diff --git a/src/testdir/test_excmd.vim b/src/testdir/test_excmd.vim
index b080575..c3a911f 100644
--- a/src/testdir/test_excmd.vim
+++ b/src/testdir/test_excmd.vim
@@ -647,4 +647,12 @@
   endif
 endfunc
 
+func Test_not_break_expression_register()
+  call setreg('=', '1+1')
+  if 0
+    put =1
+  endif
+  call assert_equal('1+1', getreg('=', 1))
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab