diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
index 88401a2a00b..a5e26b746fb 100644
--- a/gcc/tree-vect-stmts.cc
+++ b/gcc/tree-vect-stmts.cc
@@ -13297,14 +13297,14 @@ get_related_vectype_for_scalar_type (machine_mode prevailing_mode,
 
 tree
 get_vectype_for_scalar_type (vec_info *vinfo, tree scalar_type,
-			     unsigned int group_size)
+			     poly_uint64 group_size)
 {
   /* For BB vectorization, we should always have a group size once we've
      constructed the SLP tree; the only valid uses of zero GROUP_SIZEs
      are tentative requests during things like early data reference
      analysis and pattern recognition.  */
   if (is_a <bb_vec_info> (vinfo))
-    gcc_assert (vinfo->slp_instances.is_empty () || group_size != 0);
+    gcc_assert (vinfo->slp_instances.is_empty () || known_ne (group_size, 0));
   else
     group_size = 0;
 
@@ -13320,9 +13320,11 @@ get_vectype_for_scalar_type (vec_info *vinfo, tree scalar_type,
 
   /* If the natural choice of vector type doesn't satisfy GROUP_SIZE,
      try again with an explicit number of elements.  */
+  uint64_t cst_group_size;
   if (vectype
-      && group_size
-      && maybe_ge (TYPE_VECTOR_SUBPARTS (vectype), group_size))
+      && group_size.is_constant (&cst_group_size)
+      && cst_group_size != 0
+      && maybe_ge (TYPE_VECTOR_SUBPARTS (vectype), cst_group_size))
     {
       /* Start with the biggest number of units that fits within
 	 GROUP_SIZE and halve it until we find a valid vector type.
@@ -13336,7 +13338,7 @@ get_vectype_for_scalar_type (vec_info *vinfo, tree scalar_type,
 	 even though the group is not a multiple of that vector size.
 	 The BB vectorizer will then try to carve up the group into
 	 smaller pieces.  */
-      unsigned int nunits = 1 << floor_log2 (group_size);
+      unsigned int nunits = 1 << floor_log2 (cst_group_size);
       do
 	{
 	  vectype = get_related_vectype_for_scalar_type (vinfo->vector_mode,
@@ -13372,7 +13374,7 @@ get_vectype_for_scalar_type (vec_info *vinfo, tree scalar_type, slp_tree node)
 
 tree
 get_mask_type_for_scalar_type (vec_info *vinfo, tree scalar_type,
-			       unsigned int group_size)
+			       poly_uint64 group_size)
 {
   tree vectype = get_vectype_for_scalar_type (vinfo, scalar_type, group_size);
 
@@ -14243,7 +14245,7 @@ opt_result
 vect_get_vector_types_for_stmt (vec_info *vinfo, stmt_vec_info stmt_info,
 				tree *stmt_vectype_out,
 				tree *nunits_vectype_out,
-				unsigned int group_size)
+				poly_uint64 group_size)
 {
   gimple *stmt = stmt_info->stmt;
 
@@ -14252,7 +14254,7 @@ vect_get_vector_types_for_stmt (vec_info *vinfo, stmt_vec_info stmt_info,
      are tentative requests during things like early data reference
      analysis and pattern recognition.  */
   if (is_a <bb_vec_info> (vinfo))
-    gcc_assert (vinfo->slp_instances.is_empty () || group_size != 0);
+    gcc_assert (vinfo->slp_instances.is_empty () || known_ne (group_size, 0));
   else
     group_size = 0;
 
@@ -14281,7 +14283,7 @@ vect_get_vector_types_for_stmt (vec_info *vinfo, stmt_vec_info stmt_info,
 
   tree vectype;
   tree scalar_type = NULL_TREE;
-  if (group_size == 0 && STMT_VINFO_VECTYPE (stmt_info))
+  if (known_eq (group_size, 0U) && STMT_VINFO_VECTYPE (stmt_info))
     {
       vectype = STMT_VINFO_VECTYPE (stmt_info);
       if (dump_enabled_p ())
@@ -14310,10 +14312,11 @@ vect_get_vector_types_for_stmt (vec_info *vinfo, stmt_vec_info stmt_info,
 
       if (dump_enabled_p ())
 	{
-	  if (group_size)
+	  if (known_ne (group_size, 0U))
 	    dump_printf_loc (MSG_NOTE, vect_location,
 			     "get vectype for scalar type (group size %d):"
-			     " %T\n", group_size, scalar_type);
+			     " %T\n", (int)constant_lower_bound (group_size),
+			     scalar_type);
 	  else
 	    dump_printf_loc (MSG_NOTE, vect_location,
 			     "get vectype for scalar type: %T\n", scalar_type);
diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h
index a2bab8676af..95240504d18 100644
--- a/gcc/tree-vectorizer.h
+++ b/gcc/tree-vectorizer.h
@@ -2204,9 +2204,9 @@ extern edge vec_init_loop_exit_info (class loop *);
 /* In tree-vect-stmts.cc.  */
 extern tree get_related_vectype_for_scalar_type (machine_mode, tree,
 						 poly_uint64 = 0);
-extern tree get_vectype_for_scalar_type (vec_info *, tree, unsigned int = 0);
+extern tree get_vectype_for_scalar_type (vec_info *, tree, poly_uint64 = 0);
 extern tree get_vectype_for_scalar_type (vec_info *, tree, slp_tree);
-extern tree get_mask_type_for_scalar_type (vec_info *, tree, unsigned int = 0);
+extern tree get_mask_type_for_scalar_type (vec_info *, tree, poly_uint64 = 0);
 extern tree get_mask_type_for_scalar_type (vec_info *, tree, slp_tree);
 extern tree get_same_sized_vectype (tree, tree);
 extern bool vect_chooses_same_modes_p (vec_info *, machine_mode);
@@ -2295,8 +2295,7 @@ extern tree vect_gen_while (gimple_seq *, tree, tree, tree,
 extern tree vect_gen_while_not (gimple_seq *, tree, tree, tree);
 extern opt_result vect_get_vector_types_for_stmt (vec_info *,
 						  stmt_vec_info, tree *,
-						  tree *, unsigned int = 0);
-extern opt_tree vect_get_mask_type_for_stmt (stmt_vec_info, unsigned int = 0);
+						  tree *, poly_uint64 = 0);
 
 /* In tree-vect-data-refs.cc.  */
 extern bool vect_can_force_dr_alignment_p (const_tree, poly_uint64);
