; LLVM IR from DimitrisJim/leetcode_solutions :: C/Algorithms (1720)

; 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 @decode(ptr noundef %0, i32 noundef %1, i32 noundef %2, ptr noundef %3) #0 {
  %5 = alloca ptr, align 8
  %6 = alloca i32, align 4
  %7 = alloca i32, align 4
  %8 = alloca ptr, align 8
  %9 = alloca i32, align 4
  %10 = alloca i32, align 4
  %11 = alloca i32, align 4
  store ptr %0, ptr %5, align 8, !tbaa !5
  store i32 %1, ptr %6, align 4, !tbaa !9
  store i32 %2, ptr %7, align 4, !tbaa !9
  store ptr %3, ptr %8, align 8, !tbaa !5
  %12 = load i32, ptr %6, align 4, !tbaa !9
  %13 = add nsw i32 %12, 1
  %14 = load ptr, ptr %8, align 8, !tbaa !5
  store i32 %13, ptr %14, align 4, !tbaa !9
  %15 = load ptr, ptr %5, align 8, !tbaa !5
  %16 = load ptr, ptr %8, align 8, !tbaa !5
  %17 = load i32, ptr %16, align 4, !tbaa !9
  %18 = sext i32 %17 to i64
  %19 = mul i64 %18, 4
  %20 = call ptr @realloc(ptr noundef %15, i64 noundef %19) #3
  store ptr %20, ptr %5, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %9) #4
  %21 = load i32, ptr %7, align 4, !tbaa !9
  store i32 %21, ptr %9, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %10) #4
  store i32 1, ptr %10, align 4, !tbaa !9
  br label %22

22:                                               ; preds = %46, %4
  %23 = load i32, ptr %10, align 4, !tbaa !9
  %24 = load i32, ptr %6, align 4, !tbaa !9
  %25 = icmp sle i32 %23, %24
  br i1 %25, label %27, label %26

26:                                               ; preds = %22
  call void @llvm.lifetime.end.p0(i64 4, ptr %10) #4
  br label %49

27:                                               ; preds = %22
  call void @llvm.lifetime.start.p0(i64 4, ptr %11) #4
  %28 = load ptr, ptr %5, align 8, !tbaa !5
  %29 = load i32, ptr %10, align 4, !tbaa !9
  %30 = sext i32 %29 to i64
  %31 = getelementptr inbounds i32, ptr %28, i64 %30
  %32 = load i32, ptr %31, align 4, !tbaa !9
  store i32 %32, ptr %11, align 4, !tbaa !9
  %33 = load i32, ptr %9, align 4, !tbaa !9
  %34 = load ptr, ptr %5, align 8, !tbaa !5
  %35 = load i32, ptr %10, align 4, !tbaa !9
  %36 = sub nsw i32 %35, 1
  %37 = sext i32 %36 to i64
  %38 = getelementptr inbounds i32, ptr %34, i64 %37
  %39 = load i32, ptr %38, align 4, !tbaa !9
  %40 = xor i32 %33, %39
  %41 = load ptr, ptr %5, align 8, !tbaa !5
  %42 = load i32, ptr %10, align 4, !tbaa !9
  %43 = sext i32 %42 to i64
  %44 = getelementptr inbounds i32, ptr %41, i64 %43
  store i32 %40, ptr %44, align 4, !tbaa !9
  %45 = load i32, ptr %11, align 4, !tbaa !9
  store i32 %45, ptr %9, align 4, !tbaa !9
  call void @llvm.lifetime.end.p0(i64 4, ptr %11) #4
  br label %46

46:                                               ; preds = %27
  %47 = load i32, ptr %10, align 4, !tbaa !9
  %48 = add nsw i32 %47, 1
  store i32 %48, ptr %10, align 4, !tbaa !9
  br label %22, !llvm.loop !11

49:                                               ; preds = %26
  %50 = load i32, ptr %7, align 4, !tbaa !9
  %51 = load ptr, ptr %5, align 8, !tbaa !5
  %52 = getelementptr inbounds i32, ptr %51, i64 0
  store i32 %50, ptr %52, align 4, !tbaa !9
  %53 = load ptr, ptr %5, align 8, !tbaa !5
  call void @llvm.lifetime.end.p0(i64 4, ptr %9) #4
  ret ptr %53
}

; Function Attrs: nounwind allocsize(1)
declare ptr @realloc(ptr noundef, i64 noundef) #1

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #2

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #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 = { nounwind allocsize(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 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #3 = { nounwind allocsize(1) }
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 = !{!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 noalias noundef ptr @decode(ptr nocapture noundef %0, i32 noundef %1, i32 noundef %2, ptr nocapture noundef writeonly %3) local_unnamed_addr #0 {
  %5 = add i32 %1, 1
  store i32 %5, ptr %3, align 4, !tbaa !5
  %6 = sext i32 %5 to i64
  %7 = shl nsw i64 %6, 2
  %8 = tail call ptr @realloc(ptr noundef %0, i64 noundef %7) #2
  %.not19 = icmp slt i32 %1, 1
  br i1 %.not19, label %._crit_edge, label %.lr.ph.preheader

.lr.ph.preheader:                                 ; preds = %4
  %wide.trip.count = zext i32 %5 to i64
  %load_initial = load i32, ptr %8, align 4
  %9 = add nsw i64 %wide.trip.count, -1
  %10 = add nsw i64 %wide.trip.count, -2
  %xtraiter = and i64 %9, 3
  %11 = icmp ult i64 %10, 3
  br i1 %11, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph.preheader.new

.lr.ph.preheader.new:                             ; preds = %.lr.ph.preheader
  %unroll_iter = and i64 %9, -4
  %invariant.gep = getelementptr inbounds i8, ptr %8, i64 4
  %invariant.gep24 = getelementptr inbounds i8, ptr %8, i64 8
  %invariant.gep26 = getelementptr inbounds i8, ptr %8, i64 12
  br label %.lr.ph

._crit_edge.loopexit.unr-lcssa:                   ; preds = %.lr.ph, %.lr.ph.preheader
  %store_forwarded.unr = phi i32 [ %load_initial, %.lr.ph.preheader ], [ %23, %.lr.ph ]
  %indvars.iv.unr = phi i64 [ 1, %.lr.ph.preheader ], [ %indvars.iv.next.3, %.lr.ph ]
  %.01820.unr = phi i32 [ %2, %.lr.ph.preheader ], [ %22, %.lr.ph ]
  %lcmp.mod.not = icmp eq i64 %xtraiter, 0
  br i1 %lcmp.mod.not, label %._crit_edge, label %.lr.ph.epil

.lr.ph.epil:                                      ; preds = %._crit_edge.loopexit.unr-lcssa, %.lr.ph.epil
  %store_forwarded.epil = phi i32 [ %14, %.lr.ph.epil ], [ %store_forwarded.unr, %._crit_edge.loopexit.unr-lcssa ]
  %indvars.iv.epil = phi i64 [ %indvars.iv.next.epil, %.lr.ph.epil ], [ %indvars.iv.unr, %._crit_edge.loopexit.unr-lcssa ]
  %.01820.epil = phi i32 [ %13, %.lr.ph.epil ], [ %.01820.unr, %._crit_edge.loopexit.unr-lcssa ]
  %epil.iter = phi i64 [ %epil.iter.next, %.lr.ph.epil ], [ 0, %._crit_edge.loopexit.unr-lcssa ]
  %12 = getelementptr inbounds i32, ptr %8, i64 %indvars.iv.epil
  %13 = load i32, ptr %12, align 4, !tbaa !5
  %14 = xor i32 %store_forwarded.epil, %.01820.epil
  store i32 %14, ptr %12, align 4, !tbaa !5
  %indvars.iv.next.epil = add nuw nsw i64 %indvars.iv.epil, 1
  %epil.iter.next = add i64 %epil.iter, 1
  %epil.iter.cmp.not = icmp eq i64 %epil.iter.next, %xtraiter
  br i1 %epil.iter.cmp.not, label %._crit_edge, label %.lr.ph.epil, !llvm.loop !9

._crit_edge:                                      ; preds = %._crit_edge.loopexit.unr-lcssa, %.lr.ph.epil, %4
  store i32 %2, ptr %8, align 4, !tbaa !5
  ret ptr %8

.lr.ph:                                           ; preds = %.lr.ph, %.lr.ph.preheader.new
  %store_forwarded = phi i32 [ %load_initial, %.lr.ph.preheader.new ], [ %23, %.lr.ph ]
  %indvars.iv = phi i64 [ 1, %.lr.ph.preheader.new ], [ %indvars.iv.next.3, %.lr.ph ]
  %.01820 = phi i32 [ %2, %.lr.ph.preheader.new ], [ %22, %.lr.ph ]
  %niter = phi i64 [ 0, %.lr.ph.preheader.new ], [ %niter.next.3, %.lr.ph ]
  %15 = getelementptr inbounds i32, ptr %8, i64 %indvars.iv
  %16 = load i32, ptr %15, align 4, !tbaa !5
  %17 = xor i32 %store_forwarded, %.01820
  store i32 %17, ptr %15, align 4, !tbaa !5
  %gep = getelementptr inbounds i32, ptr %invariant.gep, i64 %indvars.iv
  %18 = load i32, ptr %gep, align 4, !tbaa !5
  %19 = xor i32 %17, %16
  store i32 %19, ptr %gep, align 4, !tbaa !5
  %gep25 = getelementptr inbounds i32, ptr %invariant.gep24, i64 %indvars.iv
  %20 = load i32, ptr %gep25, align 4, !tbaa !5
  %21 = xor i32 %19, %18
  store i32 %21, ptr %gep25, align 4, !tbaa !5
  %gep27 = getelementptr inbounds i32, ptr %invariant.gep26, i64 %indvars.iv
  %22 = load i32, ptr %gep27, align 4, !tbaa !5
  %23 = xor i32 %21, %20
  store i32 %23, ptr %gep27, align 4, !tbaa !5
  %indvars.iv.next.3 = add nuw nsw i64 %indvars.iv, 4
  %niter.next.3 = add i64 %niter, 4
  %niter.ncmp.3 = icmp eq i64 %niter.next.3, %unroll_iter
  br i1 %niter.ncmp.3, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph, !llvm.loop !11
}

; Function Attrs: mustprogress nounwind willreturn allockind("realloc") allocsize(1) memory(argmem: readwrite, inaccessiblemem: readwrite)
declare noalias noundef ptr @realloc(ptr allocptr nocapture noundef, i64 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 = { mustprogress nounwind willreturn allockind("realloc") allocsize(1) memory(argmem: readwrite, 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(1) }

!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 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}
!9 = distinct !{!9, !10}
!10 = !{!"llvm.loop.unroll.disable"}
!11 = distinct !{!11, !12}
!12 = !{!"llvm.loop.mustprogress"}


; Effective O3 passes: EarlyCSEPass,GVNPass,GlobalOptPass,IPSCCPPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LICMPass,LoopLoadEliminationPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,ReassociatePass,SROAPass,SimplifyCFGPass,TailCallElimPass