; LLVM IR from JessonYue/LeetCodeLearning :: Array/caiweixiong/c (homework_str_test)

; 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 ptr @my_strcat(ptr noundef %0, ptr noundef %1) #1 {
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  %5 = alloca ptr, align 8
  %6 = alloca ptr, align 8
  %7 = alloca ptr, align 8
  store ptr %0, ptr %4, align 8, !tbaa !5
  store ptr %1, ptr %5, align 8, !tbaa !5
  %8 = load ptr, ptr %4, align 8, !tbaa !5
  %9 = icmp ne ptr %8, null
  br i1 %9, label %10, label %13

10:                                               ; preds = %2
  %11 = load ptr, ptr %5, align 8, !tbaa !5
  %12 = icmp ne ptr %11, null
  br i1 %12, label %14, label %13

13:                                               ; preds = %10, %2
  store ptr null, ptr %3, align 8
  br label %39

14:                                               ; preds = %10
  call void @llvm.lifetime.start.p0(i64 8, ptr %6) #2
  %15 = load ptr, ptr %4, align 8, !tbaa !5
  store ptr %15, ptr %6, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %7) #2
  %16 = load ptr, ptr %5, align 8, !tbaa !5
  store ptr %16, ptr %7, align 8, !tbaa !5
  br label %17

17:                                               ; preds = %22, %14
  %18 = load ptr, ptr %6, align 8, !tbaa !5
  %19 = load i8, ptr %18, align 1, !tbaa !9
  %20 = sext i8 %19 to i32
  %21 = icmp ne i32 %20, 0
  br i1 %21, label %22, label %25

22:                                               ; preds = %17
  %23 = load ptr, ptr %6, align 8, !tbaa !5
  %24 = getelementptr inbounds i8, ptr %23, i32 1
  store ptr %24, ptr %6, align 8, !tbaa !5
  br label %17, !llvm.loop !10

25:                                               ; preds = %17
  br label %26

26:                                               ; preds = %31, %25
  %27 = load ptr, ptr %7, align 8, !tbaa !5
  %28 = load i8, ptr %27, align 1, !tbaa !9
  %29 = sext i8 %28 to i32
  %30 = icmp ne i32 %29, 0
  br i1 %30, label %31, label %37

31:                                               ; preds = %26
  %32 = load ptr, ptr %7, align 8, !tbaa !5
  %33 = getelementptr inbounds i8, ptr %32, i32 1
  store ptr %33, ptr %7, align 8, !tbaa !5
  %34 = load i8, ptr %32, align 1, !tbaa !9
  %35 = load ptr, ptr %6, align 8, !tbaa !5
  %36 = getelementptr inbounds i8, ptr %35, i32 1
  store ptr %36, ptr %6, align 8, !tbaa !5
  store i8 %34, ptr %35, align 1, !tbaa !9
  br label %26, !llvm.loop !12

37:                                               ; preds = %26
  %38 = load ptr, ptr %4, align 8, !tbaa !5
  store ptr %38, ptr %3, align 8
  call void @llvm.lifetime.end.p0(i64 8, ptr %7) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %6) #2
  br label %39

39:                                               ; preds = %37, %13
  %40 = load ptr, ptr %3, align 8
  ret ptr %40
}

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 = !{!7, !7, i64 0}
!10 = distinct !{!10, !11}
!11 = !{!"llvm.loop.mustprogress"}
!12 = distinct !{!12, !11}


; 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(readwrite, inaccessiblemem: none) uwtable
define dso_local noundef ptr @my_strcat(ptr noundef %0, ptr noundef readonly %1) local_unnamed_addr #0 {
  %3 = icmp ne ptr %0, null
  %4 = icmp ne ptr %1, null
  %or.cond = and i1 %3, %4
  br i1 %or.cond, label %.preheader17, label %.loopexit

.preheader17:                                     ; preds = %2, %.preheader17
  %.012 = phi ptr [ %6, %.preheader17 ], [ %0, %2 ]
  %5 = load i8, ptr %.012, align 1, !tbaa !5
  %.not = icmp eq i8 %5, 0
  %6 = getelementptr inbounds i8, ptr %.012, i64 1
  br i1 %.not, label %.preheader, label %.preheader17, !llvm.loop !8

.preheader:                                       ; preds = %.preheader17
  %7 = load i8, ptr %1, align 1, !tbaa !5
  %.not1618 = icmp eq i8 %7, 0
  br i1 %.not1618, label %.loopexit, label %.lr.ph

.lr.ph:                                           ; preds = %.preheader, %.lr.ph
  %8 = phi i8 [ %11, %.lr.ph ], [ %7, %.preheader ]
  %.020 = phi ptr [ %9, %.lr.ph ], [ %1, %.preheader ]
  %.119 = phi ptr [ %10, %.lr.ph ], [ %.012, %.preheader ]
  %9 = getelementptr inbounds i8, ptr %.020, i64 1
  %10 = getelementptr inbounds i8, ptr %.119, i64 1
  store i8 %8, ptr %.119, align 1, !tbaa !5
  %11 = load i8, ptr %9, align 1, !tbaa !5
  %.not16 = icmp eq i8 %11, 0
  br i1 %.not16, label %.loopexit, label %.lr.ph, !llvm.loop !10

.loopexit:                                        ; preds = %.lr.ph, %.preheader, %2
  %.013 = phi ptr [ null, %2 ], [ %0, %.preheader ], [ %0, %.lr.ph ]
  ret ptr %.013
}

attributes #0 = { nofree norecurse nosync nounwind memory(readwrite, 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"}
!10 = distinct !{!10, !9}


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