i8, ptr %14, i64 -1
  store ptr %15, ptr %4, align 8, !tbaa !5
  br label %16

16:                                               ; preds = %20, %1
  %17 = load ptr, ptr %3, align 8, !tbaa !5
  %18 = load ptr, ptr %4, align 8, !tbaa !5
  %19 = icmp ult ptr %17, %18
  br i1 %19, label %20, label %32

20:                                               ; preds = %16
  call void @llvm.lifetime.start.p0(i64 1, ptr %6) #3
  %21 = load ptr, ptr %3, align 8, !tbaa !5
  %22 = load i8, ptr %21, align 1, !tbaa !11
  store i8 %22, ptr %6, align 1, !tbaa !11
  %23 = load ptr, ptr %4, align 8, !tbaa !5
  %24 = load i8, ptr %23, align 1, !tbaa !11
  %25 = load ptr, ptr %3, align 8, !tbaa !5
  store i8 %24, ptr %25, align 1, !tbaa !11
  %26 = load i8, ptr %6, align 1, !tbaa !11
  %27 = load ptr, ptr %4, align 8, !tbaa !5
  store i8 %26, ptr %27, align 1, !tbaa !11
  %28 = load ptr, ptr %3, align 8, !tbaa !5
  %29 = getelementptr inbounds i8, ptr %28, i32 1
  store ptr %29, ptr %3, align 8, !tbaa !5
  %30 = load ptr, ptr %4, align 8, !tbaa !5
  %31 = getelementptr inbounds i8, ptr %30, i32 -1
  store ptr %31, ptr %4, align 8, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 1, ptr %6) #3
  br label %16, !llvm.loop !12

32:                                               ; preds = %16
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #3
  call void @llvm.lifetime.end.p0(i64 8, ptr %4) #3
  call void @llvm.lifetime.end.p0(i64 8, ptr %3) #3
  ret void
}

; 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: 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 }
attributes #4 = { 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 = !{!7, !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"

; Function Attrs: nofree nounwind memory(readwrite, inaccessiblemem: none) uwtable
define dso_local void @reverString(ptr noundef %0) local_unnamed_addr #0 {
  %2 = tail call i64 @strlen(ptr noundef nonnull dereferenceable(1) %0) #2
  %sext = shl i64 %2, 32
  %3 = ashr exact i64 %sext, 32
  %4 = getelementptr inbounds i8, ptr %0, i64 %3
  %.01213 = getelementptr inbounds i8, ptr %4, i64 -1
  %5 = icmp ugt ptr %.01213, %0
  br i1 %5, label %.lr.ph, label %._crit_edge

.lr.ph:                                           ; preds = %1, %.lr.ph
  %.01215 = phi ptr [ %.012, %.lr.ph ], [ %.01213, %1 ]
  %.014 = phi ptr [ %8, %.lr.ph ], [ %0, %1 ]
  %6 = load i8, ptr %.014, align 1, !tbaa !5
  %7 = load i8, ptr %.01215, align 1, !tbaa !5
  store i8 %7, ptr %.014, align 1, !tbaa !5
  store i8 %6, ptr %.01215, align 1, !tbaa !5
  %8 = getelementptr inbounds i8, ptr %.014, i64 1
  %.012 = getelementptr inbounds i8, ptr %.01215, i64 -1
  %9 = icmp ult ptr %8, %.012
  br i1 %9, label %.lr.ph, label %._crit_edge, !llvm.loop !8

._crit_edge:                                      ; preds = %.lr.ph, %1
  ret void
}

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

attributes #0 = { nofree nounwind memory(readwrite, inaccessiblemem: none) 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 = { 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 = !{!"omnipotent char", !7, i64 0}
!7 = !{!"Simple C/C++ TBAA"}
!8 = distinct !{!8, !9}
!9 = !{!"llvm.loop.mustprogress"}


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