2 files changed, 26 insertions, 5 deletions

diff --git a/src/tools/wasm-reduce.cpp b/src/tools/wasm-reduce.cpp
index ac00ce045..6ba5c5b83 100644
--- a/src/tools/wasm-reduce.cpp
+++ b/src/tools/wasm-reduce.cpp
@@ -566,14 +566,14 @@ struct Reducer
         }
       }
     }
-    // If that didn't work, try to replace with a child + a unary conversion
-    if (curr->type.isConcrete() &&
-        !curr->is<Unary>()) { // but not if it's already unary
+    // If that didn't work, try to replace with a child + a unary conversion,
+    // but not if it's already unary
+    if (curr->type.isSingle() && !curr->is<Unary>()) {
       for (auto* child : ChildIterator(curr)) {
         if (child->type == curr->type) {
           continue; // already tried
         }
-        if (!child->type.isConcrete()) {
+        if (!child->type.isSingle()) {
           continue; // no conversion
         }
         Expression* fixed = nullptr;
@@ -1013,6 +1013,11 @@ struct Reducer
       RefNull* n = builder->makeRefNull();
       return tryToReplaceCurrent(n);
     }
+    if (curr->type.isMulti()) {
+      Expression* n =
+        builder->makeConstExpression(Literal::makeZero(curr->type));
+      return tryToReplaceCurrent(n);
+    }
     Const* c = builder->makeConst(Literal(int32_t(0)));
     if (tryToReplaceCurrent(c)) {
       return true;
diff --git a/src/wasm-builder.h b/src/wasm-builder.h
index 1acdc40c8..f77b0577c 100644
--- a/src/wasm-builder.h
+++ b/src/wasm-builder.h
@@ -601,7 +601,7 @@ public:
     ret->finalize();
     return ret;
   }
-  TupleMake* makeTupleMake(std::vector<Expression*>&& operands) {
+  template<typename ListType> TupleMake* makeTupleMake(ListType&& operands) {
     auto* ret = allocator.alloc<TupleMake>();
     ret->operands.set(operands);
     ret->finalize();
@@ -639,6 +639,19 @@ public:
     }
   }
 
+  Expression* makeConstExpression(Literals values) {
+    assert(values.size() > 0);
+    if (values.size() == 1) {
+      return makeConstExpression(values[0]);
+    } else {
+      std::vector<Expression*> consts;
+      for (auto value : values) {
+        consts.push_back(makeConstExpression(value));
+      }
+      return makeTupleMake(consts);
+    }
+  }
+
   // Additional utility functions for building on top of nodes
   // Convenient to have these on Builder, as it has allocation built in
 
@@ -784,6 +797,9 @@ public:
   // minimal contents. as a replacement, this may reuse the
   // input node
   template<typename T> Expression* replaceWithIdenticalType(T* curr) {
+    if (curr->type.isMulti()) {
+      return makeConstExpression(Literal::makeZero(curr->type));
+    }
     Literal value;
     // TODO: reuse node conditionally when possible for literals
     switch (curr->type.getSingle()) {