diff --git a/lib/Transforms/Scalar/LICM.cpp b/lib/Transforms/Scalar/LICM.cpp
index 669afa33ac9..ede3bd9dde6 100644
--- a/lib/Transforms/Scalar/LICM.cpp
+++ b/lib/Transforms/Scalar/LICM.cpp
@@ -218,7 +218,9 @@ namespace {
 
 LoopPass *llvm::createLICMPass() { return new LICM(); }
 
-/// Hoist expressions out of the specified loop...
+/// Hoist expressions out of the specified loop. Note, alias info for inner
+/// loop is not preserved so it is not a good idea to run LICM multiple 
+/// times on one loop.
 ///
 bool LICM::runOnLoop(Loop *L, LPPassManager &LPM) {
   Changed = false;