; LLVM IR from Hunterdii/GeeksforGeeks-POTD :: December 2024 GFG SOLUTION (December-01)

; 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 signext i8 @nonRepeatingChar(ptr noundef %0) #0 {
  %2 = alloca i8, align 1
  %3 = alloca ptr, align 8
  %4 = alloca [26 x i32], align 16
  %5 = alloca i32, align 4
  %6 = alloca i32, align 4
  %7 = alloca i32, align 4
  store ptr %0, ptr %3, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 104, ptr %4) #3
  call void @llvm.memset.p0.i64(ptr align 16 %4, i8 0, i64 104, i1 false)
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #3
  store i32 0, ptr %5, align 4, !tbaa !9
  br label %8

8:                                                ; preds = %29, %1
  %9 = load ptr, ptr %3, align 8, !tbaa !5
  %10 = load i32, ptr %5, align 4, !tbaa !9
  %11 = sext i32 %10 to i64
  %12 = getelementptr inbounds i8, ptr %9, i64 %11
  %13 = load i8, ptr %12, align 1, !tbaa !11
  %14 = sext i8 %13 to i32
  %15 = icmp ne i32 %14, 0
  br i1 %15, label %17, label %16

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

17:                                               ; preds = %8
  %18 = load ptr, ptr %3, align 8, !tbaa !5
  %19 = load i32, ptr %5, align 4, !tbaa !9
  %20 = sext i32 %19 to i64
  %21 = getelementptr inbounds i8, ptr %18, i64 %20
  %22 = load i8, ptr %21, align 1, !tbaa !11
  %23 = sext i8 %22 to i32
  %24 = sub nsw i32 %23, 97
  %25 = sext i32 %24 to i64
  %26 = getelementptr inbounds [26 x i32], ptr %4, i64 0, i64 %25
  %27 = load i32, ptr %26, align 4, !tbaa !9
  %28 = add nsw i32 %27, 1
  store i32 %28, ptr %26, align 4, !tbaa !9
  br label %29

29:                                               ; preds = %17
  %30 = load i32, ptr %5, align 4, !tbaa !9
  %31 = add nsw i32 %30, 1
  store i32 %31, ptr %5, align 4, !tbaa !9
  br label %8, !llvm.loop !12

32:                                               ; preds = %16
  call void @llvm.lifetime.start.p0(i64 4, ptr %6) #3
  store i32 0, ptr %6, align 4, !tbaa !9
  br label %33

33:                                               ; preds = %61, %32
  %34 = load ptr, ptr %3, align 8, !tbaa !5
  %35 = load i32, ptr %6, align 4, !tbaa !9
  %36 = sext i32 %35 to i64
  %37 = getelementptr inbounds i8, ptr %34, i64 %36
  %38 = load i8, ptr %37, align 1, !tbaa !11
  %39 = sext i8 %38 to i32
  %40 = icmp ne i32 %39, 0
  br i1 %40, label %42, label %41

41:                                               ; preds = %33
  store i32 5, ptr %7, align 4
  br label %64

42:                                               ; preds = %33
  %43 = load ptr, ptr %3, align 8, !tbaa !5
  %44 = load i32, ptr %6, align 4, !tbaa !9
  %45 = sext i32 %44 to i64
  %46 = getelementptr inbounds i8, ptr %43, i64 %45
  %47 = load i8, ptr %46, align 1, !tbaa !11
  %48 = sext i8 %47 to i32
  %49 = sub nsw i32 %48, 97
  %50 = sext i32 %49 to i64
  %51 = getelementptr inbounds [26 x i32], ptr %4, i64 0, i64 %50
  %52 = load i32, ptr %51, align 4, !tbaa !9
  %53 = icmp eq i32 %52, 1
  br i1 %53, label %54, label %60

54:                                               ; preds = %42
  %55 = load ptr, ptr %3, align 8, !tbaa !5
  %56 = load i32, ptr %6, align 4, !tbaa !9
  %57 = sext i32 %56 to i64
  %58 = getelementptr inbounds i8, ptr %55, i64 %57
  %59 = load i8, ptr %58, align 1, !tbaa !11
  store i8 %59, ptr %2, align 1
  store i32 1, ptr %7, align 4
  br label %64

60:                                               ; preds = %42
  br label %61

61:                                               ; preds = %60
  %62 = load i32, ptr %6, align 4, !tbaa !9
  %63 = add nsw i32 %62, 1
  store i32 %63, ptr %6, align 4, !tbaa !9
  br label %33, !llvm.loop !14

64:                                               ; preds = %54, %41
  call void @llvm.lifetime.end.p0(i64 4, ptr %6) #3
  %65 = load i32, ptr %7, align 4
  switch i32 %65, label %67 [
    i32 5, label %66
  ]

66:                                               ; preds = %64
  store i8 36, ptr %2, align 1
  store i32 1, ptr %7, align 4
  br label %67

67:                                               ; preds = %66, %64
  call void @llvm.lifetime.end.p0(i64 104, ptr %4) #3
  %68 = load i8, ptr %2, align 1
  ret i8 %68
}

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

; Function Attrs: nocallback nofree nounwind willreturn memory(argmem: write)
declare void @llvm.memset.p0.i64(ptr nocapture writeonly, i8, i64, i1 immarg) #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 = { nocallback nofree nounwind willreturn memory(argmem: write) }
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 = !{!7, !7, i64 0}
!12 = distinct !{!12, !13}
!13 = !{!"llvm.loop.mustprogress"}
!14 = distinct !{!14, !13}


; 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 norecurse nosync nounwind memory(argmem: read) uwtable
define dso_local signext i8 @nonRepeatingChar(ptr nocapture noundef readonly %0) local_unnamed_addr #0 {
  %2 = alloca [26 x i32], align 16
  call void @llvm.lifetime.start.p0(i64 104, ptr nonnull %2) #3
  call void @llvm.memset.p0.i64(ptr noundef nonnull align 16 dereferenceable(104) %2, i8 0, i64 104, i1 false)
  %3 = load i8, ptr %0, align 1, !tbaa !5
  %.not19 = icmp eq i8 %3, 0
  br i1 %.not19, label %._crit_edge, label %.lr.ph

.preheader:                                       ; preds = %.lr.ph
  br i1 %.not19, label %._crit_edge, label %.lr.ph23

.lr.ph:                                           ; preds = %1, %.lr.ph
  %indvars.iv = phi i64 [ %indvars.iv.next, %.lr.ph ], [ 0, %1 ]
  %4 = phi i8 [ %11, %.lr.ph ], [ %3, %1 ]
  %5 = sext i8 %4 to i64
  %6 = add nsw i64 %5, -97
  %7 = getelementptr inbounds [26 x i32], ptr %2, i64 0, i64 %6
  %8 = load i32, ptr %7, align 4, !tbaa !8
  %9 = add nsw i32 %8, 1
  store i32 %9, ptr %7, align 4, !tbaa !8
  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
  %10 = getelementptr inbounds i8, ptr %0, i64 %indvars.iv.next
  %11 = load i8, ptr %10, align 1, !tbaa !5
  %.not = icmp eq i8 %11, 0
  br i1 %.not, label %.preheader, label %.lr.ph, !llvm.loop !10

12:                                               ; preds = %.lr.ph23
  %indvars.iv.next27 = add nuw nsw i64 %indvars.iv26, 1
  %13 = getelementptr inbounds i8, ptr %0, i64 %indvars.iv.next27
  %14 = load i8, ptr %13, align 1, !tbaa !5
  %.not18 = icmp eq i8 %14, 0
  br i1 %.not18, label %._crit_edge, label %.lr.ph23, !llvm.loop !12

.lr.ph23:                                         ; preds = %.preheader, %12
  %indvars.iv26 = phi i64 [ %indvars.iv.next27, %12 ], [ 0, %.preheader ]
  %15 = phi i8 [ %14, %12 ], [ %3, %.preheader ]
  %16 = sext i8 %15 to i64
  %17 = add nsw i64 %16, -97
  %18 = getelementptr inbounds [26 x i32], ptr %2, i64 0, i64 %17
  %19 = load i32, ptr %18, align 4, !tbaa !8
  %20 = icmp eq i32 %19, 1
  br i1 %20, label %._crit_edge, label %12

._crit_edge:                                      ; preds = %12, %.lr.ph23, %1, %.preheader
  %spec.select = phi i8 [ 36, %.preheader ], [ 36, %1 ], [ %15, %.lr.ph23 ], [ 36, %12 ]
  call void @llvm.lifetime.end.p0(i64 104, ptr nonnull %2) #3
  ret i8 %spec.select
}

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

; Function Attrs: mustprogress nocallback nofree nounwind willreturn memory(argmem: write)
declare void @llvm.memset.p0.i64(ptr nocapture writeonly, i8, i64, i1 immarg) #2

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

attributes #0 = { nofree norecurse nosync nounwind memory(argmem: read) 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 nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #2 = { mustprogress nocallback nofree nounwind willreturn memory(argmem: write) }
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 = !{!"omnipotent char", !7, i64 0}
!7 = !{!"Simple C/C++ TBAA"}
!8 = !{!9, !9, i64 0}
!9 = !{!"int", !6, i64 0}
!10 = distinct !{!10, !11}
!11 = !{!"llvm.loop.mustprogress"}
!12 = distinct !{!12, !11}


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