From b1da8a876bd06aa8409d8dcb5a325267ca63b9c3 Mon Sep 17 00:00:00 2001
From: Alon Zakai <alonzakai@gmail.com>
Date: Fri, 7 Dec 2012 20:59:53 -0800
Subject: [PATCH] disable test_longjmp4 in optimized builds - it fails in
 native clang -O2 as well, possibly undefined behavior

---
 tests/runner.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tests/runner.py b/tests/runner.py
index 6832d41e0..1f40ed708 100755
--- a/tests/runner.py
+++ b/tests/runner.py
@@ -2131,6 +2131,8 @@ Exiting setjmp function, level: 0
 ''')
 
     def test_longjmp4(self):
+      if self.emcc_args and '-O' in str(self.emcc_args): return self.skip('this breaks with LLVM optimizations, even natively - is this undefined behavior? see issue 747')
+
       src = r'''
         #include <setjmp.h>
         #include <stdio.h>