; 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: 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_strstr(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
  %8 = alloca i32, align 4
  store ptr %0, ptr %4, align 8, !tbaa !5
  store ptr %1, ptr %5, align 8, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 8, ptr %6) #2
  call void @llvm.lifetime.start.p0(i64 8, ptr %7) #2
  br label %9

9:                                                ; preds = %33, %2
  %10 = load ptr, ptr %4, align 8, !tbaa !5
  %11 = load i8, ptr %10, align 1, !tbaa !9
  %12 = icmp ne i8 %11, 0
  br i1 %12, label %13, label %36

13:                                               ; preds = %9
  %14 = load ptr, ptr %4, align 8, !tbaa !5
  store ptr %14, ptr %6, align 8, !tbaa !5
  %15 = load ptr, ptr %5, align 8, !tbaa !5
  store ptr %15, ptr %7, align 8, !tbaa !5
  br label %16

16:                                               ; preds = %32, %13
  %17 = load ptr, ptr %6, align 8, !tbaa !5
  %18 = getelementptr inbounds i8, ptr %17, i32 1
  store ptr %18, ptr %6, align 8, !tbaa !5
  %19 = load i8, ptr %17, align 1, !tbaa !9
  %20 = sext i8 %19 to i32
  %21 = load ptr, ptr %7, align 8, !tbaa !5
  %22 = getelementptr inbounds i8, ptr %21, i32 1
  store ptr %22, ptr %7, align 8, !tbaa !5
  %23 = load i8, ptr %21, align 1, !tbaa !9
  %24 = sext i8 %23 to i32
  %25 = icmp eq i32 %20, %24
  br i1 %25, label %26, label %33

26:                                               ; preds = %16
  %27 = load ptr, ptr %7, align 8, !tbaa !5
  %28 = load i8, ptr %27, align 1, !tbaa !9
  %29 = icmp ne i8 %28, 0
  br i1 %29, label %32, label %30

30:                                               ; preds = %26
  %31 = load ptr, ptr %4, align 8, !tbaa !5
  store ptr %31, ptr %3, align 8
  store i32 1, ptr %8, align 4
  br label %37

32:                                               ; preds = %26
  br label %16, !llvm.loop !10

33:                                               ; preds = %16
  %34 = load ptr, ptr %4, align 8, !tbaa !5
  %35 = getelementptr inbounds i8, ptr %34, i32 1
  store ptr %35, ptr %4, align 8, !tbaa !5
  br label %9, !llvm.loop !12

36:                                               ; preds = %9
  store ptr null, ptr %3, align 8
  store i32 1, ptr %8, align 4
  br label %37

37:                                               ; preds = %36, %30
  call void @llvm.lifetime.end.p0(i64 8, ptr %7) #2
  call void @llvm.lifetime.end.p0(i64 8, ptr %6) #2
  %38 = load ptr, ptr %3, align 8
  ret ptr %38
}

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(read, inaccessiblemem: none) uwtable
define dso_local noundef ptr @my_strstr(ptr noundef readonly %0, ptr nocapture noundef readonly %1) local_unnamed_addr #0 {
  %3 = load i8, ptr %0, align 1, !tbaa !5
  %.not15 = icmp eq i8 %3, 0
  br i1 %.not15, label %.loopexit, label %.preheader.preheader

.preheader.preheader:                             ; preds = %2
  %.pre.pre = load i8, ptr %1, align 1, !tbaa !5
  br label %.preheader

.preheader:                                       ; preds = %.preheader.preheader, %12
  %.01116 = phi ptr [ %13, %12 ], [ %0, %.preheader.preheader ]
  br label %4

4:                                                ; preds = %.preheader, %8
  %5 = phi i8 [ %11, %8 ], [ %.pre.pre, %.preheader ]
  %.09 = phi ptr [ %10, %8 ], [ %.01116, %.preheader ]
  %.0 = phi ptr [ %9, %8 ], [ %1, %.preheader ]
  %6 = load i8, ptr %.09, align 1, !tbaa !5
  %7 = icmp eq i8 %6, %5
  br i1 %7, label %8, label %12

8:                                                ; preds = %4
  %9 = getelementptr inbounds i8, ptr %.0, i64 1
  %10 = getelementptr inbounds i8, ptr %.09, i64 1
  %11 = load i8, ptr %9, align 1, !tbaa !5
  %.not12 = icmp eq i8 %11, 0
  br i1 %.not12, label %.loopexit, label %4, !llvm.loop !8

12:                                               ; preds = %4
  %13 = getelementptr inbounds i8, ptr %.01116, i64 1
  %14 = load i8, ptr %13, align 1, !tbaa !5
  %.not = icmp eq i8 %14, 0
  br i1 %.not, label %.loopexit, label %.preheader, !llvm.loop !10

.loopexit:                                        ; preds = %12, %8, %2
  %.010 = phi ptr [ null, %2 ], [ %.01116, %8 ], [ null, %12 ]
  ret ptr %.010
}

attributes #0 = { nofree norecurse nosync nounwind memory(read, 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,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass