Livestacks really does preserve everything.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56476 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveStackAnalysis.cpp b/lib/CodeGen/LiveStackAnalysis.cpp
index 0670570..2baf699 100644
--- a/lib/CodeGen/LiveStackAnalysis.cpp
+++ b/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);
 }