1 files changed, 3 insertions, 1 deletions
diff --git a/src/tools/wasm-opt.cpp b/src/tools/wasm-opt.cpp
index 5238caf7a..61e554276 100644
--- a/src/tools/wasm-opt.cpp
+++ b/src/tools/wasm-opt.cpp
@@ -274,7 +274,9 @@ int main(int argc, const char* argv[]) {
     results.check(*curr);
   }
 
-  if (options.extra.count("output") > 0) {
+  if (options.extra.count("output") == 0) {
+    std::cerr << "(no output file specified, not emitting output)\n";
+  } else {
     if (options.debug) std::cerr << "writing..." << std::endl;
     ModuleWriter writer;
     writer.setDebug(options.debug);