Livestacks really does preserve everything.

llvm-svn: 56476
diff --git a/llvm/lib/CodeGen/LiveStackAnalysis.cpp b/llvm/lib/CodeGen/LiveStackAnalysis.cpp
index 0670570..2baf699 100644
--- a/llvm/lib/CodeGen/LiveStackAnalysis.cpp
+++ b/llvm/lib/CodeGen/LiveStackAnalysis.cpp
@@ -25,8 +25,7 @@
 static RegisterPass<LiveStacks> X("livestacks", "Live Stack Slot Analysis");
 
 void LiveStacks::getAnalysisUsage(AnalysisUsage &AU) const {
-  AU.addPreservedID(MachineLoopInfoID);
-  AU.addPreservedID(MachineDominatorsID);
+  AU.setPreservesAll();
   MachineFunctionPass::getAnalysisUsage(AU);
 }