"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

1 files changed, 4 insertions, 2 deletions

diff --git a/include/llvm/CodeGen/MachineFunction.h b/include/llvm/CodeGen/MachineFunction.h
index 689e4357b1..1371f1d0cd 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);