[d7ea9f9853] Contributed patch from tgl with Postgres.

1 files changed, 9 insertions, 7 deletions

diff --git a/generic/regcomp.c b/generic/regcomp.c
index d23076b..b1c02d8 100644
--- a/generic/regcomp.c
+++ b/generic/regcomp.c
@@ -593,13 +593,15 @@ makesearch(
 		break;
 	    }
 	}
+ 
+	/*
+	 * We want to mark states as being in the list already by having non
+	 * NULL tmp fields, but we can't just store the old slist value in tmp
+	 * because that doesn't work for the first such state.  Instead, the
+	 * first list entry gets its own address in tmp.
+	 */
 	if (b != NULL && s->tmp == NULL) {
-	    /*
-	     * Must be split if not already in the list (fixes bugs 505048,
-	     * 230589, 840258, 504785).
-	     */
-
-	    s->tmp = slist;
+	    s->tmp = (slist != NULL) ? slist : s;
 	    slist = s;
 	}
     }
@@ -620,7 +622,7 @@ makesearch(
 		freearc(nfa, a);
 	    }
 	}
-	s2 = s->tmp;
+	s2 = (s->tmp != s) ? s->tmp : NULL;
 	s->tmp = NULL;		/* clean up while we're at it */
     }
 }