From c7f6b8c5d40e17bf43fd3a1549d7d89c9da735e1 Mon Sep 17 00:00:00 2001
From: Gabor Greif <ggreif@gmail.com>
Date: Wed, 4 Mar 2009 06:57:48 +0000
Subject: [PATCH] "Ghostify" embedded sentinels. This is a real win in all
 cases because less bytes are allocated and subobject construction is gone.
 For reference how it works, see BasicBlock.h. Btw. it is very assuring to see
 that somebody has invented this ilist-embedded sentinel technique before me
 :-)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66026 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/CodeGen/MachineBasicBlock.h | 6 ++++--
 include/llvm/CodeGen/MachineFunction.h   | 6 ++++--
 include/llvm/CodeGen/SelectionDAG.h      | 7 ++-----
 3 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/include/llvm/CodeGen/MachineBasicBlock.h b/include/llvm/CodeGen/MachineBasicBlock.h
index 54ac47008f2..5a9f3991f2c 100644
--- a/include/llvm/CodeGen/MachineBasicBlock.h
+++ b/include/llvm/CodeGen/MachineBasicBlock.h
@@ -26,14 +26,16 @@ class MachineFunction;
 template <>
 struct ilist_traits<MachineInstr> : public ilist_default_traits<MachineInstr> {
 private:
-  mutable MachineInstr Sentinel;
+  mutable ilist_node<MachineInstr> Sentinel;
 
   // this is only set by the MachineBasicBlock owning the LiveList
   friend class MachineBasicBlock;
   MachineBasicBlock* Parent;
 
 public:
-  MachineInstr *createSentinel() const { return &Sentinel; }
+  MachineInstr *createSentinel() const {
+    return static_cast<MachineInstr*>(&Sentinel);
+  }
   void destroySentinel(MachineInstr *) const {}
 
   void addNodeToList(MachineInstr* N);
diff --git a/include/llvm/CodeGen/MachineFunction.h b/include/llvm/CodeGen/MachineFunction.h
index 689e4357b1d..1371f1d0cdf 100644
--- a/include/llvm/CodeGen/MachineFunction.h
+++ b/include/llvm/CodeGen/MachineFunction.h
@@ -37,9 +37,11 @@ class TargetMachine;
 template <>
 struct ilist_traits<MachineBasicBlock>
     : public ilist_default_traits<MachineBasicBlock> {
-  mutable MachineBasicBlock Sentinel;
+  mutable ilist_node<MachineBasicBlock> Sentinel;
 public:
-  MachineBasicBlock *createSentinel() const { return &Sentinel; }
+  MachineBasicBlock *createSentinel() const {
+    return static_cast<MachineBasicBlock*>(&Sentinel);
+  }
   void destroySentinel(MachineBasicBlock *) const {}
 
   void addNodeToList(MachineBasicBlock* MBB);
diff --git a/include/llvm/CodeGen/SelectionDAG.h b/include/llvm/CodeGen/SelectionDAG.h
index 9ecba590dd4..fe89fe05460 100644
--- a/include/llvm/CodeGen/SelectionDAG.h
+++ b/include/llvm/CodeGen/SelectionDAG.h
@@ -39,13 +39,10 @@ class FunctionLoweringInfo;
 
 template<> struct ilist_traits<SDNode> : public ilist_default_traits<SDNode> {
 private:
-  mutable SDNode Sentinel;
+  mutable ilist_node<SDNode> Sentinel;
 public:
-  ilist_traits() : Sentinel(ISD::DELETED_NODE, DebugLoc::getUnknownLoc(),
-                            SDVTList()) {}
-
   SDNode *createSentinel() const {
-    return &Sentinel;
+    return static_cast<SDNode*>(&Sentinel);
   }
   static void destroySentinel(SDNode *) {}
 
-- 
2.34.1