; LLVM IR from JessonYue/LeetCodeLearning :: Array/zhuqiguang/c (StringU)

; 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 ptr @my_strcat(ptr noundef %0, ptr noundef %1) #0 {
  %3 = alloca ptr, align 8
  %4 = alloca ptr, align 8
  %5 = alloca ptr, align 8
  store ptr %0, ptr %4, align 8, !tbaa !5
  store ptr %1, ptr %5, align 8, !tbaa !5
  %6 = load ptr, ptr %4, align 8, !tbaa !5
  %7 = icmp eq ptr %6, null
  br i1 %7, label %11, label %8

8:                                                ; preds = %2
  %9 = load ptr, ptr %5, align 8, !tbaa !5
  %10 = icmp eq ptr %9, null
  br i1 %10, label %11, label %12

11:                                               ; preds = %8, %2
  store ptr null, ptr %3, align 8
  br label %33

12:                                               ; preds = %8
  br label %13

13:                                               ; preds = %18, %12
  %14 = load ptr, ptr %4, align 8, !tbaa !5
  %15 = load i8, ptr %14, align 1, !tbaa !9
  %16 = sext i8 %15 to i32
  %17 = icmp ne i32 %16, 0
  br i1 %17, label %18, label %21

18:                                               ; preds = %13
  %19 = load ptr, ptr %4, align 8, !tbaa !5
  %20 = getelementptr inbounds i8, ptr %19, i32 1
  store ptr %20, ptr %4, align 8, !tbaa !5
  br label %13, !llvm.loop !10

21:                                               ; preds = %13
  br label %22

22:                                               ; preds = %30, %21
  %23 = load ptr, ptr %5, align 8, !tbaa !5
  %24 = getelementptr inbounds i8, ptr %23, i32 1
  store ptr %24, ptr %5, align 8, !tbaa !5
  %25 = load i8, ptr %23, align 1, !tbaa !9
  %26 = load ptr, ptr %4, align 8, !tbaa !5
  %27 = getelementptr inbounds i8, ptr %26, i32 1
  store ptr %27, ptr %4, align 8, !tbaa !5
  store i8 %25, ptr %26, align 1, !tbaa !9
  %28 = sext i8 %25 to i32
  %29 = icmp ne i32 %28, 0
  br i1 %29, label %30, label %31

30:                                               ; preds = %22
  br label %22, !llvm.loop !12

31:                                               ; preds = %22
  %32 = load ptr, ptr %4, align 8, !tbaa !5
  store ptr %32, ptr %3, align 8
  br label %33

33:                                               ; preds = %31, %11
  %34 = load ptr, ptr %3, align 8
  ret ptr %34
}

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" }

!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 ptr @my_strcat(ptr noundef %0, ptr noundef readonly %1) local_unnamed_addr #0 {
  %3 = icmp eq ptr %0, null
  %4 = icmp eq ptr %1, null
  %or.cond = or i1 %3, %4
  br i1 %or.cond, label %.loopexit, label %.preheader13

.preheader13:                                     ; preds = %2, %.preheader13
  %.09 = phi ptr [ %6, %.preheader13 ], [ %0, %2 ]
  %5 = load i8, ptr %.09, align 1, !tbaa !5
  %.not = icmp eq i8 %5, 0
  %6 = getelementptr inbounds i8, ptr %.09, i64 1
  br i1 %.not, label %.preheader, label %.preheader13, !llvm.loop !8

.preheader:                                       ; preds = %.preheader13, %.preheader
  %.1 = phi ptr [ %9, %.preheader ], [ %.09, %.preheader13 ]
  %.0 = phi ptr [ %7, %.preheader ], [ %1, %.preheader13 ]
  %7 = getelementptr inbounds i8, ptr %.0, i64 1
  %8 = load i8, ptr %.0, align 1, !tbaa !5
  %9 = getelementptr inbounds i8, ptr %.1, i64 1
  store i8 %8, ptr %.1, align 1, !tbaa !5
  %.not12 = icmp eq i8 %8, 0
  br i1 %.not12, label %.loopexit, label %.preheader, !llvm.loop !10

.loopexit:                                        ; preds = %.preheader, %2
  %.010 = phi ptr [ null, %2 ], [ %9, %.preheader ]
  ret ptr %.010
}

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: GVNPass,GlobalOptPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass