; LLVM IR from HarshCasper/NeoAlgo :: C-Plus-Plus/cp/friends_pairing.ll (Z14friendsPairingi)

; 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: mustprogress uwtable
define dso_local noundef i32 @_Z14friendsPairingi(i32 noundef %0) #0 {
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  store i32 %0, ptr %3, align 4, !tbaa !5
  %6 = load i32, ptr %3, align 4, !tbaa !5
  %7 = icmp eq i32 %6, 0
  br i1 %7, label %11, label %8

8:                                                ; preds = %1
  %9 = load i32, ptr %3, align 4, !tbaa !5
  %10 = icmp eq i32 %9, 1
  br i1 %10, label %11, label %12

11:                                               ; preds = %8, %1
  store i32 1, ptr %2, align 4
  br label %30

12:                                               ; preds = %8
  %13 = load i32, ptr %3, align 4, !tbaa !5
  %14 = icmp eq i32 %13, 2
  br i1 %14, label %15, label %16

15:                                               ; preds = %12
  store i32 2, ptr %2, align 4
  br label %30

16:                                               ; preds = %12
  call void @llvm.lifetime.start.p0(i64 4, ptr %4) #2
  %17 = call noundef i32 @_Z14friendsPairingi(i32 noundef 1)
  %18 = load i32, ptr %3, align 4, !tbaa !5
  %19 = sub nsw i32 %18, 1
  %20 = call noundef i32 @_Z14friendsPairingi(i32 noundef %19)
  %21 = mul nsw i32 %17, %20
  store i32 %21, ptr %4, align 4, !tbaa !5
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #2
  %22 = call noundef i32 @_Z14friendsPairingi(i32 noundef 2)
  %23 = load i32, ptr %3, align 4, !tbaa !5
  %24 = sub nsw i32 %23, 2
  %25 = call noundef i32 @_Z14friendsPairingi(i32 noundef %24)
  %26 = mul nsw i32 %22, %25
  store i32 %26, ptr %5, align 4, !tbaa !5
  %27 = load i32, ptr %4, align 4, !tbaa !5
  %28 = load i32, ptr %5, align 4, !tbaa !5
  %29 = add nsw i32 %27, %28
  store i32 %29, ptr %2, align 4
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #2
  call void @llvm.lifetime.end.p0(i64 4, ptr %4) #2
  br label %30

30:                                               ; preds = %16, %15, %11
  %31 = load i32, ptr %2, align 4
  ret i32 %31
}

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #1

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #1

attributes #0 = { mustprogress 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 #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
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 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C++ TBAA"}


; 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 nosync nounwind willreturn memory(none) uwtable
define dso_local noundef i32 @_Z14friendsPairingi(i32 noundef %0) local_unnamed_addr #0 {
  %or.cond = icmp ult i32 %0, 2
  br i1 %or.cond, label %common.ret10, label %2

2:                                                ; preds = %1
  %3 = icmp eq i32 %0, 2
  br i1 %3, label %common.ret10, label %4

common.ret10:                                     ; preds = %2, %1, %4
  %common.ret10.op = phi i32 [ %10, %4 ], [ 1, %1 ], [ 2, %2 ]
  ret i32 %common.ret10.op

4:                                                ; preds = %2
  %5 = add nsw i32 %0, -1
  %6 = tail call noundef i32 @_Z14friendsPairingi(i32 noundef %5)
  %7 = add nsw i32 %0, -2
  %8 = tail call noundef i32 @_Z14friendsPairingi(i32 noundef %7)
  %9 = shl nsw i32 %8, 1
  %10 = add nsw i32 %9, %6
  br label %common.ret10
}

attributes #0 = { mustprogress nofree nosync nounwind willreturn memory(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)"}


; Effective O3 passes: EarlyCSEPass,GlobalOptPass,IPSCCPPass,InferFunctionAttrsPass,InlinerPass,InstCombinePass,PostOrderFunctionAttrsPass,ReassociatePass,SROAPass,SimplifyCFGPass,TailCallElimPass