Index: lib/Transforms/IPO/SampleProfile.cpp
===================================================================
--- lib/Transforms/IPO/SampleProfile.cpp
+++ lib/Transforms/IPO/SampleProfile.cpp
@@ -218,6 +218,7 @@
   const FunctionSamples *findCalleeFunctionSamples(const Instruction &I) const;
   std::vector<const FunctionSamples *>
   findIndirectCallFunctionSamples(const Instruction &I, uint64_t &Sum) const;
+  mutable DenseMap<const DILocation *, const FunctionSamples *> DILocation2SampleMap;
   const FunctionSamples *findFunctionSamples(const Instruction &I) const;
   bool inlineCallInstruction(Instruction *I);
   bool inlineHotFunctions(Function &F,
@@ -719,12 +720,14 @@
 /// \returns the FunctionSamples pointer to the inlined instance.
 const FunctionSamples *
 SampleProfileLoader::findFunctionSamples(const Instruction &Inst) const {
-  SmallVector<std::pair<LineLocation, StringRef>, 10> S;
   const DILocation *DIL = Inst.getDebugLoc();
   if (!DIL)
     return Samples;
 
-  return Samples->findFunctionSamples(DIL);
+  auto it = DILocation2SampleMap.try_emplace(DIL,nullptr);
+  if (it.second)
+    it.first->second = Samples->findFunctionSamples(DIL);
+  return it.first->second;
 }
 
 bool SampleProfileLoader::inlineCallInstruction(Instruction *I) {