fix perl-126222 - (?!) OPFAIL optimization does work in (?(?!)yes|no)

OPFAIL should trigger the no branch when used in this context

Thanks to Victor Adam for the report.

1 files changed, 9 insertions, 1 deletions

diff --git a/regexec.c b/regexec.c
index 15b28e56d1..96def0f2ca 100644
--- a/regexec.c
+++ b/regexec.c
@@ -7722,7 +7722,15 @@ NULL
 	    /* FALLTHROUGH */	    
 
 	case OPFAIL:   /* (*FAIL)  */
-	    sayNO;
+            if (logical) {
+                /* deal with (?(?!)X|Y) properly,
+                 * make sure we trigger the no branch
+                 * of the trailing IFTHEN structure*/
+                sw= 0;
+                break;
+            } else {
+                sayNO;
+            }
             /* NOTREACHED */
 	    NOT_REACHED; /* NOTREACHED */