; LLVM IR from Dovyski/opengl-demos :: libs/glm-0.9.9.3/test/core/core_func_integer_find_msb.ll (Z4nlz2j)

; 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: mustprogress nounwind uwtable
define dso_local noundef i32 @_Z4nlz2j(i32 noundef %0) #1 {
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  %6 = alloca i32, align 4
  store i32 %0, ptr %3, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #2
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #2
  store i32 32, ptr %5, align 4, !tbaa !5
  %7 = load i32, ptr %3, align 4, !tbaa !5
  %8 = lshr i32 %7, 16
  store i32 %8, ptr %4, align 4, !tbaa !5
  %9 = load i32, ptr %4, align 4, !tbaa !5
  %10 = icmp ne i32 %9, 0
  br i1 %10, label %11, label %15

11:                                               ; preds = %1
  %12 = load i32, ptr %5, align 4, !tbaa !5
  %13 = sub nsw i32 %12, 16
  store i32 %13, ptr %5, align 4, !tbaa !5
  %14 = load i32, ptr %4, align 4, !tbaa !5
  store i32 %14, ptr %3, align 4, !tbaa !5
  br label %15

15:                                               ; preds = %11, %1
  %16 = load i32, ptr %3, align 4, !tbaa !5
  %17 = lshr i32 %16, 8
  store i32 %17, ptr %4, align 4, !tbaa !5
  %18 = load i32, ptr %4, align 4, !tbaa !5
  %19 = icmp ne i32 %18, 0
  br i1 %19, label %20, label %24

20:                                               ; preds = %15
  %21 = load i32, ptr %5, align 4, !tbaa !5
  %22 = sub nsw i32 %21, 8
  store i32 %22, ptr %5, align 4, !tbaa !5
  %23 = load i32, ptr %4, align 4, !tbaa !5
  store i32 %23, ptr %3, align 4, !tbaa !5
  br label %24

24:                                               ; preds = %20, %15
  %25 = load i32, ptr %3, align 4, !tbaa !5
  %26 = lshr i32 %25, 4
  store i32 %26, ptr %4, align 4, !tbaa !5
  %27 = load i32, ptr %4, align 4, !tbaa !5
  %28 = icmp ne i32 %27, 0
  br i1 %28, label %29, label %33

29:                                               ; preds = %24
  %30 = load i32, ptr %5, align 4, !tbaa !5
  %31 = sub nsw i32 %30, 4
  store i32 %31, ptr %5, align 4, !tbaa !5
  %32 = load i32, ptr %4, align 4, !tbaa !5
  store i32 %32, ptr %3, align 4, !tbaa !5
  br label %33

33:                                               ; preds = %29, %24
  %34 = load i32, ptr %3, align 4, !tbaa !5
  %35 = lshr i32 %34, 2
  store i32 %35, ptr %4, align 4, !tbaa !5
  %36 = load i32, ptr %4, align 4, !tbaa !5
  %37 = icmp ne i32 %36, 0
  br i1 %37, label %38, label %42

38:                                               ; preds = %33
  %39 = load i32, ptr %5, align 4, !tbaa !5
  %40 = sub nsw i32 %39, 2
  store i32 %40, ptr %5, align 4, !tbaa !5
  %41 = load i32, ptr %4, align 4, !tbaa !5
  store i32 %41, ptr %3, align 4, !tbaa !5
  br label %42

42:                                               ; preds = %38, %33
  %43 = load i32, ptr %3, align 4, !tbaa !5
  %44 = lshr i32 %43, 1
  store i32 %44, ptr %4, align 4, !tbaa !5
  %45 = load i32, ptr %4, align 4, !tbaa !5
  %46 = icmp ne i32 %45, 0
  br i1 %46, label %47, label %50

47:                                               ; preds = %42
  %48 = load i32, ptr %5, align 4, !tbaa !5
  %49 = sub nsw i32 %48, 2
  store i32 %49, ptr %2, align 4
  store i32 1, ptr %6, align 4
  br label %54

50:                                               ; preds = %42
  %51 = load i32, ptr %5, align 4, !tbaa !5
  %52 = load i32, ptr %3, align 4, !tbaa !5
  %53 = sub i32 %51, %52
  store i32 %53, ptr %2, align 4
  store i32 1, ptr %6, align 4
  br label %54

54:                                               ; preds = %50, %47
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #2
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #2
  %55 = load i32, ptr %2, align 4
  ret i32 %55
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { 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 #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 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}


; 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 nofree norecurse nosync nounwind willreturn memory(none) uwtable
define dso_local noundef i32 @_Z4nlz2j(i32 noundef %0) local_unnamed_addr #0 {
  %.not = icmp ult i32 %0, 65536
  %2 = lshr i32 %0, 16
  %spec.select = select i1 %.not, i32 %0, i32 %2
  %spec.select35 = select i1 %.not, i32 32, i32 16
  %.not31 = icmp ult i32 %spec.select, 256
  %3 = lshr i32 %spec.select, 8
  %4 = add nsw i32 %spec.select35, -8
  %.123 = select i1 %.not31, i32 %spec.select, i32 %3
  %.1 = select i1 %.not31, i32 %spec.select35, i32 %4
  %.not32 = icmp ult i32 %.123, 16
  %5 = lshr i32 %.123, 4
  %6 = add nsw i32 %.1, -4
  %.224 = select i1 %.not32, i32 %.123, i32 %5
  %.2 = select i1 %.not32, i32 %.1, i32 %6
  %.not33 = icmp ult i32 %.224, 4
  %7 = lshr i32 %.224, 2
  %8 = add nsw i32 %.2, -2
  %.325 = select i1 %.not33, i32 %.224, i32 %7
  %.3 = select i1 %.not33, i32 %.2, i32 %8
  %.not34 = icmp ult i32 %.325, 2
  %9 = sub nsw i32 0, %.325
  %.026.p = select i1 %.not34, i32 %9, i32 -2
  %.026 = add nsw i32 %.026.p, %.3
  ret i32 %.026
}

attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn memory(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)"}


; Effective O3 passes: CorrelatedValuePropagationPass,EarlyCSEPass,GlobalOptPass,IPSCCPPass,InferFunctionAttrsPass,InstCombinePass,PostOrderFunctionAttrsPass,ReassociatePass,SROAPass,SimplifyCFGPass