2 files changed, 26 insertions, 3 deletions
diff --git a/src/ir/gc-type-utils.h b/src/ir/gc-type-utils.h
index 1fecca22e..53cc6feb2 100644
--- a/src/ir/gc-type-utils.h
+++ b/src/ir/gc-type-utils.h
@@ -105,6 +105,28 @@ inline EvaluationResult evaluateCastCheck(Type refType, Type castType) {
   return Unknown;
 }
 
+// Given a reference and a field index, return the field for it, if one exists.
+// One may not exist if the reference is unreachable, or a bottom type.
+//
+// The index is optional as it does not matter for an array.
+//
+// TODO: use in more places
+inline std::optional<Field> getField(HeapType type, Index index = 0) {
+  if (type.isStruct()) {
+    return type.getStruct().fields[index];
+  } else if (type.isArray()) {
+    return type.getArray().element;
+  }
+  return {};
+}
+
+inline std::optional<Field> getField(Type type, Index index = 0) {
+  if (type.isRef()) {
+    return getField(type.getHeapType(), index);
+  }
+  return {};
+}
+
 } // namespace wasm::GCTypeUtils
 
 #endif // wasm_ir_gc_type_utils_h
diff --git a/src/passes/OptimizeInstructions.cpp b/src/passes/OptimizeInstructions.cpp
index e71519012..e6b19a6de 100644
--- a/src/passes/OptimizeInstructions.cpp
+++ b/src/passes/OptimizeInstructions.cpp
@@ -1941,9 +1941,10 @@ struct OptimizeInstructions
       return;
     }
 
-    if (curr->ref->type != Type::unreachable && curr->value->type.isInteger()) {
-      auto element = curr->ref->type.getHeapType().getArray().element;
-      optimizeStoredValue(curr->value, element.getByteSize());
+    if (curr->value->type.isInteger()) {
+      if (auto field = GCTypeUtils::getField(curr->ref->type)) {
+        optimizeStoredValue(curr->value, field->getByteSize());
+      }
     }
   }