; LLVM IR from devparthgarg/Data-Structures-and-Algorithms :: 10. Strings/11 Leftmost Repeating Character (11a Leftmost Repeating Character)

; 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: mustprogress uwtable
define dso_local noundef i32 @_Z17leftMostRepeatingNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE(ptr noundef %0) #0 {
  %2 = alloca i32, align 4
  %3 = alloca ptr, align 8
  %4 = alloca i32, align 4
  %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 4, ptr %4) #3
  %8 = call noundef i64 @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE6lengthEv(ptr noundef nonnull align 8 dereferenceable(32) %0) #3
  %9 = trunc i64 %8 to i32
  store i32 %9, 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
  br label %10

10:                                               ; preds = %44, %1
  %11 = load i32, ptr %5, align 4, !tbaa !9
  %12 = load i32, ptr %4, align 4, !tbaa !9
  %13 = icmp slt i32 %11, %12
  br i1 %13, label %15, label %14

14:                                               ; preds = %10
  store i32 2, ptr %6, align 4
  br label %47

15:                                               ; preds = %10
  call void @llvm.lifetime.start.p0(i64 4, ptr %7) #3
  %16 = load i32, ptr %5, align 4, !tbaa !9
  %17 = add nsw i32 %16, 1
  store i32 %17, ptr %7, align 4, !tbaa !9
  br label %18

18:                                               ; preds = %38, %15
  %19 = load i32, ptr %7, align 4, !tbaa !9
  %20 = load i32, ptr %4, align 4, !tbaa !9
  %21 = icmp slt i32 %19, %20
  br i1 %21, label %23, label %22

22:                                               ; preds = %18
  store i32 5, ptr %6, align 4
  br label %41

23:                                               ; preds = %18
  %24 = load i32, ptr %5, align 4, !tbaa !9
  %25 = sext i32 %24 to i64
  %26 = call noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) %0, i64 noundef %25)
  %27 = load i8, ptr %26, align 1, !tbaa !11
  %28 = sext i8 %27 to i32
  %29 = load i32, ptr %7, align 4, !tbaa !9
  %30 = sext i32 %29 to i64
  %31 = call noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) %0, i64 noundef %30)
  %32 = load i8, ptr %31, align 1, !tbaa !11
  %33 = sext i8 %32 to i32
  %34 = icmp eq i32 %28, %33
  br i1 %34, label %35, label %37

35:                                               ; preds = %23
  %36 = load i32, ptr %5, align 4, !tbaa !9
  store i32 %36, ptr %2, align 4
  store i32 1, ptr %6, align 4
  br label %41

37:                                               ; preds = %23
  br label %38

38:                                               ; preds = %37
  %39 = load i32, ptr %7, align 4, !tbaa !9
  %40 = add nsw i32 %39, 1
  store i32 %40, ptr %7, align 4, !tbaa !9
  br label %18, !llvm.loop !12

41:                                               ; preds = %35, %22
  call void @llvm.lifetime.end.p0(i64 4, ptr %7) #3
  %42 = load i32, ptr %6, align 4
  switch i32 %42, label %47 [
    i32 5, label %43
  ]

43:                                               ; preds = %41
  br label %44

44:                                               ; preds = %43
  %45 = load i32, ptr %5, align 4, !tbaa !9
  %46 = add nsw i32 %45, 1
  store i32 %46, ptr %5, align 4, !tbaa !9
  br label %10, !llvm.loop !14

47:                                               ; preds = %41, %14
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #3
  %48 = load i32, ptr %6, align 4
  switch i32 %48, label %50 [
    i32 2, label %49
  ]

49:                                               ; preds = %47
  store i32 -1, ptr %2, align 4
  store i32 1, ptr %6, align 4
  br label %50

50:                                               ; preds = %49, %47
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #3
  %51 = load i32, ptr %2, align 4
  ret i32 %51
}

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

; Function Attrs: mustprogress nounwind uwtable
declare noundef i64 @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE6lengthEv(ptr noundef nonnull align 8 dereferenceable(32)) #2 align 2

; Function Attrs: mustprogress nounwind uwtable
declare noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32), i64 noundef) #2 align 2

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

attributes #0 = { mustprogress 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 = { 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 #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++ 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: mustprogress nounwind uwtable
define dso_local noundef i32 @_Z17leftMostRepeatingNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE(ptr noundef nonnull %0) local_unnamed_addr #0 {
  %2 = tail call noundef i64 @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE6lengthEv(ptr noundef nonnull align 8 dereferenceable(32) %0) #1
  %3 = trunc i64 %2 to i32
  %.not1925 = icmp sgt i32 %3, 0
  br i1 %.not1925, label %.lr.ph27.preheader, label %.thread

.lr.ph27.preheader:                               ; preds = %1
  %4 = and i64 %2, 2147483647
  %wide.trip.count36 = and i64 %2, 2147483647
  br label %.lr.ph27

.loopexit:                                        ; preds = %5, %.lr.ph27
  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
  %exitcond37.not = icmp eq i64 %indvars.iv.next34, %wide.trip.count36
  br i1 %exitcond37.not, label %.thread, label %.lr.ph27

.lr.ph27:                                         ; preds = %.lr.ph27.preheader, %.loopexit
  %indvars.iv33 = phi i64 [ 0, %.lr.ph27.preheader ], [ %indvars.iv.next34, %.loopexit ]
  %indvars.iv = phi i64 [ 1, %.lr.ph27.preheader ], [ %indvars.iv.next, %.loopexit ]
  %indvars.iv.next34 = add nuw nsw i64 %indvars.iv33, 1
  %.not23 = icmp ult i64 %indvars.iv.next34, %4
  br i1 %.not23, label %.lr.ph, label %.loopexit

5:                                                ; preds = %.lr.ph
  %indvars.iv.next31 = add nuw nsw i64 %indvars.iv30, 1
  %exitcond.not = icmp eq i64 %indvars.iv.next31, %wide.trip.count36
  br i1 %exitcond.not, label %.loopexit, label %.lr.ph, !llvm.loop !5

.lr.ph:                                           ; preds = %.lr.ph27, %5
  %indvars.iv30 = phi i64 [ %indvars.iv.next31, %5 ], [ %indvars.iv, %.lr.ph27 ]
  %6 = tail call noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) %0, i64 noundef %indvars.iv33)
  %7 = load i8, ptr %6, align 1, !tbaa !7
  %8 = tail call noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32) %0, i64 noundef %indvars.iv30)
  %9 = load i8, ptr %8, align 1, !tbaa !7
  %10 = icmp eq i8 %7, %9
  br i1 %10, label %.thread.loopexit, label %5

.thread.loopexit:                                 ; preds = %.lr.ph
  %11 = trunc nuw nsw i64 %indvars.iv33 to i32
  br label %.thread

.thread:                                          ; preds = %.loopexit, %.thread.loopexit, %1
  %spec.select = phi i32 [ -1, %1 ], [ %11, %.thread.loopexit ], [ -1, %.loopexit ]
  ret i32 %spec.select
}

; Function Attrs: mustprogress nounwind uwtable
declare noundef i64 @_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE6lengthEv(ptr noundef nonnull align 8 dereferenceable(32)) local_unnamed_addr #0 align 2

; Function Attrs: mustprogress nounwind uwtable
declare noundef nonnull align 1 dereferenceable(1) ptr @_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEixEm(ptr noundef nonnull align 8 dereferenceable(32), i64 noundef) local_unnamed_addr #0 align 2

attributes #0 = { 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 #1 = { 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"}
!7 = !{!8, !8, i64 0}
!8 = !{!"omnipotent char", !9, i64 0}
!9 = !{!"Simple C++ TBAA"}


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