Optimize MDNode to coallocate the operand list immediately

after the MDNode in memory.  This eliminates the operands
pointer and saves a new[] per node.

Note that the code in DIDerivedType::replaceAllUsesWith is wrong
and quite scary.  A MDNode should not be RAUW'd with something
else: this changes all uses of the mdnode, which may not be debug
info related!  Debug info should use something non-mdnode for
declarations.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92321 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Analysis/DebugInfo.cpp

@@ -284,7 +284,7 @@ void DIDerivedType::replaceAllUsesWith(DIDescriptor &D) {
   if (getNode() != D.getNode()) {
     MDNode *Node = DbgNode;
     Node->replaceAllUsesWith(D.getNode());
-    delete Node;
+    Node->destroy();
   }
 }