Index: pcre_compile.c
===================================================================
--- a/pcre_compile.c	(revision 1569)
+++ b/pcre_compile.c	(revision 1575)
@@ -9449,7 +9449,7 @@
 exceptional ones forgo this. We scan the pattern to check that they are fixed
 length, and set their lengths. */
 
-if (cd->check_lookbehind)
+if (errorcode == 0 && cd->check_lookbehind)
   {
   pcre_uchar *cc = (pcre_uchar *)codestart;