; LLVM IR from smv1999/CompetitiveProgrammingQuestionBank :: Strings (alternating_characters)

; 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 i32 @alternatingCharacters(ptr noundef %0) #0 {
  %2 = alloca ptr, align 8
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  store ptr %0, ptr %2, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %3) #3
  %6 = load ptr, ptr %2, align 8, !tbaa !5
  %7 = call i64 @strlen(ptr noundef %6) #4
  %8 = trunc i64 %7 to i32
  store i32 %8, ptr %3, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #3
  store i32 0, 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 %9

9:                                                ; preds = %32, %1
  %10 = load i32, ptr %5, align 4, !tbaa !9
  %11 = load i32, ptr %3, align 4, !tbaa !9
  %12 = icmp slt i32 %10, %11
  br i1 %12, label %13, label %35

13:                                               ; preds = %9
  %14 = load ptr, ptr %2, align 8, !tbaa !5
  %15 = load i32, ptr %5, align 4, !tbaa !9
  %16 = sext i32 %15 to i64
  %17 = getelementptr inbounds i8, ptr %14, i64 %16
  %18 = load i8, ptr %17, align 1, !tbaa !11
  %19 = sext i8 %18 to i32
  %20 = load ptr, ptr %2, align 8, !tbaa !5
  %21 = load i32, ptr %5, align 4, !tbaa !9
  %22 = add nsw i32 %21, 1
  %23 = sext i32 %22 to i64
  %24 = getelementptr inbounds i8, ptr %20, i64 %23
  %25 = load i8, ptr %24, align 1, !tbaa !11
  %26 = sext i8 %25 to i32
  %27 = icmp eq i32 %19, %26
  br i1 %27, label %28, label %31

28:                                               ; preds = %13
  %29 = load i32, ptr %4, align 4, !tbaa !9
  %30 = add nsw i32 %29, 1
  store i32 %30, ptr %4, align 4, !tbaa !9
  br label %31

31:                                               ; preds = %28, %13
  br label %32

32:                                               ; preds = %31
  %33 = load i32, ptr %5, align 4, !tbaa !9
  %34 = add nsw i32 %33, 1
  store i32 %34, ptr %5, align 4, !tbaa !9
  br label %9, !llvm.loop !12

35:                                               ; preds = %9
  %36 = load i32, ptr %4, align 4, !tbaa !9
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #3
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #3
  call void @llvm.lifetime.end.p0(i64 4, ptr %3) #3
  ret i32 %36
}

; 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(argmem: read) uwtable
define dso_local i32 @alternatingCharacters(ptr nocapture noundef readonly %0) local_unnamed_addr #0 {
  %2 = tail call i64 @strlen(ptr noundef nonnull dereferenceable(1) %0) #3
  %3 = trunc i64 %2 to i32
  %4 = icmp sgt i32 %3, 0
  br i1 %4, label %.lr.ph.preheader, label %._crit_edge

.lr.ph.preheader:                                 ; preds = %1
  %wide.trip.count = and i64 %2, 2147483647
  %.pre = load i8, ptr %0, align 1, !tbaa !5
  %min.iters.check = icmp ult i64 %wide.trip.count, 8
  br i1 %min.iters.check, label %.lr.ph.preheader15, label %vector.ph

vector.ph:                                        ; preds = %.lr.ph.preheader
  %n.mod.vf = and i64 %2, 7
  %n.vec = sub nsw i64 %wide.trip.count, %n.mod.vf
  %vector.recur.init = insertelement <4 x i8> poison, i8 %.pre, i64 3
  br label %vector.body

vector.body:                                      ; preds = %vector.body, %vector.ph
  %index = phi i64 [ 0, %vector.ph ], [ %index.next, %vector.body ]
  %vector.recur = phi <4 x i8> [ %vector.recur.init, %vector.ph ], [ %wide.load14, %vector.body ]
  %vec.phi = phi <4 x i32> [ zeroinitializer, %vector.ph ], [ %14, %vector.body ]
  %vec.phi13 = phi <4 x i32> [ zeroinitializer, %vector.ph ], [ %15, %vector.body ]
  %5 = or disjoint i64 %index, 1
  %6 = getelementptr inbounds i8, ptr %0, i64 %5
  %7 = getelementptr inbounds i8, ptr %6, i64 4
  %wide.load = load <4 x i8>, ptr %6, align 1, !tbaa !5
  %wide.load14 = load <4 x i8>, ptr %7, align 1, !tbaa !5
  %8 = shufflevector <4 x i8> %vector.recur, <4 x i8> %wide.load, <4 x i32> <i32 3, i32 4, i32 5, i32 6>
  %9 = shufflevector <4 x i8> %wide.load, <4 x i8> %wide.load14, <4 x i32> <i32 3, i32 4, i32 5, i32 6>
  %10 = icmp eq <4 x i8> %8, %wide.load
  %11 = icmp eq <4 x i8> %9, %wide.load14
  %12 = zext <4 x i1> %10 to <4 x i32>
  %13 = zext <4 x i1> %11 to <4 x i32>
  %14 = add <4 x i32> %vec.phi, %12
  %15 = add <4 x i32> %vec.phi13, %13
  %index.next = add nuw i64 %index, 8
  %16 = icmp eq i64 %index.next, %n.vec
  br i1 %16, label %middle.block, label %vector.body, !llvm.loop !8

middle.block:                                     ; preds = %vector.body
  %bin.rdx = add <4 x i32> %15, %14
  %17 = tail call i32 @llvm.vector.reduce.add.v4i32(<4 x i32> %bin.rdx)
  %vector.recur.extract = extractelement <4 x i8> %wide.load14, i64 3
  %cmp.n = icmp eq i64 %n.mod.vf, 0
  br i1 %cmp.n, label %._crit_edge, label %.lr.ph.preheader15

.lr.ph.preheader15:                               ; preds = %middle.block, %.lr.ph.preheader
  %.ph = phi i8 [ %.pre, %.lr.ph.preheader ], [ %vector.recur.extract, %middle.block ]
  %indvars.iv.ph = phi i64 [ 0, %.lr.ph.preheader ], [ %n.vec, %middle.block ]
  %.0910.ph = phi i32 [ 0, %.lr.ph.preheader ], [ %17, %middle.block ]
  br label %.lr.ph

.lr.ph:                                           ; preds = %.lr.ph.preheader15, %.lr.ph
  %18 = phi i8 [ %20, %.lr.ph ], [ %.ph, %.lr.ph.preheader15 ]
  %indvars.iv = phi i64 [ %indvars.iv.next, %.lr.ph ], [ %indvars.iv.ph, %.lr.ph.preheader15 ]
  %.0910 = phi i32 [ %spec.select, %.lr.ph ], [ %.0910.ph, %.lr.ph.preheader15 ]
  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
  %19 = getelementptr inbounds i8, ptr %0, i64 %indvars.iv.next
  %20 = load i8, ptr %19, align 1, !tbaa !5
  %21 = icmp eq i8 %18, %20
  %22 = zext i1 %21 to i32
  %spec.select = add nuw nsw i32 %.0910, %22
  %exitcond.not = icmp eq i64 %indvars.iv.next, %wide.trip.count
  br i1 %exitcond.not, label %._crit_edge, label %.lr.ph, !llvm.loop !12

._crit_edge:                                      ; preds = %.lr.ph, %middle.block, %1
  %.09.lcssa = phi i32 [ 0, %1 ], [ %17, %middle.block ], [ %spec.select, %.lr.ph ]
  ret i32 %.09.lcssa
}

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

; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
declare i32 @llvm.vector.reduce.add.v4i32(<4 x i32>) #2

attributes #0 = { nofree 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 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 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }
attributes #3 = { 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, !10, !11}
!9 = !{!"llvm.loop.mustprogress"}
!10 = !{!"llvm.loop.isvectorized", i32 1}
!11 = !{!"llvm.loop.unroll.runtime.disable"}
!12 = distinct !{!12, !9, !11, !10}


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