1 files changed, 9 insertions, 1 deletions
diff --git a/llvm/lib/Analysis/AliasSetTracker.cpp b/llvm/lib/Analysis/AliasSetTracker.cpp
index 91b889116dfa..debdd328ce53 100644
--- a/llvm/lib/Analysis/AliasSetTracker.cpp
+++ b/llvm/lib/Analysis/AliasSetTracker.cpp
@@ -348,8 +348,16 @@ AliasSet &AliasSetTracker::getAliasSetFor(const MemoryLocation &MemLoc) {
     // due to a quirk of alias analysis behavior. Since alias(undef, undef)
     // is NoAlias, mergeAliasSetsForPointer(undef, ...) will not find the
     // the right set for undef, even if it exists.
-    if (Entry.updateSizeAndAAInfo(Size, AAInfo))
+    if (Entry.updateSizeAndAAInfo(Size, AAInfo)) {
       mergeAliasSetsForPointer(Pointer, Size, AAInfo, MustAliasAll);
+
+      // For MustAlias sets, also update Size/AAInfo of the representative
+      // pointer.
+      AliasSet &AS = *Entry.getAliasSet(*this);
+      if (AS.isMustAlias())
+        if (AliasSet::PointerRec *P = AS.getSomePointer())
+          P->updateSizeAndAAInfo(Size, AAInfo);
+    }
     // Return the set!
     return *Entry.getAliasSet(*this)->getForwardedTarget(*this);
   }