Introduce SpecificBumpPtrAllocator, a wrapper for BumpPtrAllocator which allows

only a single type of object to be allocated. Use it to make VNInfo destruction
typesafe.

llvm-svn: 99919

llvm/lib/CodeGen/LiveStackAnalysis.cpp

@@ -36,7 +36,7 @@ void LiveStacks::getAnalysisUsage(AnalysisUsage &AU) const {
 
 void LiveStacks::releaseMemory() {
   // Release VNInfo memroy regions after all VNInfo objects are dtor'd.
-  VNInfoAllocator.Reset();
+  VNInfoAllocator.DestroyAll();
   S2IMap.clear();
   S2RCMap.clear();
 }