; LLVM IR from DimitrisJim/leetcode_solutions :: C/Algorithms (561)

; 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
declare dso_local i32 @cmpi(ptr noundef, ptr noundef) #0

; 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

; Function Attrs: nounwind uwtable
define dso_local i32 @arrayPairSum(ptr noundef %0, i32 noundef %1) #0 {
  %3 = alloca ptr, align 8
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  store ptr %0, ptr %3, align 8, !tbaa !5
  store i32 %1, ptr %4, align 4, !tbaa !9
  %6 = load ptr, ptr %3, align 8, !tbaa !5
  %7 = load i32, ptr %4, align 4, !tbaa !9
  %8 = sext i32 %7 to i64
  call void @qsort(ptr noundef %6, i64 noundef %8, i64 noundef 4, ptr noundef @cmpi)
  call void @llvm.lifetime.start.p0(i64 4, ptr %5) #3
  store i32 0, ptr %5, align 4, !tbaa !9
  br label %9

9:                                                ; preds = %13, %2
  %10 = load i32, ptr %4, align 4, !tbaa !9
  %11 = add nsw i32 %10, -1
  store i32 %11, ptr %4, align 4, !tbaa !9
  %12 = icmp ne i32 %10, 0
  br i1 %12, label %13, label %22

13:                                               ; preds = %9
  %14 = load ptr, ptr %3, align 8, !tbaa !5
  %15 = load i32, ptr %4, align 4, !tbaa !9
  %16 = add nsw i32 %15, -1
  store i32 %16, ptr %4, align 4, !tbaa !9
  %17 = sext i32 %16 to i64
  %18 = getelementptr inbounds i32, ptr %14, i64 %17
  %19 = load i32, ptr %18, align 4, !tbaa !9
  %20 = load i32, ptr %5, align 4, !tbaa !9
  %21 = add i32 %20, %19
  store i32 %21, ptr %5, align 4, !tbaa !9
  br label %9, !llvm.loop !11

22:                                               ; preds = %9
  %23 = load i32, ptr %5, align 4, !tbaa !9
  call void @llvm.lifetime.end.p0(i64 4, ptr %5) #3
  ret i32 %23
}

declare void @qsort(ptr noundef, i64 noundef, i64 noundef, ptr noundef) #2

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" }
attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #2 = { "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 #3 = { 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 = !{!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: nounwind uwtable
declare dso_local i32 @cmpi(ptr noundef, ptr noundef) #0

; Function Attrs: nofree nounwind uwtable
define dso_local i32 @arrayPairSum(ptr noundef %0, i32 noundef %1) local_unnamed_addr #1 {
  %3 = sext i32 %1 to i64
  tail call void @qsort(ptr noundef %0, i64 noundef %3, i64 noundef 4, ptr noundef nonnull @cmpi) #3
  %.not7 = icmp eq i32 %1, 0
  br i1 %.not7, label %._crit_edge, label %.lr.ph.preheader

.lr.ph.preheader:                                 ; preds = %2
  %4 = add nsw i64 %3, -2
  %5 = lshr i64 %4, 1
  %6 = add nuw i64 %5, 1
  %xtraiter = and i64 %6, 7
  %7 = icmp ult i64 %4, 14
  br i1 %7, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph.preheader.new

.lr.ph.preheader.new:                             ; preds = %.lr.ph.preheader
  %unroll_iter = and i64 %6, -8
  %invariant.gep = getelementptr i8, ptr %0, i64 -8
  %invariant.gep14 = getelementptr i8, ptr %0, i64 -16
  %invariant.gep16 = getelementptr i8, ptr %0, i64 -24
  %invariant.gep18 = getelementptr i8, ptr %0, i64 -32
  %invariant.gep20 = getelementptr i8, ptr %0, i64 -40
  %invariant.gep22 = getelementptr i8, ptr %0, i64 -48
  %invariant.gep24 = getelementptr i8, ptr %0, i64 -56
  br label %.lr.ph

.lr.ph:                                           ; preds = %.lr.ph, %.lr.ph.preheader.new
  %indvars.iv = phi i64 [ %3, %.lr.ph.preheader.new ], [ %indvars.iv.next.7, %.lr.ph ]
  %.09 = phi i32 [ 0, %.lr.ph.preheader.new ], [ %24, %.lr.ph ]
  %niter = phi i64 [ 0, %.lr.ph.preheader.new ], [ %niter.next.7, %.lr.ph ]
  %gep = getelementptr i32, ptr %invariant.gep, i64 %indvars.iv
  %8 = load i32, ptr %gep, align 4, !tbaa !5
  %9 = add i32 %8, %.09
  %gep15 = getelementptr i32, ptr %invariant.gep14, i64 %indvars.iv
  %10 = load i32, ptr %gep15, align 4, !tbaa !5
  %11 = add i32 %10, %9
  %gep17 = getelementptr i32, ptr %invariant.gep16, i64 %indvars.iv
  %12 = load i32, ptr %gep17, align 4, !tbaa !5
  %13 = add i32 %12, %11
  %gep19 = getelementptr i32, ptr %invariant.gep18, i64 %indvars.iv
  %14 = load i32, ptr %gep19, align 4, !tbaa !5
  %15 = add i32 %14, %13
  %gep21 = getelementptr i32, ptr %invariant.gep20, i64 %indvars.iv
  %16 = load i32, ptr %gep21, align 4, !tbaa !5
  %17 = add i32 %16, %15
  %gep23 = getelementptr i32, ptr %invariant.gep22, i64 %indvars.iv
  %18 = load i32, ptr %gep23, align 4, !tbaa !5
  %19 = add i32 %18, %17
  %gep25 = getelementptr i32, ptr %invariant.gep24, i64 %indvars.iv
  %20 = load i32, ptr %gep25, align 4, !tbaa !5
  %21 = add i32 %20, %19
  %indvars.iv.next.7 = add nsw i64 %indvars.iv, -16
  %22 = getelementptr inbounds i32, ptr %0, i64 %indvars.iv.next.7
  %23 = load i32, ptr %22, align 4, !tbaa !5
  %24 = add i32 %23, %21
  %niter.next.7 = add i64 %niter, 8
  %niter.ncmp.7 = icmp eq i64 %niter.next.7, %unroll_iter
  br i1 %niter.ncmp.7, label %._crit_edge.loopexit.unr-lcssa, label %.lr.ph, !llvm.loop !9

._crit_edge.loopexit.unr-lcssa:                   ; preds = %.lr.ph, %.lr.ph.preheader
  %.lcssa.ph = phi i32 [ poison, %.lr.ph.preheader ], [ %24, %.lr.ph ]
  %indvars.iv.unr = phi i64 [ %3, %.lr.ph.preheader ], [ %indvars.iv.next.7, %.lr.ph ]
  %.09.unr = phi i32 [ 0, %.lr.ph.preheader ], [ %24, %.lr.ph ]
  %lcmp.mod.not = icmp eq i64 %xtraiter, 0
  br i1 %lcmp.mod.not, label %._crit_edge, label %.lr.ph.epil

.lr.ph.epil:                                      ; preds = %._crit_edge.loopexit.unr-lcssa, %.lr.ph.epil
  %indvars.iv.epil = phi i64 [ %indvars.iv.next.epil, %.lr.ph.epil ], [ %indvars.iv.unr, %._crit_edge.loopexit.unr-lcssa ]
  %.09.epil = phi i32 [ %27, %.lr.ph.epil ], [ %.09.unr, %._crit_edge.loopexit.unr-lcssa ]
  %epil.iter = phi i64 [ %epil.iter.next, %.lr.ph.epil ], [ 0, %._crit_edge.loopexit.unr-lcssa ]
  %indvars.iv.next.epil = add nsw i64 %indvars.iv.epil, -2
  %25 = getelementptr inbounds i32, ptr %0, i64 %indvars.iv.next.epil
  %26 = load i32, ptr %25, align 4, !tbaa !5
  %27 = add i32 %26, %.09.epil
  %epil.iter.next = add i64 %epil.iter, 1
  %epil.iter.cmp.not = icmp eq i64 %epil.iter.next, %xtraiter
  br i1 %epil.iter.cmp.not, label %._crit_edge, label %.lr.ph.epil, !llvm.loop !11

._crit_edge:                                      ; preds = %._crit_edge.loopexit.unr-lcssa, %.lr.ph.epil, %2
  %.0.lcssa = phi i32 [ 0, %2 ], [ %.lcssa.ph, %._crit_edge.loopexit.unr-lcssa ], [ %27, %.lr.ph.epil ]
  ret i32 %.0.lcssa
}

; Function Attrs: nofree
declare void @qsort(ptr noundef, i64 noundef, i64 noundef, ptr nocapture noundef) local_unnamed_addr #2

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" }
attributes #1 = { nofree 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 = { nofree "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 #3 = { 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/C++ TBAA"}
!9 = distinct !{!9, !10}
!10 = !{!"llvm.loop.mustprogress"}
!11 = distinct !{!11, !12}
!12 = !{!"llvm.loop.unroll.disable"}


; Effective O3 passes: GVNPass,GlobalOptPass,IndVarSimplifyPass,InferFunctionAttrsPass,InstCombinePass,InstSimplifyPass,JumpThreadingPass,LCSSAPass,LICMPass,LoopRotatePass,LoopSimplifyPass,LoopUnrollPass,PostOrderFunctionAttrsPass,ReassociatePass,SROAPass,SimplifyCFGPass,TailCallElimPass