1 files changed, 16 insertions, 3 deletions
diff --git a/llvm/lib/Analysis/AliasSetTracker.cpp b/llvm/lib/Analysis/AliasSetTracker.cpp
index 377db8a569f..51a61e9e2d9 100644
--- a/llvm/lib/Analysis/AliasSetTracker.cpp
+++ b/llvm/lib/Analysis/AliasSetTracker.cpp
@@ -256,9 +256,22 @@ Instruction* AliasSet::getUniqueInstruction() {
   if (AliasAny)
     // May have collapses alias set
     return nullptr;
-  if (size() != 0)
-    // Can't track source of pointer, might be many instruction
-    return nullptr;
+  if (begin() != end()) {
+    if (!UnknownInsts.empty())
+      // Another instruction found
+      return nullptr;
+    if (std::next(begin()) != end())
+      // Another instruction found
+      return nullptr;
+    Value *Addr = begin()->getValue();
+    assert(!Addr->user_empty() &&
+           "where's the instruction which added this pointer?");
+    if (std::next(Addr->user_begin()) != Addr->user_end())
+      // Another instruction found -- this is really restrictive
+      // TODO: generalize!
+      return nullptr;
+    return cast<Instruction>(*(Addr->user_begin()));
+  }
   if (1 != UnknownInsts.size())
     return nullptr;
   return cast<Instruction>(UnknownInsts[0]);