1 files changed, 14 insertions, 4 deletions
diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp
index 233a36d2bc5..f3460c49422 100644
--- a/llvm/lib/Transforms/IPO/FunctionImport.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp
@@ -125,6 +125,7 @@ static const GlobalValueSummary *
 selectCallee(const ModuleSummaryIndex &Index,
              ArrayRef<std::unique_ptr<GlobalValueSummary>> CalleeSummaryList,
              unsigned Threshold, StringRef CallerModulePath) {
+  // Find the first eligible callee (e.g. legality checks).
   auto It = llvm::find_if(
       CalleeSummaryList,
       [&](const std::unique_ptr<GlobalValueSummary> &SummaryPtr) {
@@ -160,9 +161,6 @@ selectCallee(const ModuleSummaryIndex &Index,
             Summary->modulePath() != CallerModulePath)
           return false;
 
-        if (Summary->instCount() > Threshold)
-          return false;
-
         if (Summary->notEligibleToImport())
           return false;
 
@@ -171,7 +169,19 @@ selectCallee(const ModuleSummaryIndex &Index,
   if (It == CalleeSummaryList.end())
     return nullptr;
 
-  return cast<GlobalValueSummary>(It->get());
+  // Now check if the first eligible callee is under the instruction
+  // threshold. Checking this on the first eligible callee ensures that
+  // we don't end up selecting different callees to import when we invoke
+  // this routine with different thresholds (when there are multiple copies,
+  // i.e. with weak or linkonce linkage).
+  auto *Summary = dyn_cast<FunctionSummary>(It->get());
+  if (auto *AS = dyn_cast<AliasSummary>(It->get()))
+    Summary = cast<FunctionSummary>(&AS->getAliasee());
+  assert(Summary && "Expected FunctionSummary, or alias to one");
+  if (Summary->instCount() > Threshold)
+    return nullptr;
+
+  return Summary;
 }
 
 using EdgeInfo = std::tuple<const FunctionSummary *, unsigned /* Threshold */,