; LLVM IR from ritikbanger/Hacktoberfest2022-DSA :: 05. Searching/order-agnostic-search.ll (Z11desc_searchPii)

; 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: mustprogress nounwind uwtable
define dso_local noundef i32 @_Z11desc_searchPii(ptr noundef %0, i32 noundef %1) #1 {
  %3 = alloca i32, align 4
  %4 = alloca ptr, align 8
  %5 = alloca i32, align 4
  %6 = alloca i32, align 4
  %7 = alloca i32, align 4
  %8 = alloca i32, align 4
  %9 = alloca i32, align 4
  %10 = alloca i32, align 4
  store ptr %0, ptr %4, align 8, !tbaa !5
  store i32 %1, ptr %5, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %6) #2
  store i32 2, ptr %6, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %7) #2
  store i32 0, ptr %7, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %8) #2
  %11 = load i32, ptr %5, align 4, !tbaa !9
  %12 = sub nsw i32 %11, 1
  store i32 %12, ptr %8, align 4, !tbaa !9
  br label %13

13:                                               ; preds = %51, %2
  %14 = load i32, ptr %7, align 4, !tbaa !9
  %15 = load i32, ptr %8, align 4, !tbaa !9
  %16 = icmp sle i32 %14, %15
  br i1 %16, label %17, label %52

17:                                               ; preds = %13
  call void @llvm.lifetime.start.p0(i64 4, ptr %9) #2
  %18 = load i32, ptr %7, align 4, !tbaa !9
  %19 = load i32, ptr %8, align 4, !tbaa !9
  %20 = load i32, ptr %7, align 4, !tbaa !9
  %21 = sub nsw i32 %19, %20
  %22 = sdiv i32 %21, 2
  %23 = add nsw i32 %18, %22
  store i32 %23, ptr %9, align 4, !tbaa !9
  %24 = load i32, ptr %6, align 4, !tbaa !9
  %25 = load ptr, ptr %4, align 8, !tbaa !5
  %26 = load i32, ptr %9, align 4, !tbaa !9
  %27 = sext i32 %26 to i64
  %28 = getelementptr inbounds i32, ptr %25, i64 %27
  %29 = load i32, ptr %28, align 4, !tbaa !9
  %30 = icmp eq i32 %24, %29
  br i1 %30, label %31, label %33

31:                                               ; preds = %17
  %32 = load i32, ptr %9, align 4, !tbaa !9
  store i32 %32, ptr %3, align 4
  store i32 1, ptr %10, align 4
  br label %49

33:                                               ; preds = %17
  %34 = load i32, ptr %6, align 4, !tbaa !9
  %35 = load ptr, ptr %4, align 8, !tbaa !5
  %36 = load i32, ptr %9, align 4, !tbaa !9
  %37 = sext i32 %36 to i64
  %38 = getelementptr inbounds i32, ptr %35, i64 %37
  %39 = load i32, ptr %38, align 4, !tbaa !9
  %40 = icmp slt i32 %34, %39
  br i1 %40, label %41, label %44

41:                                               ; preds = %33
  %42 = load i32, ptr %9, align 4, !tbaa !9
  %43 = add nsw i32 %42, 1
  store i32 %43, ptr %7, align 4, !tbaa !9
  br label %47

44:                                               ; preds = %33
  %45 = load i32, ptr %9, align 4, !tbaa !9
  %46 = sub nsw i32 %45, 1
  store i32 %46, ptr %8, align 4, !tbaa !9
  br label %47

47:                                               ; preds = %44, %41
  br label %48

48:                                               ; preds = %47
  store i32 0, ptr %10, align 4
  br label %49

49:                                               ; preds = %48, %31
  call void @llvm.lifetime.end.p0(i64 4, ptr %9) #2
  %50 = load i32, ptr %10, align 4
  switch i32 %50, label %53 [
    i32 0, label %51
  ]

51:                                               ; preds = %49
  br label %13, !llvm.loop !11

52:                                               ; preds = %13
  store i32 -1, ptr %3, align 4
  store i32 1, ptr %10, align 4
  br label %53

53:                                               ; preds = %52, %49
  call void @llvm.lifetime.end.p0(i64 4, ptr %8) #2
  call void @llvm.lifetime.end.p0(i64 4, ptr %7) #2
  call void @llvm.lifetime.end.p0(i64 4, ptr %6) #2
  %54 = load i32, ptr %3, align 4
  ret i32 %54
}

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #1 = { mustprogress 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++ TBAA"}
!9 = !{!10, !10, i64 0}
!10 = !{!"int", !7, i64 0}
!11 = distinct !{!11, !12}
!12 = !{!"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: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: read) uwtable
define dso_local noundef i32 @_Z11desc_searchPii(ptr nocapture noundef readonly %0, i32 noundef %1) local_unnamed_addr #0 {
  %.not28 = icmp slt i32 %1, 1
  br i1 %.not28, label %.thread, label %.lr.ph.preheader

.lr.ph.preheader:                                 ; preds = %2
  %3 = add nsw i32 %1, -1
  br label %.lr.ph

.lr.ph:                                           ; preds = %.lr.ph.preheader, %10
  %.01730 = phi i32 [ %.118, %10 ], [ %3, %.lr.ph.preheader ]
  %.02029 = phi i32 [ %.121, %10 ], [ 0, %.lr.ph.preheader ]
  %4 = sub nsw i32 %.01730, %.02029
  %5 = sdiv i32 %4, 2
  %6 = add nsw i32 %5, %.02029
  %7 = sext i32 %6 to i64
  %8 = getelementptr inbounds i32, ptr %0, i64 %7
  %9 = load i32, ptr %8, align 4, !tbaa !5
  %.not24 = icmp eq i32 %9, 2
  br i1 %.not24, label %.thread, label %10

10:                                               ; preds = %.lr.ph
  %11 = icmp sgt i32 %9, 2
  %12 = add nsw i32 %6, 1
  %13 = add nsw i32 %6, -1
  %.121 = select i1 %11, i32 %12, i32 %.02029
  %.118 = select i1 %11, i32 %.01730, i32 %13
  %.not = icmp sgt i32 %.121, %.118
  br i1 %.not, label %.thread, label %.lr.ph, !llvm.loop !9

.thread:                                          ; preds = %10, %.lr.ph, %2
  %.2 = phi i32 [ -1, %2 ], [ %6, %.lr.ph ], [ -1, %10 ]
  ret i32 %.2
}

attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn 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 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}
!9 = distinct !{!9, !10}
!10 = !{!"llvm.loop.mustprogress"}


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