3 files changed, 32 insertions, 8 deletions
diff --git a/src/asm2wasm.h b/src/asm2wasm.h
index 7d4ce5fbe..fc21b945b 100644
--- a/src/asm2wasm.h
+++ b/src/asm2wasm.h
@@ -862,6 +862,7 @@ void Asm2WasmBuilder::processAsm(Ref ast) {
       if (body[i][0] == DEFUN) numFunctions++;
     }
     optimizingBuilder = make_unique<OptimizingIncrementalModuleBuilder>(&wasm, numFunctions, passOptions, [&](PassRunner& passRunner) {
+      // addPrePasses
       if (debug) {
         passRunner.setDebug(true);
         passRunner.setValidateGlobally(false);
@@ -874,6 +875,18 @@ void Asm2WasmBuilder::processAsm(Ref ast) {
       }
       // optimize relooper label variable usage at the wasm level, where it is easy
       passRunner.add("relooper-jump-threading");
+    }, [&]() {
+      // beforeGlobalOptimizations
+      // if we added any helper functions (like non-trapping i32-div, etc.), then those
+      // have not been optimized (the optimizing builder has just been fed the asm.js
+      // functions). Optimize those now. Typically there are very few, just do it
+      // sequentially.
+      PassRunner passRunner(&wasm, passOptions);
+      passRunner.addDefaultFunctionOptimizationPasses();
+      for (auto& pair : trappingFunctions.getFunctions()) {
+        auto* func = pair.second;
+        passRunner.runFunction(func);
+      }
     }, debug, false /* do not validate globally yet */);
   }
 
diff --git a/src/ast/trapping.h b/src/ast/trapping.h
index 184e6059b..7b170ccb4 100644
--- a/src/ast/trapping.h
+++ b/src/ast/trapping.h
@@ -85,6 +85,10 @@ public:
     return wasm;
   }
 
+  std::map<Name, Function*>& getFunctions() {
+    return functions;
+  }
+
 private:
   std::map<Name, Function*> functions;
   std::map<Name, Import*> imports;
diff --git a/src/wasm-module-building.h b/src/wasm-module-building.h
index c52cea9f9..61e98ba71 100644
--- a/src/wasm-module-building.h
+++ b/src/wasm-module-building.h
@@ -75,6 +75,7 @@ class OptimizingIncrementalModuleBuilder {
   uint32_t numFunctions;
   PassOptions passOptions;
   std::function<void (PassRunner&)> addPrePasses;
+  std::function<void ()> beforeGlobalOptimizations;
   Function* endMarker;
   std::atomic<Function*>* list;
   uint32_t nextFunction; // only used on main thread
@@ -90,8 +91,13 @@ class OptimizingIncrementalModuleBuilder {
 public:
   // numFunctions must be equal to the number of functions allocated, or higher. Knowing
   // this bounds helps avoid locking.
-  OptimizingIncrementalModuleBuilder(Module* wasm, Index numFunctions, PassOptions passOptions, std::function<void (PassRunner&)> addPrePasses, bool debug, bool validateGlobally)
-      : wasm(wasm), numFunctions(numFunctions), passOptions(passOptions), addPrePasses(addPrePasses), endMarker(nullptr), list(nullptr), nextFunction(0),
+  OptimizingIncrementalModuleBuilder(Module* wasm, Index numFunctions, PassOptions passOptions,
+      std::function<void (PassRunner&)> addPrePasses,
+      std::function<void ()> beforeGlobalOptimizations,
+      bool debug, bool validateGlobally)
+      : wasm(wasm), numFunctions(numFunctions), passOptions(passOptions),
+        addPrePasses(addPrePasses), beforeGlobalOptimizations(beforeGlobalOptimizations),
+        endMarker(nullptr), list(nullptr), nextFunction(0),
         numWorkers(0), liveWorkers(0), activeWorkers(0), availableFuncs(0), finishedFuncs(0),
         finishing(false), debug(debug), validateGlobally(validateGlobally) {
 
@@ -165,14 +171,13 @@ public:
       }
       addPrePasses(passRunner);
       passRunner.addDefaultFunctionOptimizationPasses();
-      passRunner.addDefaultGlobalOptimizationPostPasses();
       passRunner.run();
-      return;
+    } else {
+      DEBUG_THREAD("finish()ing");
+      assert(nextFunction == numFunctions);
+      wakeAllWorkers();
+      waitUntilAllFinished();
     }
-    DEBUG_THREAD("finish()ing");
-    assert(nextFunction == numFunctions);
-    wakeAllWorkers();
-    waitUntilAllFinished();
     optimizeGlobally();
     // TODO: clear side thread allocators from module allocator, as these threads were transient
   }
@@ -225,9 +230,11 @@ private:
   }
 
   void optimizeGlobally() {
+    beforeGlobalOptimizations();
     PassRunner passRunner(wasm, passOptions);
     passRunner.addDefaultGlobalOptimizationPostPasses();
     passRunner.run();
+
   }
 
   // worker code