4 files changed, 57 insertions, 1 deletions
diff --git a/src/asm2wasm.h b/src/asm2wasm.h
index 22db2636a..16ed0cf68 100644
--- a/src/asm2wasm.h
+++ b/src/asm2wasm.h
@@ -1518,6 +1518,7 @@ void Asm2WasmBuilder::optimize() {
   passRunner.add("remove-unused-names");
   passRunner.add("merge-blocks");
   passRunner.add("simplify-locals");
+  passRunner.add("reorder-locals");
   if (maxGlobal < 1024) {
     passRunner.add("post-emscripten");
   }
diff --git a/src/binaryen-shell.cpp b/src/binaryen-shell.cpp
index 6b27333cc..68d00d019 100644
--- a/src/binaryen-shell.cpp
+++ b/src/binaryen-shell.cpp
@@ -340,7 +340,7 @@ int main(int argc, const char* argv[]) {
 
   static const char* default_passes[] = {"remove-unused-brs",
                                          "remove-unused-names", "merge-blocks",
-                                         "simplify-locals"};
+                                         "simplify-locals", "reorder-locals"};
 
   Options options("binaryen-shell", "Execute .wast files");
   options
diff --git a/src/passes/ReorderLocals.cpp b/src/passes/ReorderLocals.cpp
new file mode 100644
index 000000000..1b5e998c4
--- /dev/null
+++ b/src/passes/ReorderLocals.cpp
@@ -0,0 +1,54 @@
+/*
+ * Copyright 2016 WebAssembly Community Group participants
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+//
+// Sorts locals by access frequency.
+//
+
+
+#include <memory>
+
+#include <wasm.h>
+#include <pass.h>
+
+namespace wasm {
+
+struct ReorderLocals : public WalkerPass<WasmWalker<ReorderLocals, void>> {
+
+  std::map<Name, uint32_t> counts;
+
+  void visitFunction(Function *curr) {
+    sort(curr->locals.begin(), curr->locals.end(), [this](NameType a, NameType b) -> bool {
+      if (this->counts[a.name] == this->counts[b.name]) {
+        return strcmp(a.name.str, b.name.str) > 0;
+      }
+      return this->counts[a.name] > this->counts[b.name];
+    });
+    counts.clear();
+  }
+
+  void visitGetLocal(GetLocal *curr) {
+    counts[curr->name]++;
+  }
+
+  void visitSetLocal(SetLocal *curr) {
+    counts[curr->name]++;
+  }
+};
+
+static RegisterPass<ReorderLocals> registerPass("reorder-locals", "sorts locals by access frequency");
+
+} // namespace wasm
diff --git a/src/wasm.h b/src/wasm.h
index 387b39c02..6aff3f55e 100644
--- a/src/wasm.h
+++ b/src/wasm.h
@@ -776,6 +776,7 @@ inline const char *getExpressionName(Expression *curr) {
     case Expression::Id::UnaryId: return "unary";
     case Expression::Id::BinaryId: return "binary";
     case Expression::Id::SelectId: return "select";
+    case Expression::Id::ReturnId: return "return";
     case Expression::Id::HostId: return "host";
     case Expression::Id::NopId: return "nop";
     case Expression::Id::UnreachableId: return "unreachable";