diff --git a/llvm/lib/Analysis/AliasAnalysis.cpp b/llvm/lib/Analysis/AliasAnalysis.cpp
index 263dd48..a9d4610 100644
--- a/llvm/lib/Analysis/AliasAnalysis.cpp
+++ b/llvm/lib/Analysis/AliasAnalysis.cpp
@@ -142,6 +142,8 @@
 
   if (onlyReadsMemory(MRB))
     Result = ModRefInfo(Result & MRI_Ref);
+  else if (doesNotReadMemory(MRB))
+    Result = ModRefInfo(Result & MRI_Mod);
 
   if (onlyAccessesArgPointees(MRB)) {
     bool DoesAlias = false;
@@ -207,6 +209,8 @@
   // from CS1 reading memory written by CS2.
   if (onlyReadsMemory(CS1B))
     Result = ModRefInfo(Result & MRI_Ref);
+  else if (doesNotReadMemory(CS1B))
+    Result = ModRefInfo(Result & MRI_Mod);
 
   // If CS2 only access memory through arguments, accumulate the mod/ref
   // information from CS1's references to the memory referenced by