; LLVM IR from Dovyski/opengl-demos :: libs/glm-0.9.9.3/test/core/core_func_integer_find_msb.ll (Z4nlz1j)

; 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 nounwind uwtable
define dso_local noundef i32 @_Z4nlz1j(i32 noundef %0) #0 {
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  store i32 %0, ptr %3, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #2
  %6 = load i32, ptr %3, align 4, !tbaa !5
  %7 = icmp eq i32 %6, 0
  br i1 %7, label %8, label %9

8:                                                ; preds = %1
  store i32 32, ptr %2, align 4
  store i32 1, ptr %5, align 4
  br label %49

9:                                                ; preds = %1
  store i32 0, ptr %4, align 4, !tbaa !5
  %10 = load i32, ptr %3, align 4, !tbaa !5
  %11 = icmp ule i32 %10, 65535
  br i1 %11, label %12, label %17

12:                                               ; preds = %9
  %13 = load i32, ptr %4, align 4, !tbaa !5
  %14 = add nsw i32 %13, 16
  store i32 %14, ptr %4, align 4, !tbaa !5
  %15 = load i32, ptr %3, align 4, !tbaa !5
  %16 = shl i32 %15, 16
  store i32 %16, ptr %3, align 4, !tbaa !5
  br label %17

17:                                               ; preds = %12, %9
  %18 = load i32, ptr %3, align 4, !tbaa !5
  %19 = icmp ule i32 %18, 16777215
  br i1 %19, label %20, label %25

20:                                               ; preds = %17
  %21 = load i32, ptr %4, align 4, !tbaa !5
  %22 = add nsw i32 %21, 8
  store i32 %22, ptr %4, align 4, !tbaa !5
  %23 = load i32, ptr %3, align 4, !tbaa !5
  %24 = shl i32 %23, 8
  store i32 %24, ptr %3, align 4, !tbaa !5
  br label %25

25:                                               ; preds = %20, %17
  %26 = load i32, ptr %3, align 4, !tbaa !5
  %27 = icmp ule i32 %26, 268435455
  br i1 %27, label %28, label %33

28:                                               ; preds = %25
  %29 = load i32, ptr %4, align 4, !tbaa !5
  %30 = add nsw i32 %29, 4
  store i32 %30, ptr %4, align 4, !tbaa !5
  %31 = load i32, ptr %3, align 4, !tbaa !5
  %32 = shl i32 %31, 4
  store i32 %32, ptr %3, align 4, !tbaa !5
  br label %33

33:                                               ; preds = %28, %25
  %34 = load i32, ptr %3, align 4, !tbaa !5
  %35 = icmp ule i32 %34, 1073741823
  br i1 %35, label %36, label %41

36:                                               ; preds = %33
  %37 = load i32, ptr %4, align 4, !tbaa !5
  %38 = add nsw i32 %37, 2
  store i32 %38, ptr %4, align 4, !tbaa !5
  %39 = load i32, ptr %3, align 4, !tbaa !5
  %40 = shl i32 %39, 2
  store i32 %40, ptr %3, align 4, !tbaa !5
  br label %41

41:                                               ; preds = %36, %33
  %42 = load i32, ptr %3, align 4, !tbaa !5
  %43 = icmp ule i32 %42, 2147483647
  br i1 %43, label %44, label %47

44:                                               ; preds = %41
  %45 = load i32, ptr %4, align 4, !tbaa !5
  %46 = add nsw i32 %45, 1
  store i32 %46, ptr %4, align 4, !tbaa !5
  br label %47

47:                                               ; preds = %44, %41
  %48 = load i32, ptr %4, align 4, !tbaa !5
  store i32 %48, ptr %2, align 4
  store i32 1, ptr %5, align 4
  br label %49

49:                                               ; preds = %47, %8
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #2
  %50 = load i32, ptr %2, align 4
  ret i32 %50
}

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

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

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 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
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 @_Z4nlz1j(i32 noundef %0) local_unnamed_addr #0 {
  %2 = icmp eq i32 %0, 0
  br i1 %2, label %17, label %3

3:                                                ; preds = %1
  %4 = icmp ult i32 %0, 65536
  %5 = shl nuw i32 %0, 16
  %spec.select = select i1 %4, i32 %5, i32 %0
  %spec.select23 = select i1 %4, i32 16, i32 0
  %6 = icmp ult i32 %spec.select, 16777216
  %7 = or disjoint i32 %spec.select23, 8
  %8 = shl nuw i32 %spec.select, 8
  %.118 = select i1 %6, i32 %8, i32 %spec.select
  %.1 = select i1 %6, i32 %7, i32 %spec.select23
  %9 = icmp ult i32 %.118, 268435456
  %10 = or disjoint i32 %.1, 4
  %11 = shl nuw i32 %.118, 4
  %.219 = select i1 %9, i32 %11, i32 %.118
  %.2 = select i1 %9, i32 %10, i32 %.1
  %12 = icmp ult i32 %.219, 1073741824
  %13 = or disjoint i32 %.2, 2
  %14 = shl nuw i32 %.219, 2
  %.320 = select i1 %12, i32 %14, i32 %.219
  %.3 = select i1 %12, i32 %13, i32 %.2
  %15 = icmp sgt i32 %.320, -1
  %16 = zext i1 %15 to i32
  %.4 = add nuw nsw i32 %.3, %16
  br label %17

17:                                               ; preds = %1, %3
  %.021 = phi i32 [ %.4, %3 ], [ 32, %1 ]
  ret i32 %.021
}

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