[NFC][LoopIdiom] Adjust FIXME to be self-explanatory

llvm-svn: 374670
diff --git a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
index 46c8cfb..116bdd7 100644
--- a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
@@ -2202,7 +2202,7 @@
                                       CurLoop->getHeader())
              << L;
     });
-    return false; // FIXME
+    return false; // FIXME: support non-simple loads.
   }
 
   LLVM_DEBUG(dbgs() << "Recognized bcmp idiom\n");