merge r47598 partially. extracted commits are as follows. [Bug #9728]

https://github.com/k-takata/Onigmo/commit/15ddec6d18e27fdc1988236764e766fd5892ecf5


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_1@47954 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 7 insertions, 3 deletions

diff --git a/regcomp.c b/regcomp.c
index 705e0faad7..15d71f4906 100644
--- a/regcomp.c
+++ b/regcomp.c
@@ -4495,6 +4495,9 @@ concat_opt_anc_info(OptAncInfo* to, OptAncInfo* left, OptAncInfo* right,
   if (right_len == 0) {
     to->right_anchor |= left->right_anchor;
   }
+  else {
+    to->right_anchor |= (left->right_anchor & ANCHOR_PREC_READ_NOT);
+  }
 }
 
 static int
@@ -5068,7 +5071,8 @@ optimize_node_left(Node* node, NodeOptInfo* opt, OptEnv* env)
     case ANCHOR_END_BUF:
     case ANCHOR_SEMI_END_BUF:
     case ANCHOR_END_LINE:
-    case ANCHOR_LOOK_BEHIND: /* just for (?<=x).* */
+    case ANCHOR_LOOK_BEHIND:	/* just for (?<=x).* */
+    case ANCHOR_PREC_READ_NOT:	/* just for (?!x).* */
       add_opt_anc_info(&opt->anc, NANCHOR(node)->type);
       break;
 
@@ -5091,7 +5095,6 @@ optimize_node_left(Node* node, NodeOptInfo* opt, OptEnv* env)
       }
       break;
 
-    case ANCHOR_PREC_READ_NOT:
     case ANCHOR_LOOK_BEHIND_NOT:
       break;
     }
@@ -5357,7 +5360,8 @@ set_optimize_info_from_tree(Node* node, regex_t* reg, ScanEnv* scan_env)
         ANCHOR_BEGIN_POSITION | ANCHOR_ANYCHAR_STAR | ANCHOR_ANYCHAR_STAR_ML |
         ANCHOR_LOOK_BEHIND);
 
-  reg->anchor |= opt.anc.right_anchor & (ANCHOR_END_BUF | ANCHOR_SEMI_END_BUF);
+  reg->anchor |= opt.anc.right_anchor & (ANCHOR_END_BUF | ANCHOR_SEMI_END_BUF |
+	ANCHOR_PREC_READ_NOT);
 
   if (reg->anchor & (ANCHOR_END_BUF | ANCHOR_SEMI_END_BUF)) {
     reg->anchor_dmin = opt.len.min;