diff --git a/llvm/lib/Analysis/InlineSizeEstimatorAnalysis.cpp b/llvm/lib/Analysis/InlineSizeEstimatorAnalysis.cpp
--- a/llvm/lib/Analysis/InlineSizeEstimatorAnalysis.cpp
+++ b/llvm/lib/Analysis/InlineSizeEstimatorAnalysis.cpp
@@ -67,7 +67,7 @@
   static const size_t NumNamedFeatures =
       static_cast<size_t>(NamedFeatureIndex::NumNamedFeatures);
   struct FunctionFeatures {
-    static std::vector<std::pair<size_t, size_t>>
+    static const std::array<std::pair<size_t, size_t>, 137>
         ImportantInstructionSuccessions;
     static const size_t FeatureCount;
 
@@ -86,51 +86,43 @@
                                               FunctionAnalysisManager &FAM);
 
 private:
-  /// Sort once the feature tuples.
-  struct SortFeatureTuples {
-    bool IsSorted = false;
-    SortFeatureTuples() {
-      std::sort(FunctionFeatures::ImportantInstructionSuccessions.begin(),
-                FunctionFeatures::ImportantInstructionSuccessions.end());
-      IsSorted = true;
-    }
-  };
-
-  static llvm::ManagedStatic<SortFeatureTuples> TupleSorter;
-
-  static bool ensureSortedTuples() { return TupleSorter->IsSorted; }
+  static bool ensureSortedTuples() {
+    return std::is_sorted(
+        FunctionFeatures::ImportantInstructionSuccessions.begin(),
+        FunctionFeatures::ImportantInstructionSuccessions.end());
+  }
 };
-llvm::ManagedStatic<IRToNativeSizeLearning::SortFeatureTuples>
-    IRToNativeSizeLearning::TupleSorter;
 
 // This is a point in time - we determined including these pairs of
 // consecutive instructions (in the IR layout available at inline time) as
 // features improves the model performance. We want to move away from manual
 // feature selection.
-// The vector is given in opcode pairs rather than labels because 1) labels
-// weren't readily available, and 2) the successions were hand - extracted
-std::vector<std::pair<size_t, size_t>>
-    IRToNativeSizeLearning::FunctionFeatures::ImportantInstructionSuccessions =
-        {{1, 34},  {15, 27}, {53, 53}, {53, 34}, {1, 11},  {32, 2},  {2, 48},
-         {28, 48}, {1, 45},  {49, 32}, {57, 56}, {55, 53}, {1, 28},  {57, 34},
-         {1, 1},   {32, 28}, {32, 15}, {49, 28}, {53, 1},  {2, 53},  {48, 34},
-         {28, 53}, {2, 32},  {1, 40},  {32, 48}, {29, 56}, {56, 32}, {55, 56},
-         {48, 56}, {1, 31},  {33, 34}, {2, 28},  {1, 12},  {55, 1},  {31, 31},
-         {65, 1},  {33, 56}, {32, 32}, {13, 13}, {1, 26},  {13, 26}, {2, 1},
-         {1, 33},  {47, 49}, {64, 1},  {2, 38},  {34, 53}, {48, 2},  {55, 34},
-         {34, 32}, {1, 5},   {56, 13}, {2, 2},   {2, 49},  {33, 2},  {49, 39},
-         {56, 49}, {33, 49}, {32, 39}, {39, 57}, {29, 33}, {31, 34}, {32, 29},
-         {47, 15}, {13, 34}, {2, 33},  {32, 49}, {49, 34}, {56, 33}, {1, 30},
-         {33, 33}, {31, 33}, {2, 29},  {56, 7},  {32, 13}, {2, 55},  {56, 56},
-         {2, 34},  {1, 42},  {34, 49}, {1, 20},  {32, 33}, {1, 25},  {53, 28},
-         {1, 14},  {31, 49}, {28, 2},  {2, 13},  {2, 56},  {1, 32},  {56, 53},
-         {65, 65}, {33, 53}, {64, 64}, {13, 2},  {34, 33}, {1, 4},   {49, 2},
-         {1, 9},   {56, 1},  {33, 1},  {53, 57}, {32, 53}, {13, 56}, {32, 56},
-         {55, 55}, {1, 18},  {49, 56}, {34, 34}, {1, 7},   {56, 64}, {32, 1},
-         {13, 33}, {55, 28}, {49, 33}, {57, 57}, {56, 34}, {34, 56}, {33, 32},
-         {32, 40}, {1, 29},  {53, 2},  {34, 1},  {32, 34}, {49, 49}, {1, 24},
-         {40, 34}, {1, 13},  {38, 34}, {29, 2},  {34, 2},  {1, 39},  {1, 22},
-         {1, 27},  {49, 1},  {1, 8},   {56, 2}};
+// The array is given in opcode pairs rather than labels because 1) labels
+// weren't readily available, and 2) the successions were hand - extracted.
+//
+// This array must be sorted.
+const std::array<std::pair<size_t, size_t>, 137>
+    IRToNativeSizeLearning::FunctionFeatures::ImportantInstructionSuccessions{
+        {{1, 1},   {1, 4},   {1, 5},   {1, 7},   {1, 8},   {1, 9},   {1, 11},
+         {1, 12},  {1, 13},  {1, 14},  {1, 18},  {1, 20},  {1, 22},  {1, 24},
+         {1, 25},  {1, 26},  {1, 27},  {1, 28},  {1, 29},  {1, 30},  {1, 31},
+         {1, 32},  {1, 33},  {1, 34},  {1, 39},  {1, 40},  {1, 42},  {1, 45},
+         {2, 1},   {2, 2},   {2, 13},  {2, 28},  {2, 29},  {2, 32},  {2, 33},
+         {2, 34},  {2, 38},  {2, 48},  {2, 49},  {2, 53},  {2, 55},  {2, 56},
+         {13, 2},  {13, 13}, {13, 26}, {13, 33}, {13, 34}, {13, 56}, {15, 27},
+         {28, 2},  {28, 48}, {28, 53}, {29, 2},  {29, 33}, {29, 56}, {31, 31},
+         {31, 33}, {31, 34}, {31, 49}, {32, 1},  {32, 2},  {32, 13}, {32, 15},
+         {32, 28}, {32, 29}, {32, 32}, {32, 33}, {32, 34}, {32, 39}, {32, 40},
+         {32, 48}, {32, 49}, {32, 53}, {32, 56}, {33, 1},  {33, 2},  {33, 32},
+         {33, 33}, {33, 34}, {33, 49}, {33, 53}, {33, 56}, {34, 1},  {34, 2},
+         {34, 32}, {34, 33}, {34, 34}, {34, 49}, {34, 53}, {34, 56}, {38, 34},
+         {39, 57}, {40, 34}, {47, 15}, {47, 49}, {48, 2},  {48, 34}, {48, 56},
+         {49, 1},  {49, 2},  {49, 28}, {49, 32}, {49, 33}, {49, 34}, {49, 39},
+         {49, 49}, {49, 56}, {53, 1},  {53, 2},  {53, 28}, {53, 34}, {53, 53},
+         {53, 57}, {55, 1},  {55, 28}, {55, 34}, {55, 53}, {55, 55}, {55, 56},
+         {56, 1},  {56, 2},  {56, 7},  {56, 13}, {56, 32}, {56, 33}, {56, 34},
+         {56, 49}, {56, 53}, {56, 56}, {56, 64}, {57, 34}, {57, 56}, {57, 57},
+         {64, 1},  {64, 64}, {65, 1},  {65, 65}}};
 
 // We have: 9 calculated features (the features here); 1 feature for each
 // instruction opcode; and 1 feature for each manually-identified sequence.
@@ -171,7 +163,7 @@
 IRToNativeSizeLearning::FunctionFeatures
 IRToNativeSizeLearning::getFunctionFeatures(Function &F,
                                             FunctionAnalysisManager &FAM) {
-  ensureSortedTuples();
+  assert(ensureSortedTuples() && "expected function features are sorted");
 
   auto &DomTree = FAM.getResult<DominatorTreeAnalysis>(F);
   FunctionFeatures FF;