Release build: guard dump functions with "ifndef NDEBUG"

No functional change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163344 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCExpr.cpp b/lib/MC/MCExpr.cpp
index 2d1cadd..b196659 100644
--- a/lib/MC/MCExpr.cpp
+++ b/lib/MC/MCExpr.cpp
@@ -136,10 +136,12 @@
   llvm_unreachable("Invalid expression kind!");
 }
 
+#ifndef NDEBUG
 void MCExpr::dump() const {
   print(dbgs());
   dbgs() << '\n';
 }
+#endif
 
 /* *** */