Revert 'Fix a typo 'iff' => 'if''. iff is an abreviation of if and only if. See: http://en.wikipedia.org/wiki/If_and_only_if Commit 164767

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164768 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/IPO/GlobalOpt.cpp b/lib/Transforms/IPO/GlobalOpt.cpp
index bde6064..b888e95 100644
--- a/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/lib/Transforms/IPO/GlobalOpt.cpp
@@ -172,7 +172,7 @@
   return (AtomicOrdering)std::max(X, Y);
 }
 
-/// SafeToDestroyConstant - It is safe to destroy a constant if it is only used
+/// SafeToDestroyConstant - It is safe to destroy a constant iff it is only used
 /// by constants itself.  Note that constants cannot be cyclic, so this test is
 /// pretty easy to implement recursively.
 ///