; LLVM IR from JessonYue/LeetCodeLearning :: Array/wuchao/other/7-16 c实现string函数 (StringUtils)

; 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 i32 @strchr(ptr noundef %0, i8 noundef signext %1) #1 {
  %3 = alloca i32, align 4
  %4 = alloca ptr, align 8
  %5 = alloca i8, align 1
  %6 = alloca i32, align 4
  %7 = alloca i32, align 4
  store ptr %0, ptr %4, align 8, !tbaa !5
  store i8 %1, ptr %5, align 1, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %6) #2
  store i32 0, ptr %6, align 4, !tbaa !10
  br label %8

8:                                                ; preds = %28, %2
  %9 = load ptr, ptr %4, align 8, !tbaa !5
  %10 = load i32, ptr %6, align 4, !tbaa !10
  %11 = sext i32 %10 to i64
  %12 = getelementptr inbounds i8, ptr %9, i64 %11
  %13 = load i8, ptr %12, align 1, !tbaa !9
  %14 = sext i8 %13 to i32
  %15 = icmp ne i32 %14, 0
  br i1 %15, label %16, label %31

16:                                               ; preds = %8
  %17 = load ptr, ptr %4, align 8, !tbaa !5
  %18 = load i32, ptr %6, align 4, !tbaa !10
  %19 = sext i32 %18 to i64
  %20 = getelementptr inbounds i8, ptr %17, i64 %19
  %21 = load i8, ptr %20, align 1, !tbaa !9
  %22 = sext i8 %21 to i32
  %23 = load i8, ptr %5, align 1, !tbaa !9
  %24 = sext i8 %23 to i32
  %25 = icmp eq i32 %22, %24
  br i1 %25, label %26, label %28

26:                                               ; preds = %16
  %27 = load i32, ptr %6, align 4, !tbaa !10
  store i32 %27, ptr %3, align 4
  store i32 1, ptr %7, align 4
  br label %32

28:                                               ; preds = %16
  %29 = load i32, ptr %6, align 4, !tbaa !10
  %30 = add nsw i32 %29, 1
  store i32 %30, ptr %6, align 4, !tbaa !10
  br label %8, !llvm.loop !12

31:                                               ; preds = %8
  store i32 0, ptr %7, align 4
  br label %32

32:                                               ; preds = %31, %26
  call void @llvm.lifetime.end.p0(i64 4, ptr %6) #2
  %33 = load i32, ptr %7, align 4
  switch i32 %33, label %36 [
    i32 0, label %34
    i32 1, label %34
  ]

34:                                               ; preds = %32, %32
  %35 = load i32, ptr %3, align 4
  ret i32 %35

36:                                               ; preds = %32
  unreachable
}

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 = !{!11, !11, i64 0}
!11 = !{!"int", !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 norecurse nosync nounwind memory(argmem: read) uwtable
define dso_local i32 @strchr(ptr nocapture noundef readonly %0, i8 noundef signext %1) local_unnamed_addr #0 {
  br label %3

3:                                                ; preds = %3, %2
  %indvars.iv = phi i64 [ %indvars.iv.next, %3 ], [ 0, %2 ]
  %4 = getelementptr inbounds i8, ptr %0, i64 %indvars.iv
  %5 = load i8, ptr %4, align 1, !tbaa !5
  %.not = icmp eq i8 %5, 0
  %6 = icmp eq i8 %5, %1
  %or.cond = or i1 %.not, %6
  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
  br i1 %or.cond, label %7, label %3, !llvm.loop !8

7:                                                ; preds = %3
  %8 = trunc nuw nsw i64 %indvars.iv to i32
  ret i32 %8
}

attributes #0 = { nofree norecurse nosync 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" }

!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: EarlyCSEPass,GVNPass,GlobalOptPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,LCSSAPass,LoopRotatePass,LoopUnrollPass,PostOrderFunctionAttrsPass,SROAPass,SimplifyCFGPass