diff --git a/src/buffer.c b/src/buffer.c
index 4055af9..0ac76b0 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -5865,6 +5865,73 @@
 #endif
 
 #if defined(FEAT_SIGNS) || defined(PROTO)
+static hashtab_T	sg_table;	// sign group (signgroup_T) hashtable
+
+/*
+ * A new sign in group 'groupname' is added. If the group is not present,
+ * create it. Otherwise reference the group.
+ */
+    static signgroup_T *
+sign_group_ref(char_u *groupname)
+{
+    static int		initialized = FALSE;
+    hash_T		hash;
+    hashitem_T		*hi;
+    signgroup_T		*group;
+
+    if (!initialized)
+    {
+	initialized = TRUE;
+	hash_init(&sg_table);
+    }
+
+    hash = hash_hash(groupname);
+    hi = hash_lookup(&sg_table, groupname, hash);
+    if (HASHITEM_EMPTY(hi))
+    {
+	// new group
+	group = (signgroup_T *)alloc(
+		(unsigned)(sizeof(signgroup_T) + STRLEN(groupname)));
+	if (group == NULL)
+	    return NULL;
+	STRCPY(group->sg_name, groupname);
+	group->refcount = 1;
+	hash_add_item(&sg_table, hi, group->sg_name, hash);
+    }
+    else
+    {
+	// existing group
+	group = HI2SG(hi);
+	group->refcount++;
+    }
+
+    return group;
+}
+
+/*
+ * A sign in group 'groupname' is removed. If all the signs in this group are
+ * removed, then remove the group.
+ */
+    static void
+sign_group_unref(char_u *groupname)
+{
+    hashitem_T		*hi;
+    signgroup_T		*group;
+
+    hi = hash_find(&sg_table, groupname);
+    if (!HASHITEM_EMPTY(hi))
+    {
+	group = HI2SG(hi);
+	group->refcount--;
+	if (group->refcount == 0)
+	{
+	    // All the signs in this group are removed
+	    hash_remove(&sg_table, hi);
+	    vim_free(group);
+	}
+    }
+}
+
 /*
  * Insert a new sign into the signlist for buffer 'buf' between the 'prev' and
  * 'next' signs.
@@ -5890,7 +5957,14 @@
 	newsign->lnum = lnum;
 	newsign->typenr = typenr;
 	if (group != NULL)
-	    newsign->group = vim_strsave(group);
+	{
+	    newsign->group = sign_group_ref(group);
+	    if (newsign->group == NULL)
+	    {
+		vim_free(newsign);
+		return;
+	    }
+	}
 	else
 	    newsign->group = NULL;
 	newsign->priority = prio;
@@ -5959,7 +6033,7 @@
     return ((group != NULL && STRCMP(group, "*") == 0) ||
 	    (group == NULL && sign->group == NULL) ||
 	    (group != NULL && sign->group != NULL &&
-					STRCMP(group, sign->group) == 0));
+				STRCMP(group, sign->group->sg_name) == 0));
 }
 
 /*
@@ -5974,7 +6048,7 @@
 	return NULL;
     dict_add_number(d, "id", sign->id);
     dict_add_string(d, "group", (sign->group == NULL) ?
-						(char_u *)"" : sign->group);
+					(char_u *)"" : sign->group->sg_name);
     dict_add_number(d, "lnum", sign->lnum);
     dict_add_string(d, "name", sign_typenr2name(sign->typenr));
     dict_add_number(d, "priority", sign->priority);
@@ -5989,7 +6063,7 @@
 buf_addsign(
     buf_T	*buf,		// buffer to store sign in
     int		id,		// sign ID
-    char_u	*group,		// sign group
+    char_u	*groupname,	// sign group
     int		prio,		// sign priority
     linenr_T	lnum,		// line number which gets the mark
     int		typenr)		// typenr of sign we are adding
@@ -6001,7 +6075,7 @@
     FOR_ALL_SIGNS_IN_BUF(buf)
     {
 	if (lnum == sign->lnum && id == sign->id &&
-		sign_in_group(sign, group))
+		sign_in_group(sign, groupname))
 	{
 	    // Update an existing sign
 	    sign->typenr = typenr;
@@ -6009,14 +6083,14 @@
 	}
 	else if (lnum < sign->lnum)
 	{
-	    insert_sign_by_lnum_prio(buf, prev, id, group, prio, lnum, typenr);
+	    insert_sign_by_lnum_prio(buf, prev, id, groupname, prio,
+								lnum, typenr);
 	    return;
 	}
 	prev = sign;
     }
 
-    insert_sign_by_lnum_prio(buf, prev, id, group, prio, lnum, typenr);
-
+    insert_sign_by_lnum_prio(buf, prev, id, groupname, prio, lnum, typenr);
     return;
 }
 
@@ -6106,7 +6180,8 @@
 	    if (next != NULL)
 		next->prev = sign->prev;
 	    lnum = sign->lnum;
-	    vim_free(sign->group);
+	    if (sign->group != NULL)
+		sign_group_unref(sign->group->sg_name);
 	    vim_free(sign);
 	    // Check whether only one sign needs to be deleted
 	    if (group == NULL || (*group != '*' && id != 0))
@@ -6269,7 +6344,8 @@
 	    *lastp = next;
 	    if (next != NULL)
 		next->prev = sign->prev;
-	    vim_free(sign->group);
+	    if (sign->group != NULL)
+		sign_group_unref(sign->group->sg_name);
 	    vim_free(sign);
 	}
 	else
@@ -6317,10 +6393,13 @@
 	}
 	FOR_ALL_SIGNS_IN_BUF(buf)
 	{
+	    if (got_int)
+		break;
 	    if (!sign_in_group(sign, sign_group))
 		continue;
 	    if (sign->group != NULL)
-		vim_snprintf(group, BUFSIZ, "  group=%s", sign->group);
+		vim_snprintf(group, BUFSIZ, "  group=%s",
+							sign->group->sg_name);
 	    else
 		group[0] = '\0';
 	    vim_snprintf(lbuf, BUFSIZ, _("    line=%ld  id=%d%s  name=%s "
diff --git a/src/ex_cmds.c b/src/ex_cmds.c
index 06df5af..52b669a 100644
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -8180,7 +8180,7 @@
 	{
 	    EMSG2(_("E158: Invalid buffer name: %s"), arg);
 	}
-	else if (id <= 0 && !(idx == SIGNCMD_UNPLACE && id == -2))
+	else if (id <= 0 && idx == SIGNCMD_PLACE)
 	{
 	    if ((group == NULL) && (lnum >= 0 || sign_name != NULL))
 		EMSG(_(e_invarg));
diff --git a/src/structs.h b/src/structs.h
index 0f37b8f..e4311ed 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -733,6 +733,17 @@
 
 
 #if defined(FEAT_SIGNS) || defined(PROTO)
+// Sign group
+typedef struct signgroup_S
+{
+    short_u	refcount;		// number of signs in this group
+    char_u	sg_name[1];		// sign group name
+} signgroup_T;
+
+// Macros to get the sign group structure from the group name
+#define SGN_KEY_OFF	offsetof(signgroup_T, sg_name)
+#define HI2SG(hi)	((signgroup_T *)((hi)->hi_key - SGN_KEY_OFF))
+
 typedef struct signlist signlist_T;
 
 struct signlist
@@ -740,7 +751,7 @@
     int		id;		/* unique identifier for each placed sign */
     linenr_T	lnum;		/* line number which has this sign */
     int		typenr;		/* typenr of sign */
-    char_u	*group;		/* sign group */
+    signgroup_T	*group;		/* sign group */
     int		priority;	/* priority for highlighting */
     signlist_T	*next;		/* next signlist entry */
     signlist_T  *prev;		/* previous entry -- for easy reordering */
diff --git a/src/testdir/test_signs.vim b/src/testdir/test_signs.vim
index 07705c7..0f589c5 100644
--- a/src/testdir/test_signs.vim
+++ b/src/testdir/test_signs.vim
@@ -59,7 +59,7 @@
   redraw
 
   " Check that we can't change sign.
-  call assert_fails("exe 'sign place 40 name=Sign1 buffer=' . bufnr('%')", 'E885:')
+  call assert_fails("sign place 40 name=Sign1 buffer=" . bufnr('%'), 'E885:')
 
   " Check placed signs
   let a=execute('sign place')
@@ -68,7 +68,7 @@
   " Unplace the sign and try jumping to it again should fail.
   sign unplace 41
   1
-  call assert_fails("exe 'sign jump 41 buffer=' . bufnr('%')", 'E157:')
+  call assert_fails("sign jump 41 buffer=" . bufnr('%'), 'E157:')
   call assert_equal('a', getline('.'))
 
   " Unplace sign on current line.
@@ -132,17 +132,22 @@
   sign undefine Sign4
 
   " Error cases
-  call assert_fails("exe 'sign place abc line=3 name=Sign1 buffer=' . bufnr('%')", 'E474:')
-  call assert_fails("exe 'sign unplace abc name=Sign1 buffer=' . bufnr('%')", 'E474:')
-  call assert_fails("exe 'sign place 1abc line=3 name=Sign1 buffer=' . bufnr('%')", 'E474:')
-  call assert_fails("exe 'sign unplace 2abc name=Sign1 buffer=' . bufnr('%')", 'E474:')
+  call assert_fails("sign place abc line=3 name=Sign1 buffer=" .
+			  \ bufnr('%'), 'E474:')
+  call assert_fails("sign unplace abc name=Sign1 buffer=" .
+			  \ bufnr('%'), 'E474:')
+  call assert_fails("sign place 1abc line=3 name=Sign1 buffer=" .
+			  \ bufnr('%'), 'E474:')
+  call assert_fails("sign unplace 2abc name=Sign1 buffer=" .
+			  \ bufnr('%'), 'E474:')
   call assert_fails("sign unplace 2 *", 'E474:')
-  call assert_fails("exe 'sign place 1 line=3 name=Sign1 buffer=' . bufnr('%') a", 'E488:')
-  call assert_fails("exe 'sign place name=Sign1 buffer=' . bufnr('%')", 'E474:')
-  call assert_fails("exe 'sign place line=10 buffer=' . bufnr('%')", 'E474:')
-  call assert_fails("exe 'sign unplace 2 line=10 buffer=' . bufnr('%')", 'E474:')
-  call assert_fails("exe 'sign unplace 2 name=Sign1 buffer=' . bufnr('%')", 'E474:')
-  call assert_fails("exe 'sign place 2 line=3 buffer=' . bufnr('%')", 'E474:')
+  call assert_fails("sign place 1 line=3 name=Sign1 buffer=" .
+			  \ bufnr('%') . " a", 'E488:')
+  call assert_fails("sign place name=Sign1 buffer=" . bufnr('%'), 'E474:')
+  call assert_fails("sign place line=10 buffer=" . bufnr('%'), 'E474:')
+  call assert_fails("sign unplace 2 line=10 buffer=" . bufnr('%'), 'E474:')
+  call assert_fails("sign unplace 2 name=Sign1 buffer=" . bufnr('%'), 'E474:')
+  call assert_fails("sign place 2 line=3 buffer=" . bufnr('%'), 'E474:')
   call assert_fails("sign place 2", 'E474:')
   call assert_fails("sign place abc", 'E474:')
   call assert_fails("sign place 5 line=3", 'E474:')
@@ -157,7 +162,8 @@
   sign undefine Sign1
   sign undefine Sign2
   sign undefine Sign3
-  call assert_fails("exe 'sign place 41 line=3 name=Sign1 buffer=' . bufnr('%')", 'E155:')
+  call assert_fails("sign place 41 line=3 name=Sign1 buffer=" .
+			  \ bufnr('%'), 'E155:')
 endfunc
 
 " Undefining placed sign is not recommended.
@@ -236,33 +242,33 @@
   call assert_fails('sign place 1 buffer=999', 'E158:')
   call assert_fails('sign define Sign2 text=', 'E239:')
   " Non-numeric identifier for :sign place
-  call assert_fails("exe 'sign place abc line=3 name=Sign1 buffer=' . bufnr('%')", 'E474:')
+  call assert_fails("sign place abc line=3 name=Sign1 buffer=" . bufnr('%'), 'E474:')
   " Non-numeric identifier for :sign unplace
-  call assert_fails("exe 'sign unplace abc name=Sign1 buffer=' . bufnr('%')", 'E474:')
+  call assert_fails("sign unplace abc name=Sign1 buffer=" . bufnr('%'), 'E474:')
   " Number followed by an alphabet as sign identifier for :sign place
-  call assert_fails("exe 'sign place 1abc line=3 name=Sign1 buffer=' . bufnr('%')", 'E474:')
+  call assert_fails("sign place 1abc line=3 name=Sign1 buffer=" . bufnr('%'), 'E474:')
   " Number followed by an alphabet as sign identifier for :sign unplace
-  call assert_fails("exe 'sign unplace 2abc name=Sign1 buffer=' . bufnr('%')", 'E474:')
+  call assert_fails("sign unplace 2abc name=Sign1 buffer=" . bufnr('%'), 'E474:')
   " Sign identifier and '*' for :sign unplace
   call assert_fails("sign unplace 2 *", 'E474:')
   " Trailing characters after buffer number for :sign place
-  call assert_fails("exe 'sign place 1 line=3 name=Sign1 buffer=' . bufnr('%') . 'xxx'", 'E488:')
+  call assert_fails("sign place 1 line=3 name=Sign1 buffer=" . bufnr('%') . 'xxx', 'E488:')
   " Trailing characters after buffer number for :sign unplace
-  call assert_fails("exe 'sign unplace 1 buffer=' . bufnr('%') . 'xxx'", 'E488:')
-  call assert_fails("exe 'sign unplace * buffer=' . bufnr('%') . 'xxx'", 'E488:')
+  call assert_fails("sign unplace 1 buffer=" . bufnr('%') . 'xxx', 'E488:')
+  call assert_fails("sign unplace * buffer=" . bufnr('%') . 'xxx', 'E488:')
   call assert_fails("sign unplace 1 xxx", 'E474:')
   call assert_fails("sign unplace * xxx", 'E474:')
   call assert_fails("sign unplace xxx", 'E474:')
   " Placing a sign without line number
-  call assert_fails("exe 'sign place name=Sign1 buffer=' . bufnr('%')", 'E474:')
+  call assert_fails("sign place name=Sign1 buffer=" . bufnr('%'), 'E474:')
   " Placing a sign without sign name
-  call assert_fails("exe 'sign place line=10 buffer=' . bufnr('%')", 'E474:')
+  call assert_fails("sign place line=10 buffer=" . bufnr('%'), 'E474:')
   " Unplacing a sign with line number
-  call assert_fails("exe 'sign unplace 2 line=10 buffer=' . bufnr('%')", 'E474:')
+  call assert_fails("sign unplace 2 line=10 buffer=" . bufnr('%'), 'E474:')
   " Unplacing a sign with sign name
-  call assert_fails("exe 'sign unplace 2 name=Sign1 buffer=' . bufnr('%')", 'E474:')
+  call assert_fails("sign unplace 2 name=Sign1 buffer=" . bufnr('%'), 'E474:')
   " Placing a sign without sign name
-  call assert_fails("exe 'sign place 2 line=3 buffer=' . bufnr('%')", 'E474:')
+  call assert_fails("sign place 2 line=3 buffer=" . bufnr('%'), 'E474:')
   " Placing a sign with only sign identifier
   call assert_fails("sign place 2", 'E474:')
   " Placing a sign with only a name
@@ -574,24 +580,24 @@
   call sign_unplace('*')
 
   " Test for :sign command and groups
-  exe 'sign place 5 line=10 name=sign1 file=' . fname
-  exe 'sign place 5 group=g1 line=10 name=sign1 file=' . fname
-  exe 'sign place 5 group=g2 line=10 name=sign1 file=' . fname
+  sign place 5 line=10 name=sign1 file=Xsign
+  sign place 5 group=g1 line=10 name=sign1 file=Xsign
+  sign place 5 group=g2 line=10 name=sign1 file=Xsign
 
   " Test for :sign place group={group} file={fname}
-  let a = execute('sign place file=' . fname)
+  let a = execute('sign place file=Xsign')
   call assert_equal("\n--- Signs ---\nSigns for Xsign:\n    line=10  id=5  name=sign1 priority=10\n", a)
 
-  let a = execute('sign place group=g2 file=' . fname)
+  let a = execute('sign place group=g2 file=Xsign')
   call assert_equal("\n--- Signs ---\nSigns for Xsign:\n    line=10  id=5  group=g2  name=sign1 priority=10\n", a)
 
-  let a = execute('sign place group=* file=' . fname)
+  let a = execute('sign place group=* file=Xsign')
   call assert_equal("\n--- Signs ---\nSigns for Xsign:\n" .
 	      \ "    line=10  id=5  group=g2  name=sign1 priority=10\n" .
 	      \ "    line=10  id=5  group=g1  name=sign1 priority=10\n" .
 	      \ "    line=10  id=5  name=sign1 priority=10\n", a)
 
-  let a = execute('sign place group=xyz file=' . fname)
+  let a = execute('sign place group=xyz file=Xsign')
   call assert_equal("\n--- Signs ---\nSigns for Xsign:\n", a)
 
   call sign_unplace('*')
@@ -624,22 +630,22 @@
 	      \ "    line=12  id=5  group=g2  name=sign1 priority=10\n", a)
 
   " Test for :sign unplace
-  exe 'sign unplace 5 group=g2 file=' . fname
+  sign unplace 5 group=g2 file=Xsign
   call assert_equal([], sign_getplaced(bnum, {'group' : 'g2'})[0].signs)
 
   exe 'sign unplace 5 group=g1 buffer=' . bnum
   call assert_equal([], sign_getplaced(bnum, {'group' : 'g1'})[0].signs)
 
-  exe 'sign unplace 5 group=xy file=' . fname
+  sign unplace 5 group=xy file=Xsign
   call assert_equal(1, len(sign_getplaced(bnum, {'group' : '*'})[0].signs))
 
   " Test for removing all the signs. Place the signs again for this test
-  exe 'sign place 5 group=g1 line=11 name=sign1 file=' . fname
-  exe 'sign place 5 group=g2 line=12 name=sign1 file=' . fname
-  exe 'sign place 6 line=20 name=sign1 file=' . fname
-  exe 'sign place 6 group=g1 line=21 name=sign1 file=' . fname
-  exe 'sign place 6 group=g2 line=22 name=sign1 file=' . fname
-  exe 'sign unplace 5 group=* file=' . fname
+  sign place 5 group=g1 line=11 name=sign1 file=Xsign
+  sign place 5 group=g2 line=12 name=sign1 file=Xsign
+  sign place 6 line=20 name=sign1 file=Xsign
+  sign place 6 group=g1 line=21 name=sign1 file=Xsign
+  sign place 6 group=g2 line=22 name=sign1 file=Xsign
+  sign unplace 5 group=* file=Xsign
   let a = execute('sign place group=*')
   call assert_equal("\n--- Signs ---\nSigns for Xsign:\n" .
 	      \ "    line=20  id=6  name=sign1 priority=10\n" .
@@ -647,17 +653,17 @@
 	      \ "    line=22  id=6  group=g2  name=sign1 priority=10\n", a)
 
   " Remove all the signs from the global group
-  exe 'sign unplace * file=' . fname
+  sign unplace * file=Xsign
   let a = execute('sign place group=*')
   call assert_equal("\n--- Signs ---\nSigns for Xsign:\n" .
 	      \ "    line=21  id=6  group=g1  name=sign1 priority=10\n" .
 	      \ "    line=22  id=6  group=g2  name=sign1 priority=10\n", a)
 
   " Remove all the signs from a particular group
-  exe 'sign place 5 line=10 name=sign1 file=' . fname
-  exe 'sign place 5 group=g1 line=11 name=sign1 file=' . fname
-  exe 'sign place 5 group=g2 line=12 name=sign1 file=' . fname
-  exe 'sign unplace * group=g1 file=' . fname
+  sign place 5 line=10 name=sign1 file=Xsign
+  sign place 5 group=g1 line=11 name=sign1 file=Xsign
+  sign place 5 group=g2 line=12 name=sign1 file=Xsign
+  sign unplace * group=g1 file=Xsign
   let a = execute('sign place group=*')
   call assert_equal("\n--- Signs ---\nSigns for Xsign:\n" .
 	      \ "    line=10  id=5  name=sign1 priority=10\n" .
@@ -665,26 +671,26 @@
 	      \ "    line=22  id=6  group=g2  name=sign1 priority=10\n", a)
 
   " Remove all the signs from all the groups in a file
-  exe 'sign place 5 group=g1 line=11 name=sign1 file=' . fname
-  exe 'sign place 6 line=20 name=sign1 file=' . fname
-  exe 'sign place 6 group=g1 line=21 name=sign1 file=' . fname
-  exe 'sign unplace * group=* file=' . fname
+  sign place 5 group=g1 line=11 name=sign1 file=Xsign
+  sign place 6 line=20 name=sign1 file=Xsign
+  sign place 6 group=g1 line=21 name=sign1 file=Xsign
+  sign unplace * group=* file=Xsign
   let a = execute('sign place group=*')
   call assert_equal("\n--- Signs ---\n", a)
 
   " Remove a particular sign id in a group from all the files
-  exe 'sign place 5 group=g1 line=11 name=sign1 file=' . fname
+  sign place 5 group=g1 line=11 name=sign1 file=Xsign
   sign unplace 5 group=g1
   let a = execute('sign place group=*')
   call assert_equal("\n--- Signs ---\n", a)
 
   " Remove a particular sign id in all the groups from all the files
-  exe 'sign place 5 line=10 name=sign1 file=' . fname
-  exe 'sign place 5 group=g1 line=11 name=sign1 file=' . fname
-  exe 'sign place 5 group=g2 line=12 name=sign1 file=' . fname
-  exe 'sign place 6 line=20 name=sign1 file=' . fname
-  exe 'sign place 6 group=g1 line=21 name=sign1 file=' . fname
-  exe 'sign place 6 group=g2 line=22 name=sign1 file=' . fname
+  sign place 5 line=10 name=sign1 file=Xsign
+  sign place 5 group=g1 line=11 name=sign1 file=Xsign
+  sign place 5 group=g2 line=12 name=sign1 file=Xsign
+  sign place 6 line=20 name=sign1 file=Xsign
+  sign place 6 group=g1 line=21 name=sign1 file=Xsign
+  sign place 6 group=g2 line=22 name=sign1 file=Xsign
   sign unplace 5 group=*
   let a = execute('sign place group=*')
   call assert_equal("\n--- Signs ---\nSigns for Xsign:\n" .
@@ -693,14 +699,14 @@
 	      \ "    line=22  id=6  group=g2  name=sign1 priority=10\n", a)
 
   " Remove all the signs from all the groups in all the files
-  exe 'sign place 5 line=10 name=sign1 file=' . fname
-  exe 'sign place 5 group=g1 line=11 name=sign1 file=' . fname
+  sign place 5 line=10 name=sign1 file=Xsign
+  sign place 5 group=g1 line=11 name=sign1 file=Xsign
   sign unplace * group=*
   let a = execute('sign place group=*')
   call assert_equal("\n--- Signs ---\n", a)
 
   " Error cases
-  call assert_fails("exe 'sign place 3 group= name=sign1 buffer=' . bnum", 'E474:')
+  call assert_fails("sign place 3 group= name=sign1 buffer=" . bnum, 'E474:')
 
   call delete("Xsign")
   call sign_unplace('*')
diff --git a/src/version.c b/src/version.c
index d53ffac..2452ae0 100644
--- a/src/version.c
+++ b/src/version.c
@@ -800,6 +800,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    632,
+/**/
     631,
 /**/
     630,