Eliminate PromoteMemoryToRegisterID; just use addPreserved("mem2reg")
instead, as an example of what this looks like.

llvm-svn: 110478
diff --git a/llvm/lib/Transforms/Utils/LowerInvoke.cpp b/llvm/lib/Transforms/Utils/LowerInvoke.cpp
index f239a99..6ba5650 100644
--- a/llvm/lib/Transforms/Utils/LowerInvoke.cpp
+++ b/llvm/lib/Transforms/Utils/LowerInvoke.cpp
@@ -85,7 +85,7 @@
 
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
       // This is a cluster of orthogonal Transforms
-      AU.addPreservedID(PromoteMemoryToRegisterID);
+      AU.addPreserved("mem2reg");
       AU.addPreservedID(LowerSwitchID);
     }