; LLVM IR from JessonYue/LeetCodeLearning :: Array/zhangjunwei/7.6-7.12/7.6-7.12.ll (Z15rever_characterPKci)

; 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: 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: mustprogress nounwind uwtable
define dso_local noundef ptr @_Z15rever_characterPKci(ptr noundef %0, i32 noundef %1) #1 {
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  %5 = alloca i32, align 4
  %6 = alloca ptr, align 8
  %7 = alloca ptr, align 8
  %8 = alloca i32, align 4
  %9 = alloca i32, align 4
  store ptr %0, ptr %4, align 8, !tbaa !5
  store i32 %1, ptr %5, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 8, ptr %6) #3
  %10 = load ptr, ptr %4, align 8, !tbaa !5
  store ptr %10, ptr %6, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %7) #3
  %11 = load i32, ptr %5, align 4, !tbaa !9
  %12 = sext i32 %11 to i64
  %13 = mul i64 1, %12
  %14 = call noalias ptr @malloc(i64 noundef %13) #4
  store ptr %14, ptr %7, align 8, !tbaa !5
  %15 = load ptr, ptr %7, align 8, !tbaa !5
  %16 = icmp eq ptr %15, null
  br i1 %16, label %17, label %18

17:                                               ; preds = %2
  store ptr null, ptr %3, align 8
  store i32 1, ptr %8, align 4
  br label %44

18:                                               ; preds = %2
  call void @llvm.lifetime.start.p0(i64 4, ptr %9) #3
  store i32 0, ptr %9, align 4, !tbaa !9
  br label %19

19:                                               ; preds = %39, %18
  %20 = load i32, ptr %9, align 4, !tbaa !9
  %21 = load i32, ptr %5, align 4, !tbaa !9
  %22 = icmp slt i32 %20, %21
  br i1 %22, label %24, label %23

23:                                               ; preds = %19
  store i32 2, ptr %8, align 4
  call void @llvm.lifetime.end.p0(i64 4, ptr %9) #3
  br label %42

24:                                               ; preds = %19
  %25 = load ptr, ptr %6, align 8, !tbaa !5
  %26 = load i32, ptr %5, align 4, !tbaa !9
  %27 = sext i32 %26 to i64
  %28 = getelementptr inbounds i8, ptr %25, i64 %27
  %29 = load i32, ptr %9, align 4, !tbaa !9
  %30 = sext i32 %29 to i64
  %31 = sub i64 0, %30
  %32 = getelementptr inbounds i8, ptr %28, i64 %31
  %33 = getelementptr inbounds i8, ptr %32, i64 -1
  %34 = load i8, ptr %33, align 1, !tbaa !11
  %35 = load ptr, ptr %7, align 8, !tbaa !5
  %36 = load i32, ptr %9, align 4, !tbaa !9
  %37 = sext i32 %36 to i64
  %38 = getelementptr inbounds i8, ptr %35, i64 %37
  store i8 %34, ptr %38, align 1, !tbaa !11
  br label %39

39:                                               ; preds = %24
  %40 = load i32, ptr %9, align 4, !tbaa !9
  %41 = add nsw i32 %40, 1
  store i32 %41, ptr %9, align 4, !tbaa !9
  br label %19, !llvm.loop !12

42:                                               ; preds = %23
  %43 = load ptr, ptr %7, align 8, !tbaa !5
  store ptr %43, ptr %3, align 8
  store i32 1, ptr %8, align 4
  br label %44

44:                                               ; preds = %42, %17
  call void @llvm.lifetime.end.p0(i64 8, ptr %7) #3
  call void @llvm.lifetime.end.p0(i64 8, ptr %6) #3
  %45 = load ptr, ptr %3, align 8
  ret ptr %45
}

; Function Attrs: nounwind allocsize(0)
declare noalias ptr @malloc(i64 noundef) #2

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { mustprogress 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 #2 = { 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 #3 = { nounwind }
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 = !{!"any pointer", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple 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: mustprogress nofree nounwind memory(write, argmem: read, inaccessiblemem: readwrite) uwtable
define dso_local noalias noundef ptr @_Z15rever_characterPKci(ptr nocapture noundef readonly %0, i32 noundef %1) local_unnamed_addr #0 {
  %3 = sext i32 %1 to i64
  %4 = tail call noalias ptr @malloc(i64 noundef %3) #2
  %5 = icmp ne ptr %4, null
  %6 = icmp sgt i32 %1, 0
  %or.cond = and i1 %5, %6
  br i1 %or.cond, label %iter.check, label %.loopexit

iter.check:                                       ; preds = %2
  %7 = getelementptr inbounds i8, ptr %0, i64 %3
  %invariant.gep = getelementptr i8, ptr %7, i64 -1
  %wide.trip.count = zext nneg i32 %1 to i64
  %min.iters.check = icmp ult i32 %1, 8
  br i1 %min.iters.check, label %vec.epilog.scalar.ph.preheader, label %vector.main.loop.iter.check

vector.main.loop.iter.check:                      ; preds = %iter.check
  %min.iters.check16 = icmp ult i32 %1, 32
  br i1 %min.iters.check16, label %vec.epilog.ph, label %vector.ph

vector.ph:                                        ; preds = %vector.main.loop.iter.check
  %n.vec = and i64 %wide.trip.count, 2147483616
  br label %vector.body

vector.body:                                      ; preds = %vector.body, %vector.ph
  %index = phi i64 [ 0, %vector.ph ], [ %index.next, %vector.body ]
  %8 = sub nsw i64 0, %index
  %9 = getelementptr i8, ptr %invariant.gep, i64 %8
  %10 = getelementptr i8, ptr %9, i64 -15
  %11 = getelementptr i8, ptr %9, i64 -31
  %wide.load = load <16 x i8>, ptr %10, align 1, !tbaa !5
  %reverse = shufflevector <16 x i8> %wide.load, <16 x i8> poison, <16 x i32> <i32 15, i32 14, i32 13, i32 12, i32 11, i32 10, i32 9, i32 8, i32 7, i32 6, i32 5, i32 4, i32 3, i32 2, i32 1, i32 0>
  %wide.load17 = load <16 x i8>, ptr %11, align 1, !tbaa !5
  %reverse18 = shufflevector <16 x i8> %wide.load17, <16 x i8> poison, <16 x i32> <i32 15, i32 14, i32 13, i32 12, i32 11, i32 10, i32 9, i32 8, i32 7, i32 6, i32 5, i32 4, i32 3, i32 2, i32 1, i32 0>
  %12 = getelementptr inbounds i8, ptr %4, i64 %index
  %13 = getelementptr inbounds i8, ptr %12, i64 16
  store <16 x i8> %reverse, ptr %12, align 1, !tbaa !5
  store <16 x i8> %reverse18, ptr %13, align 1, !tbaa !5
  %index.next = add nuw i64 %index, 32
  %14 = icmp eq i64 %index.next, %n.vec
  br i1 %14, label %middle.block, label %vector.body, !llvm.loop !8

middle.block:                                     ; preds = %vector.body
  %cmp.n = icmp eq i64 %n.vec, %wide.trip.count
  br i1 %cmp.n, label %.loopexit, label %vec.epilog.iter.check

vec.epilog.iter.check:                            ; preds = %middle.block
  %n.vec.remaining = and i64 %wide.trip.count, 24
  %min.epilog.iters.check = icmp eq i64 %n.vec.remaining, 0
  br i1 %min.epilog.iters.check, label %vec.epilog.scalar.ph.preheader, label %vec.epilog.ph

vec.epilog.ph:                                    ; preds = %vector.main.loop.iter.check, %vec.epilog.iter.check
  %vec.epilog.resume.val = phi i64 [ %n.vec, %vec.epilog.iter.check ], [ 0, %vector.main.loop.iter.check ]
  %n.vec20 = and i64 %wide.trip.count, 2147483640
  %invariant.gep26 = getelementptr i8, ptr %invariant.gep, i64 -7
  br label %vec.epilog.vector.body

vec.epilog.vector.body:                           ; preds = %vec.epilog.vector.body, %vec.epilog.ph
  %index21 = phi i64 [ %vec.epilog.resume.val, %vec.epilog.ph ], [ %index.next24, %vec.epilog.vector.body ]
  %15 = sub nsw i64 0, %index21
  %gep27 = getelementptr i8, ptr %invariant.gep26, i64 %15
  %wide.load22 = load <8 x i8>, ptr %gep27, align 1, !tbaa !5
  %reverse23 = shufflevector <8 x i8> %wide.load22, <8 x i8> poison, <8 x i32> <i32 7, i32 6, i32 5, i32 4, i32 3, i32 2, i32 1, i32 0>
  %16 = getelementptr inbounds i8, ptr %4, i64 %index21
  store <8 x i8> %reverse23, ptr %16, align 1, !tbaa !5
  %index.next24 = add nuw i64 %index21, 8
  %17 = icmp eq i64 %index.next24, %n.vec20
  br i1 %17, label %vec.epilog.middle.block, label %vec.epilog.vector.body, !llvm.loop !12

vec.epilog.middle.block:                          ; preds = %vec.epilog.vector.body
  %cmp.n25 = icmp eq i64 %n.vec20, %wide.trip.count
  br i1 %cmp.n25, label %.loopexit, label %vec.epilog.scalar.ph.preheader

vec.epilog.scalar.ph.preheader:                   ; preds = %vec.epilog.middle.block, %iter.check, %vec.epilog.iter.check
  %indvars.iv.ph = phi i64 [ 0, %iter.check ], [ %n.vec, %vec.epilog.iter.check ], [ %n.vec20, %vec.epilog.middle.block ]
  br label %vec.epilog.scalar.ph

vec.epilog.scalar.ph:                             ; preds = %vec.epilog.scalar.ph.preheader, %vec.epilog.scalar.ph
  %indvars.iv = phi i64 [ %indvars.iv.next, %vec.epilog.scalar.ph ], [ %indvars.iv.ph, %vec.epilog.scalar.ph.preheader ]
  %18 = sub nsw i64 0, %indvars.iv
  %gep = getelementptr i8, ptr %invariant.gep, i64 %18
  %19 = load i8, ptr %gep, align 1, !tbaa !5
  %20 = getelementptr inbounds i8, ptr %4, i64 %indvars.iv
  store i8 %19, ptr %20, align 1, !tbaa !5
  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
  %exitcond.not = icmp eq i64 %indvars.iv.next, %wide.trip.count
  br i1 %exitcond.not, label %.loopexit, label %vec.epilog.scalar.ph, !llvm.loop !13

.loopexit:                                        ; preds = %vec.epilog.scalar.ph, %middle.block, %vec.epilog.middle.block, %2
  ret ptr %4
}

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

attributes #0 = { mustprogress nofree nounwind memory(write, argmem: read, inaccessiblemem: readwrite) 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 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 #2 = { 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++ TBAA"}
!8 = distinct !{!8, !9, !10, !11}
!9 = !{!"llvm.loop.mustprogress"}
!10 = !{!"llvm.loop.isvectorized", i32 1}
!11 = !{!"llvm.loop.unroll.runtime.disable"}
!12 = distinct !{!12, !9, !10, !11}
!13 = distinct !{!13, !9, !11, !10}


; Effective O3 passes: CorrelatedValuePropagationPass,EarlyCSEPass,GlobalOptPass,IPSCCPPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,JumpThreadingPass,LICMPass,LoopLoadEliminationPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,LoopVectorizePass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass,TailCallElimPass