diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp
index 0b131bc76b6..16bb53f63b7 100644
--- a/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/lib/Analysis/BasicAliasAnalysis.cpp
@@ -14,7 +14,9 @@
 // FIXME: This could be extended for a very simple form of mod/ref information.
 // If a pointer is locally allocated (either malloc or alloca) and never passed
 // into a call or stored to memory, then we know that calls will not mod/ref the
-// memory.  This can be important for tailcallelim.
+// memory.  This can be important for tailcallelim, and can support CSE of loads
+// and dead store elimination across calls.  This is particularly important for
+// stack allocated arrays.
 //
 //===----------------------------------------------------------------------===//