; LLVM IR from narke/Aragveli :: src/kernel/lib/c (string)

; 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: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #0

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #0

; Function Attrs: nounwind uwtable
define dso_local i64 @strnlen(ptr noundef %0, i64 noundef %1) #1 {
  %3 = alloca ptr, align 8
  %4 = alloca i64, align 8
  %5 = alloca i64, align 8
  store ptr %0, ptr %3, align 8, !tbaa !5
  store i64 %1, ptr %4, align 8, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 8, ptr %5) #2
  store i64 0, ptr %5, align 8, !tbaa !9
  br label %6

6:                                                ; preds = %18, %2
  %7 = load ptr, ptr %3, align 8, !tbaa !5
  %8 = getelementptr inbounds i8, ptr %7, i32 1
  store ptr %8, ptr %3, align 8, !tbaa !5
  %9 = load i8, ptr %7, align 1, !tbaa !11
  %10 = sext i8 %9 to i32
  %11 = icmp ne i32 %10, 0
  br i1 %11, label %12, label %16

12:                                               ; preds = %6
  %13 = load i64, ptr %5, align 8, !tbaa !9
  %14 = load i64, ptr %4, align 8, !tbaa !9
  %15 = icmp ult i64 %13, %14
  br label %16

16:                                               ; preds = %12, %6
  %17 = phi i1 [ false, %6 ], [ %15, %12 ]
  br i1 %17, label %18, label %21

18:                                               ; preds = %16
  %19 = load i64, ptr %5, align 8, !tbaa !9
  %20 = add i64 %19, 1
  store i64 %20, ptr %5, align 8, !tbaa !9
  br label %6, !llvm.loop !12

21:                                               ; preds = %16
  %22 = load i64, ptr %5, align 8, !tbaa !9
  call void @llvm.lifetime.end.p0(i64 8, ptr %5) #2
  ret i64 %22
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { 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 #2 = { 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 = !{!"long", !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 norecurse nosync nounwind memory(read, inaccessiblemem: none) uwtable
define dso_local i64 @strnlen(ptr nocapture noundef readonly %0, i64 noundef %1) local_unnamed_addr #0 {
  %3 = load i8, ptr %0, align 1, !tbaa !5
  %4 = icmp ne i8 %3, 0
  %5 = icmp ne i64 %1, 0
  %6 = and i1 %4, %5
  br i1 %6, label %.lr.ph, label %._crit_edge

.lr.ph:                                           ; preds = %2, %.lr.ph
  %.06 = phi i64 [ %8, %.lr.ph ], [ 0, %2 ]
  %.045 = phi ptr [ %7, %.lr.ph ], [ %0, %2 ]
  %7 = getelementptr inbounds i8, ptr %.045, i64 1
  %8 = add nuw i64 %.06, 1
  %9 = load i8, ptr %7, align 1, !tbaa !5
  %10 = icmp ne i8 %9, 0
  %11 = icmp ult i64 %8, %1
  %12 = select i1 %10, i1 %11, i1 false
  br i1 %12, label %.lr.ph, label %._crit_edge, !llvm.loop !8

._crit_edge:                                      ; preds = %.lr.ph, %2
  %.0.lcssa = phi i64 [ 0, %2 ], [ %8, %.lr.ph ]
  ret i64 %.0.lcssa
}

attributes #0 = { nofree norecurse nosync nounwind memory(read, 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 = !{!"omnipotent char", !7, i64 0}
!7 = !{!"Simple C/C++ TBAA"}
!8 = distinct !{!8, !9}
!9 = !{!"llvm.loop.mustprogress"}


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