convert LoopInfo.h and GraphWriter.h to use raw_ostream


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79836 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/PostRASchedulerList.cpp b/lib/CodeGen/PostRASchedulerList.cpp
index 320e6b4..5042415 100644
--- a/lib/CodeGen/PostRASchedulerList.cpp
+++ b/lib/CodeGen/PostRASchedulerList.cpp
@@ -765,9 +765,9 @@
   
 #ifndef NDEBUG
   if (SuccSU->NumPredsLeft < 0) {
-    cerr << "*** Scheduling failed! ***\n";
+    errs() << "*** Scheduling failed! ***\n";
     SuccSU->dump(this);
-    cerr << " has been released too many times!\n";
+    errs() << " has been released too many times!\n";
     llvm_unreachable(0);
   }
 #endif