relooper warning in emcc

2 files changed, 2 insertions, 0 deletions

diff --git a/emcc b/emcc
index c76dc82d..cd881eb4 100755
--- a/emcc
+++ b/emcc
@@ -306,6 +306,7 @@ elif use_compiler:
     shared.Settings.ASSERTIONS = 0
   if opt_level >= 2:
     shared.Settings.RELOOP = 1
+    print >> sys.stderr, 'Warning: The relooper optimization can be very slow.'
   if opt_level >= 3:
     shared.Settings.CORRECT_SIGNS = 0
     shared.Settings.CORRECT_OVERFLOWS = 0
diff --git a/tests/runner.py b/tests/runner.py
index 0ac04314..72e90e26 100644
--- a/tests/runner.py
+++ b/tests/runner.py
@@ -4948,6 +4948,7 @@ JavaScript in the final linking stage of building.
                          stdout=PIPE, stderr=PIPE).communicate(input)
           assert len(output[0]) == 0, output[0]
           assert os.path.exists('something.js'), '\n'.join(output)
+          assert ('Warning: The relooper optimization can be very slow.' in output[1]) == (opt_level >= 2), 'relooper warning should appear in opt >= 2'
           self.assertContained('hello, world!', run_js('something.js'))
 
           # Verify optimization level in the generated code