diff --git a/llvm/lib/Transforms/IPO/Inliner.cpp b/llvm/lib/Transforms/IPO/Inliner.cpp
--- a/llvm/lib/Transforms/IPO/Inliner.cpp
+++ b/llvm/lib/Transforms/IPO/Inliner.cpp
@@ -670,6 +670,42 @@
   return *IAA->getAdvisor();
 }
 
+class InlineOrder {
+public:
+  using T = std::pair<CallBase *, int>;
+  using iterator = T *;
+  using const_iterator = const T *;
+  using reference = T &;
+
+  virtual ~InlineOrder() {}
+
+  virtual size_t size() = 0;
+  virtual reference operator[](size_t idx) = 0;
+  virtual void push_back(const T &Elt) = 0;
+  virtual T pop() = 0;
+  virtual iterator erase(const_iterator B, const_iterator E) = 0;
+  virtual iterator begin() = 0;
+  virtual iterator end() = 0;
+
+  bool empty() { return !size(); }
+};
+
+class DefaultInlineOrder : public InlineOrder {
+public:
+  size_t size() override { return Calls.size(); }
+  reference operator[](size_t idx) override { return Calls[idx]; }
+  void push_back(const T &Elt) override { Calls.push_back(Elt); }
+  T pop() override { return Calls.pop_back_val(); }
+  iterator erase(const_iterator CB, const_iterator CE) override {
+    return Calls.erase(CB, CE);
+  }
+  iterator begin() override { return Calls.begin(); }
+  iterator end() override { return Calls.end(); }
+
+private:
+  SmallVector<T, 16> Calls;
+};
+
 PreservedAnalyses InlinerPass::run(LazyCallGraph::SCC &InitialC,
                                    CGSCCAnalysisManager &AM, LazyCallGraph &CG,
                                    CGSCCUpdateResult &UR) {
@@ -714,7 +750,7 @@
   // this model, but it is uniformly spread across all the functions in the SCC
   // and eventually they all become too large to inline, rather than
   // incrementally maknig a single function grow in a super linear fashion.
-  SmallVector<std::pair<CallBase *, int>, 16> Calls;
+  DefaultInlineOrder Calls;
 
   // Populate the initial list of calls in this SCC.
   for (auto &N : InitialC) {