Fix -Asserts warning.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81909 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index 34d55ec..6296e93 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -637,13 +637,14 @@
   return false;
 }
 
-
+#ifndef NDEBUG
 static void printRegName(unsigned reg, const TargetRegisterInfo* tri_) {
   if (TargetRegisterInfo::isPhysicalRegister(reg))
     errs() << tri_->getName(reg);
   else
     errs() << "%reg" << reg;
 }
+#endif
 
 void LiveIntervals::handleVirtualRegisterDef(MachineBasicBlock *mbb,
                                              MachineBasicBlock::iterator mi,