From 3013ea1b63f6f214ec814a16dd65d93e899c376a Mon Sep 17 00:00:00 2001
From: "Duncan P. N. Exon Smith" <dexonsmith@apple.com>
Date: Sun, 11 Sep 2016 22:11:37 +0000
Subject: [PATCH] Analysis: Only allow the move-constructor for IVUsers

Force IVUsers to be moved instead of copied, properly update Parent
pointers in IVStrideUse when IVUsers is moved, and make sure we have
move constructors available in iplist and ilist.

I came across this in a WIP patch that deleted the copy constructors
from ilist.  I was surprised to find that IVUsersAnalysis couldn't be
registered in the new pass manager.

It's not clear to me whether IVUsers was getting moved only when empty,
but if it was being moved when it was non-empty then this fixes a
pointer invalidation bug and should give some sort of speedup.  Note
that the bugfix would be necessary even for a copy constructor.

llvm-svn: 281181
---
 llvm/include/llvm/ADT/ilist.h        | 30 +++++++++++++++++++++++++++-
 llvm/include/llvm/Analysis/IVUsers.h | 11 ++++++++++
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/llvm/include/llvm/ADT/ilist.h b/llvm/include/llvm/ADT/ilist.h
index 8f5e8810a1ea..0f7b37b3765f 100644
--- a/llvm/include/llvm/ADT/ilist.h
+++ b/llvm/include/llvm/ADT/ilist.h
@@ -161,6 +161,9 @@ template <class IntrusiveListT, class TraitsT>
 class iplist_impl : public TraitsT, IntrusiveListT {
   typedef IntrusiveListT base_list_type;
 
+protected:
+  typedef iplist_impl iplist_impl_type;
+
 public:
   typedef typename base_list_type::pointer pointer;
   typedef typename base_list_type::const_pointer const_pointer;
@@ -192,6 +195,13 @@ private:
 
 public:
   iplist_impl() = default;
+  iplist_impl(iplist_impl &&X)
+      : TraitsT(std::move(X)), IntrusiveListT(std::move(X)) {}
+  iplist_impl &operator=(iplist_impl &&X) {
+    *static_cast<TraitsT *>(this) = std::move(X);
+    *static_cast<IntrusiveListT *>(this) = std::move(X);
+    return *this;
+  }
   ~iplist_impl() { clear(); }
 
   // Miscellaneous inspection routines.
@@ -367,7 +377,19 @@ public:
 /// there for a description of what's available.
 template <class T, class... Options>
 class iplist
-    : public iplist_impl<simple_ilist<T, Options...>, ilist_traits<T>> {};
+    : public iplist_impl<simple_ilist<T, Options...>, ilist_traits<T>> {
+  typedef typename iplist::iplist_impl_type iplist_impl_type;
+
+public:
+  iplist() = default;
+  iplist(iplist &&X) : iplist_impl_type(std::move(X)) {}
+  iplist(const iplist &X) = delete;
+  iplist &operator=(iplist &&X) {
+    *static_cast<iplist_impl_type *>(this) = std::move(X);
+    return *this;
+  }
+  iplist &operator=(const iplist &X) = delete;
+};
 
 /// An intrusive list with ownership and callbacks specified/controlled by
 /// ilist_traits, with API that is unsafe for polymorphic types.
@@ -395,6 +417,12 @@ public:
     insert(this->begin(), first, last);
   }
 
+  ilist(ilist &&X) : base_list_type(std::move(X)) {}
+  ilist &operator=(ilist &&X) {
+    *static_cast<base_list_type *>(this) = std::move(X);
+    return *this;
+  }
+
   // bring hidden functions into scope
   using base_list_type::insert;
   using base_list_type::push_front;
diff --git a/llvm/include/llvm/Analysis/IVUsers.h b/llvm/include/llvm/Analysis/IVUsers.h
index b208c027e45c..e8777e0b38ae 100644
--- a/llvm/include/llvm/Analysis/IVUsers.h
+++ b/llvm/include/llvm/Analysis/IVUsers.h
@@ -111,6 +111,17 @@ public:
   IVUsers(Loop *L, AssumptionCache *AC, LoopInfo *LI, DominatorTree *DT,
           ScalarEvolution *SE);
 
+  IVUsers(IVUsers &&X)
+      : L(std::move(X.L)), AC(std::move(X.AC)), DT(std::move(X.DT)),
+        SE(std::move(X.SE)), Processed(std::move(X.Processed)),
+        IVUses(std::move(X.IVUses)), EphValues(std::move(X.EphValues)) {
+    for (IVStrideUse &U : IVUses)
+      U.Parent = this;
+  }
+  IVUsers(const IVUsers &) = delete;
+  IVUsers &operator=(IVUsers &&) = delete;
+  IVUsers &operator=(const IVUsers &) = delete;
+
   Loop *getLoop() const { return L; }
 
   /// AddUsersIfInteresting - Inspect the specified Instruction.  If it is a