Index: lib/Transforms/IPO/SampleProfile.cpp
===================================================================
--- lib/Transforms/IPO/SampleProfile.cpp
+++ lib/Transforms/IPO/SampleProfile.cpp
@@ -215,10 +215,11 @@
   bool emitAnnotations(Function &F);
   ErrorOr<uint64_t> getInstWeight(const Instruction &I);
   ErrorOr<uint64_t> getBlockWeight(const BasicBlock *BB);
-  const FunctionSamples *findCalleeFunctionSamples(const Instruction &I) const;
+  const FunctionSamples *findCalleeFunctionSamples(const Instruction &I);
   std::vector<const FunctionSamples *>
-  findIndirectCallFunctionSamples(const Instruction &I, uint64_t &Sum) const;
-  const FunctionSamples *findFunctionSamples(const Instruction &I) const;
+  findIndirectCallFunctionSamples(const Instruction &I, uint64_t &Sum);
+  DenseMap<const DILocation *, const FunctionSamples *> DILocation2SampleMap;
+  const FunctionSamples *findFunctionSamples(const Instruction &I);
   bool inlineCallInstruction(Instruction *I);
   bool inlineHotFunctions(Function &F,
                           DenseSet<GlobalValue::GUID> &InlinedGUIDs);
@@ -645,7 +646,7 @@
 ///
 /// \returns The FunctionSamples pointer to the inlined instance.
 const FunctionSamples *
-SampleProfileLoader::findCalleeFunctionSamples(const Instruction &Inst) const {
+SampleProfileLoader::findCalleeFunctionSamples(const Instruction &Inst) {
   const DILocation *DIL = Inst.getDebugLoc();
   if (!DIL) {
     return nullptr;
@@ -669,8 +670,8 @@
 /// of \p Inst. The vector is sorted by the total number of samples. Stores
 /// the total call count of the indirect call in \p Sum.
 std::vector<const FunctionSamples *>
-SampleProfileLoader::findIndirectCallFunctionSamples(
-    const Instruction &Inst, uint64_t &Sum) const {
+SampleProfileLoader::findIndirectCallFunctionSamples(const Instruction &Inst,
+                                                     uint64_t &Sum) {
   const DILocation *DIL = Inst.getDebugLoc();
   std::vector<const FunctionSamples *> R;
 
@@ -718,13 +719,17 @@
 ///
 /// \returns the FunctionSamples pointer to the inlined instance.
 const FunctionSamples *
-SampleProfileLoader::findFunctionSamples(const Instruction &Inst) const {
+SampleProfileLoader::findFunctionSamples(const Instruction &Inst) {
   SmallVector<std::pair<LineLocation, StringRef>, 10> S;
   const DILocation *DIL = Inst.getDebugLoc();
   if (!DIL)
     return Samples;
-
-  return Samples->findFunctionSamples(DIL);
+  auto it = DILocation2SampleMap.find(DIL);
+  if (it != DILocation2SampleMap.end())
+    return it->second;
+  const FunctionSamples *s = Samples->findFunctionSamples(DIL);
+  DILocation2SampleMap.try_emplace(DIL, s);
+  return s;
 }
 
 bool SampleProfileLoader::inlineCallInstruction(Instruction *I) {