Add comment to emphasize that the while body is empty.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66115 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/CondPropagate.cpp b/lib/Transforms/Scalar/CondPropagate.cpp
index 7d5e581..45bc629 100644
--- a/lib/Transforms/Scalar/CondPropagate.cpp
+++ b/lib/Transforms/Scalar/CondPropagate.cpp
@@ -153,7 +153,7 @@
     return;
   BasicBlock::iterator BBI = BB->begin();
   BasicBlock::iterator BBE = BB->end();
-  while (BBI != BBE && isa<DbgInfoIntrinsic>(++BBI)) ;
+  while (BBI != BBE && isa<DbgInfoIntrinsic>(++BBI)) /* empty */;
   if (&*BBI != BI)
     return;
 
@@ -192,7 +192,7 @@
     return;
   BasicBlock::iterator BBI = BB->begin();
   BasicBlock::iterator BBE = BB->end();
-  while (BBI != BBE && isa<DbgInfoIntrinsic>(++BBI)) ;
+  while (BBI != BBE && isa<DbgInfoIntrinsic>(++BBI)) /* empty */;
   if (&*BBI != SI)
     return;