; LLVM IR from imeplusplus/icpc-notebook :: strings/eertree.ll (Z8get_linki)

; 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"

@s = external dso_local global [1000007 x i8], align 16
@len = external dso_local global [1000007 x i32], align 16
@link = external dso_local global [1000007 x i32], align 16
@n = external dso_local global i32, align 4

; Function Attrs: mustprogress nounwind uwtable
define dso_local noundef i32 @_Z8get_linki(i32 noundef %0) #0 {
  %2 = alloca i32, align 4
  store i32 %0, ptr %2, align 4, !tbaa !5
  br label %3

3:                                                ; preds = %22, %1
  %4 = load i32, ptr @n, align 4, !tbaa !5
  %5 = load i32, ptr %2, align 4, !tbaa !5
  %6 = sext i32 %5 to i64
  %7 = getelementptr inbounds [1000007 x i32], ptr @len, i64 0, i64 %6
  %8 = load i32, ptr %7, align 4, !tbaa !5
  %9 = sub nsw i32 %4, %8
  %10 = sub nsw i32 %9, 2
  %11 = sext i32 %10 to i64
  %12 = getelementptr inbounds [1000007 x i8], ptr @s, i64 0, i64 %11
  %13 = load i8, ptr %12, align 1, !tbaa !9
  %14 = sext i8 %13 to i32
  %15 = load i32, ptr @n, align 4, !tbaa !5
  %16 = sub nsw i32 %15, 1
  %17 = sext i32 %16 to i64
  %18 = getelementptr inbounds [1000007 x i8], ptr @s, i64 0, i64 %17
  %19 = load i8, ptr %18, align 1, !tbaa !9
  %20 = sext i8 %19 to i32
  %21 = icmp ne i32 %14, %20
  br i1 %21, label %22, label %27

22:                                               ; preds = %3
  %23 = load i32, ptr %2, align 4, !tbaa !5
  %24 = sext i32 %23 to i64
  %25 = getelementptr inbounds [1000007 x i32], ptr @link, i64 0, i64 %24
  %26 = load i32, ptr %25, align 4, !tbaa !5
  store i32 %26, ptr %2, align 4, !tbaa !5
  br label %3, !llvm.loop !10

27:                                               ; preds = %3
  %28 = load i32, ptr %2, align 4, !tbaa !5
  ret i32 %28
}

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" }

!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++ TBAA"}
!9 = !{!7, !7, i64 0}
!10 = distinct !{!10, !11}
!11 = !{!"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"

@s = external dso_local local_unnamed_addr global [1000007 x i8], align 16
@len = external dso_local local_unnamed_addr global [1000007 x i32], align 16
@link = external dso_local local_unnamed_addr global [1000007 x i32], align 16
@n = external dso_local local_unnamed_addr global i32, align 4

; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(read, argmem: none, inaccessiblemem: none) uwtable
define dso_local noundef i32 @_Z8get_linki(i32 noundef %0) local_unnamed_addr #0 {
  %2 = load i32, ptr @n, align 4, !tbaa !5
  %3 = add i32 %2, -2
  %4 = add nsw i32 %2, -1
  %5 = sext i32 %4 to i64
  %6 = getelementptr inbounds [1000007 x i8], ptr @s, i64 0, i64 %5
  %7 = load i8, ptr %6, align 1, !tbaa !9
  %8 = sext i32 %0 to i64
  %9 = getelementptr inbounds [1000007 x i32], ptr @len, i64 0, i64 %8
  %10 = load i32, ptr %9, align 4, !tbaa !5
  %11 = sub i32 %3, %10
  %12 = sext i32 %11 to i64
  %13 = getelementptr inbounds [1000007 x i8], ptr @s, i64 0, i64 %12
  %14 = load i8, ptr %13, align 1, !tbaa !9
  %.not4 = icmp eq i8 %14, %7
  br i1 %.not4, label %._crit_edge, label %.lr.ph

.lr.ph:                                           ; preds = %1, %.lr.ph
  %15 = phi i64 [ %18, %.lr.ph ], [ %8, %1 ]
  %16 = getelementptr inbounds [1000007 x i32], ptr @link, i64 0, i64 %15
  %17 = load i32, ptr %16, align 4, !tbaa !5
  %18 = sext i32 %17 to i64
  %19 = getelementptr inbounds [1000007 x i32], ptr @len, i64 0, i64 %18
  %20 = load i32, ptr %19, align 4, !tbaa !5
  %21 = sub i32 %3, %20
  %22 = sext i32 %21 to i64
  %23 = getelementptr inbounds [1000007 x i8], ptr @s, i64 0, i64 %22
  %24 = load i8, ptr %23, align 1, !tbaa !9
  %.not = icmp eq i8 %24, %7
  br i1 %.not, label %._crit_edge, label %.lr.ph, !llvm.loop !10

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

attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn memory(read, argmem: none, inaccessiblemem: none) 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" }

!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++ TBAA"}
!9 = !{!7, !7, i64 0}
!10 = distinct !{!10, !11}
!11 = !{!"llvm.loop.mustprogress"}


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