diff --git a/ChangeLog b/ChangeLog
index 0d1a67d3b9..c49d36da59 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,9 @@
-Fri Nov  9 16:08:39 2012  Sokolov Yura funny-falcon  <funny.falcon@gmail.com>
+Fri Nov  9 16:08:43 2012  Sokolov Yura funny-falcon  <funny.falcon@gmail.com>
+
+	* array.c (rb_ary_splice): use shared array in rb_ary_slice.
+	  [Feature #6638]
+	  - use ary_ensure_room_for_push when rb_ary_slice used to add at the
+	    end of array, cause rb_ary_concat use rb_ary_slice.
 
 	* array.c (ary_ensure_room_for_push): make array really suitable for
 	  queue.  [Feature #6638]
diff --git a/array.c b/array.c
index eb5d01217f..88691805ce 100644
--- a/array.c
+++ b/array.c
@@ -1388,15 +1388,12 @@ rb_ary_splice(VALUE ary, long beg, long len, VALUE rpl)
 	rpl = rb_ary_to_ary(rpl);
 	rlen = RARRAY_LEN(rpl);
     }
-    rb_ary_modify(ary);
     if (beg >= RARRAY_LEN(ary)) {
 	if (beg > ARY_MAX_SIZE - rlen) {
 	    rb_raise(rb_eIndexError, "index %ld too big", beg);
 	}
+	ary_ensure_room_for_push(ary, rlen);
 	len = beg + rlen;
-	if (len >= ARY_CAPA(ary)) {
-	    ary_double_capa(ary, len);
-	}
 	rb_mem_clear(RARRAY_PTR(ary) + RARRAY_LEN(ary), beg - RARRAY_LEN(ary));
 	if (rlen > 0) {
 	    MEMCPY(RARRAY_PTR(ary) + beg, RARRAY_PTR(rpl), VALUE, rlen);
@@ -1406,6 +1403,7 @@ rb_ary_splice(VALUE ary, long beg, long len, VALUE rpl)
     else {
 	long alen;
 
+	rb_ary_modify(ary);
 	alen = RARRAY_LEN(ary) + rlen - len;
 	if (alen >= ARY_CAPA(ary)) {
 	    ary_double_capa(ary, alen);