; LLVM IR from kaynewbie/algorithm :: algorithm/LeetCode/Easy (length-of-last-word)

; 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 @lengthOfLastWord(ptr noundef %0) #0 {
  %2 = alloca i32, align 4
  %3 = alloca ptr, align 8
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  %6 = alloca i32, align 4
  %7 = alloca i32, align 4
  store ptr %0, ptr %3, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #3
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #3
  store i32 0, ptr %5, align 4, !tbaa !9
  %8 = load ptr, ptr %3, align 8, !tbaa !5
  %9 = call i64 @strlen(ptr noundef %8) #4
  %10 = trunc i64 %9 to i32
  store i32 %10, ptr %4, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %6) #3
  %11 = load i32, ptr %4, align 4, !tbaa !9
  %12 = sub nsw i32 %11, 1
  store i32 %12, ptr %6, align 4, !tbaa !9
  br label %13

13:                                               ; preds = %42, %1
  %14 = load i32, ptr %6, align 4, !tbaa !9
  %15 = icmp sge i32 %14, 0
  br i1 %15, label %17, label %16

16:                                               ; preds = %13
  store i32 2, ptr %7, align 4
  br label %45

17:                                               ; preds = %13
  %18 = load ptr, ptr %3, align 8, !tbaa !5
  %19 = load i32, ptr %6, align 4, !tbaa !9
  %20 = sext i32 %19 to i64
  %21 = getelementptr inbounds i8, ptr %18, i64 %20
  %22 = load i8, ptr %21, align 1, !tbaa !11
  %23 = sext i8 %22 to i32
  %24 = icmp eq i32 %23, 32
  br i1 %24, label %25, label %30

25:                                               ; preds = %17
  %26 = load i32, ptr %5, align 4, !tbaa !9
  %27 = icmp ne i32 %26, 0
  br i1 %27, label %28, label %30

28:                                               ; preds = %25
  %29 = load i32, ptr %5, align 4, !tbaa !9
  store i32 %29, ptr %2, align 4
  store i32 1, ptr %7, align 4
  br label %45

30:                                               ; preds = %25, %17
  %31 = load ptr, ptr %3, align 8, !tbaa !5
  %32 = load i32, ptr %6, align 4, !tbaa !9
  %33 = sext i32 %32 to i64
  %34 = getelementptr inbounds i8, ptr %31, i64 %33
  %35 = load i8, ptr %34, align 1, !tbaa !11
  %36 = sext i8 %35 to i32
  %37 = icmp ne i32 %36, 32
  br i1 %37, label %38, label %41

38:                                               ; preds = %30
  %39 = load i32, ptr %5, align 4, !tbaa !9
  %40 = add nsw i32 %39, 1
  store i32 %40, ptr %5, align 4, !tbaa !9
  br label %41

41:                                               ; preds = %38, %30
  br label %42

42:                                               ; preds = %41
  %43 = load i32, ptr %6, align 4, !tbaa !9
  %44 = add nsw i32 %43, -1
  store i32 %44, ptr %6, align 4, !tbaa !9
  br label %13, !llvm.loop !12

45:                                               ; preds = %28, %16
  call void @llvm.lifetime.end.p0(i64 4, ptr %6) #3
  %46 = load i32, ptr %7, align 4
  switch i32 %46, label %49 [
    i32 2, label %47
  ]

47:                                               ; preds = %45
  %48 = load i32, ptr %5, align 4, !tbaa !9
  store i32 %48, ptr %2, align 4
  store i32 1, ptr %7, align 4
  br label %49

49:                                               ; preds = %47, %45
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #3
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #3
  %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: 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 @lengthOfLastWord(ptr nocapture noundef readonly %0) local_unnamed_addr #0 {
  %2 = tail call i64 @strlen(ptr noundef nonnull dereferenceable(1) %0) #2
  %3 = trunc i64 %2 to i32
  %4 = icmp slt i32 %3, 1
  br i1 %4, label %.critedge, label %.lr.ph.preheader

.lr.ph.preheader:                                 ; preds = %1
  %5 = and i64 %2, 2147483647
  br label %.lr.ph

.lr.ph:                                           ; preds = %.lr.ph.preheader, %10
  %indvars.iv = phi i64 [ %5, %.lr.ph.preheader ], [ %indvars.iv.next, %10 ]
  %.01519 = phi i32 [ 0, %.lr.ph.preheader ], [ %spec.select, %10 ]
  %indvars.iv.next = add nsw i64 %indvars.iv, -1
  %6 = getelementptr inbounds i8, ptr %0, i64 %indvars.iv.next
  %7 = load i8, ptr %6, align 1, !tbaa !5
  %8 = icmp eq i8 %7, 32
  %9 = icmp ne i32 %.01519, 0
  %or.cond = select i1 %8, i1 %9, i1 false
  br i1 %or.cond, label %.critedge, label %10

10:                                               ; preds = %.lr.ph
  %not. = xor i1 %8, true
  %11 = zext i1 %not. to i32
  %spec.select = add nuw nsw i32 %.01519, %11
  %12 = icmp ult i64 %indvars.iv, 2
  br i1 %12, label %.critedge, label %.lr.ph, !llvm.loop !8

.critedge:                                        ; preds = %.lr.ph, %10, %1
  %.015.lcssa = phi i32 [ 0, %1 ], [ %spec.select, %10 ], [ %.01519, %.lr.ph ]
  ret i32 %.015.lcssa
}

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

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 = { 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}
!9 = !{!"llvm.loop.mustprogress"}


; Effective O3 passes: CorrelatedValuePropagationPass,EarlyCSEPass,GlobalOptPass,IPSCCPPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,ReassociatePass,SROAPass,SimplifyCFGPass,TailCallElimPass