; LLVM IR from JessonYue/LeetCodeLearning :: Array/chenjiaming/面试题10.01合并排序的数组 (sort)

; 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 @comp(ptr noundef, ptr noundef) #0

; Function Attrs: nounwind uwtable
define dso_local void @merge(ptr noundef %0, i32 noundef %1, i32 noundef %2, ptr noundef %3, i32 noundef %4, i32 noundef %5) #0 {
  %7 = alloca ptr, align 8
  %8 = alloca i32, align 4
  %9 = alloca i32, align 4
  %10 = alloca ptr, align 8
  %11 = alloca i32, align 4
  %12 = alloca i32, align 4
  %13 = alloca i32, align 4
  store ptr %0, ptr %7, align 8, !tbaa !5
  store i32 %1, ptr %8, align 4, !tbaa !9
  store i32 %2, ptr %9, align 4, !tbaa !9
  store ptr %3, ptr %10, align 8, !tbaa !5
  store i32 %4, ptr %11, align 4, !tbaa !9
  store i32 %5, ptr %12, align 4, !tbaa !9
  call void @llvm.lifetime.start.p0(i64 4, ptr %13) #3
  store i32 0, ptr %13, align 4, !tbaa !9
  br label %14

14:                                               ; preds = %31, %6
  %15 = load i32, ptr %13, align 4, !tbaa !9
  %16 = load i32, ptr %12, align 4, !tbaa !9
  %17 = icmp slt i32 %15, %16
  br i1 %17, label %19, label %18

18:                                               ; preds = %14
  call void @llvm.lifetime.end.p0(i64 4, ptr %13) #3
  br label %34

19:                                               ; preds = %14
  %20 = load ptr, ptr %10, align 8, !tbaa !5
  %21 = load i32, ptr %13, align 4, !tbaa !9
  %22 = sext i32 %21 to i64
  %23 = getelementptr inbounds i32, ptr %20, i64 %22
  %24 = load i32, ptr %23, align 4, !tbaa !9
  %25 = load ptr, ptr %7, align 8, !tbaa !5
  %26 = load i32, ptr %9, align 4, !tbaa !9
  %27 = load i32, ptr %13, align 4, !tbaa !9
  %28 = add nsw i32 %26, %27
  %29 = sext i32 %28 to i64
  %30 = getelementptr inbounds i32, ptr %25, i64 %29
  store i32 %24, ptr %30, align 4, !tbaa !9
  br label %31

31:                                               ; preds = %19
  %32 = load i32, ptr %13, align 4, !tbaa !9
  %33 = add nsw i32 %32, 1
  store i32 %33, ptr %13, align 4, !tbaa !9
  br label %14, !llvm.loop !11

34:                                               ; preds = %18
  %35 = load ptr, ptr %7, align 8, !tbaa !5
  %36 = load i32, ptr %9, align 4, !tbaa !9
  %37 = load i32, ptr %12, align 4, !tbaa !9
  %38 = add nsw i32 %36, %37
  %39 = sext i32 %38 to i64
  call void @qsort(ptr noundef %35, i64 noundef %39, i64 noundef 4, ptr noundef @comp)
  ret void
}

; 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

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 @comp(ptr noundef, ptr noundef) #0

; Function Attrs: nofree nounwind uwtable
define dso_local void @merge(ptr noundef %0, i32 noundef %1, i32 noundef %2, ptr nocapture noundef readonly %3, i32 noundef %4, i32 noundef %5) local_unnamed_addr #1 {
  %7 = ptrtoint ptr %3 to i64
  %8 = ptrtoint ptr %0 to i64
  %9 = icmp sgt i32 %5, 0
  br i1 %9, label %.lr.ph.preheader, label %._crit_edge

.lr.ph.preheader:                                 ; preds = %6
  %10 = sext i32 %2 to i64
  %wide.trip.count = zext nneg i32 %5 to i64
  %invariant.gep = getelementptr i32, ptr %0, i64 %10
  %min.iters.check = icmp ult i32 %5, 12
  br i1 %min.iters.check, label %.lr.ph.preheader14, label %vector.memcheck

.lr.ph.preheader14:                               ; preds = %middle.block, %vector.memcheck, %.lr.ph.preheader
  %indvars.iv.ph = phi i64 [ 0, %vector.memcheck ], [ 0, %.lr.ph.preheader ], [ %n.vec, %middle.block ]
  %xtraiter = and i64 %wide.trip.count, 3
  %lcmp.mod.not = icmp eq i64 %xtraiter, 0
  br i1 %lcmp.mod.not, label %.lr.ph.prol.loopexit, label %.lr.ph.prol

.lr.ph.prol:                                      ; preds = %.lr.ph.preheader14, %.lr.ph.prol
  %indvars.iv.prol = phi i64 [ %indvars.iv.next.prol, %.lr.ph.prol ], [ %indvars.iv.ph, %.lr.ph.preheader14 ]
  %prol.iter = phi i64 [ %prol.iter.next, %.lr.ph.prol ], [ 0, %.lr.ph.preheader14 ]
  %11 = getelementptr inbounds i32, ptr %3, i64 %indvars.iv.prol
  %12 = load i32, ptr %11, align 4, !tbaa !5
  %gep.prol = getelementptr i32, ptr %invariant.gep, i64 %indvars.iv.prol
  store i32 %12, ptr %gep.prol, align 4, !tbaa !5
  %indvars.iv.next.prol = add nuw nsw i64 %indvars.iv.prol, 1
  %prol.iter.next = add i64 %prol.iter, 1
  %prol.iter.cmp.not = icmp eq i64 %prol.iter.next, %xtraiter
  br i1 %prol.iter.cmp.not, label %.lr.ph.prol.loopexit, label %.lr.ph.prol, !llvm.loop !9

.lr.ph.prol.loopexit:                             ; preds = %.lr.ph.prol, %.lr.ph.preheader14
  %indvars.iv.unr = phi i64 [ %indvars.iv.ph, %.lr.ph.preheader14 ], [ %indvars.iv.next.prol, %.lr.ph.prol ]
  %13 = sub nsw i64 %indvars.iv.ph, %wide.trip.count
  %14 = icmp ugt i64 %13, -4
  br i1 %14, label %._crit_edge, label %.lr.ph

vector.memcheck:                                  ; preds = %.lr.ph.preheader
  %15 = shl nsw i64 %10, 2
  %16 = add i64 %15, %8
  %17 = sub i64 %16, %7
  %diff.check = icmp ult i64 %17, 32
  br i1 %diff.check, label %.lr.ph.preheader14, label %vector.ph

vector.ph:                                        ; preds = %vector.memcheck
  %n.vec = and i64 %wide.trip.count, 2147483640
  br label %vector.body

vector.body:                                      ; preds = %vector.body, %vector.ph
  %index = phi i64 [ 0, %vector.ph ], [ %index.next, %vector.body ]
  %18 = getelementptr inbounds i32, ptr %3, i64 %index
  %19 = getelementptr inbounds i8, ptr %18, i64 16
  %wide.load = load <4 x i32>, ptr %18, align 4, !tbaa !5
  %wide.load13 = load <4 x i32>, ptr %19, align 4, !tbaa !5
  %20 = getelementptr i32, ptr %invariant.gep, i64 %index
  %21 = getelementptr i8, ptr %20, i64 16
  store <4 x i32> %wide.load, ptr %20, align 4, !tbaa !5
  store <4 x i32> %wide.load13, ptr %21, align 4, !tbaa !5
  %index.next = add nuw i64 %index, 8
  %22 = icmp eq i64 %index.next, %n.vec
  br i1 %22, label %middle.block, label %vector.body, !llvm.loop !11

middle.block:                                     ; preds = %vector.body
  %cmp.n = icmp eq i64 %n.vec, %wide.trip.count
  br i1 %cmp.n, label %._crit_edge, label %.lr.ph.preheader14

._crit_edge:                                      ; preds = %.lr.ph.prol.loopexit, %.lr.ph, %middle.block, %6
  %23 = add nsw i32 %5, %2
  %24 = sext i32 %23 to i64
  tail call void @qsort(ptr noundef %0, i64 noundef %24, i64 noundef 4, ptr noundef nonnull @comp) #3
  ret void

.lr.ph:                                           ; preds = %.lr.ph.prol.loopexit, %.lr.ph
  %indvars.iv = phi i64 [ %indvars.iv.next.3, %.lr.ph ], [ %indvars.iv.unr, %.lr.ph.prol.loopexit ]
  %25 = getelementptr inbounds i32, ptr %3, i64 %indvars.iv
  %26 = load i32, ptr %25, align 4, !tbaa !5
  %gep = getelementptr i32, ptr %invariant.gep, i64 %indvars.iv
  store i32 %26, ptr %gep, align 4, !tbaa !5
  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
  %27 = getelementptr inbounds i32, ptr %3, i64 %indvars.iv.next
  %28 = load i32, ptr %27, align 4, !tbaa !5
  %gep.1 = getelementptr i32, ptr %invariant.gep, i64 %indvars.iv.next
  store i32 %28, ptr %gep.1, align 4, !tbaa !5
  %indvars.iv.next.1 = add nuw nsw i64 %indvars.iv, 2
  %29 = getelementptr inbounds i32, ptr %3, i64 %indvars.iv.next.1
  %30 = load i32, ptr %29, align 4, !tbaa !5
  %gep.2 = getelementptr i32, ptr %invariant.gep, i64 %indvars.iv.next.1
  store i32 %30, ptr %gep.2, align 4, !tbaa !5
  %indvars.iv.next.2 = add nuw nsw i64 %indvars.iv, 3
  %31 = getelementptr inbounds i32, ptr %3, i64 %indvars.iv.next.2
  %32 = load i32, ptr %31, align 4, !tbaa !5
  %gep.3 = getelementptr i32, ptr %invariant.gep, i64 %indvars.iv.next.2
  store i32 %32, ptr %gep.3, align 4, !tbaa !5
  %indvars.iv.next.3 = add nuw nsw i64 %indvars.iv, 4
  %exitcond.not.3 = icmp eq i64 %indvars.iv.next.3, %wide.trip.count
  br i1 %exitcond.not.3, label %._crit_edge, label %.lr.ph, !llvm.loop !15
}

; 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.unroll.disable"}
!11 = distinct !{!11, !12, !13, !14}
!12 = !{!"llvm.loop.mustprogress"}
!13 = !{!"llvm.loop.isvectorized", i32 1}
!14 = !{!"llvm.loop.unroll.runtime.disable"}
!15 = distinct !{!15, !12, !13}


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