diff --git a/gcc/c/c-decl.cc b/gcc/c/c-decl.cc
index aa7f69d1b7b..c73d3107efb 100644
--- a/gcc/c/c-decl.cc
+++ b/gcc/c/c-decl.cc
@@ -5358,7 +5358,7 @@ one_element_array_type_p (const_tree type)
 {
   if (TREE_CODE (type) != ARRAY_TYPE)
     return false;
-  return integer_zerop (array_type_nelts (type));
+  return integer_zerop (array_type_nelts_minus_one (type));
 }
 
 /* Determine whether TYPE is a zero-length array type "[0]".  */
@@ -6306,15 +6306,15 @@ get_parm_array_spec (const struct c_parm *parm, tree attrs)
 	  for (tree type = parm->specs->type; TREE_CODE (type) == ARRAY_TYPE;
 	       type = TREE_TYPE (type))
 	    {
-	      tree nelts = array_type_nelts (type);
-	      if (error_operand_p (nelts))
+	      tree nelts_minus_one = array_type_nelts_minus_one (type);
+	      if (error_operand_p (nelts_minus_one))
 		return attrs;
-	      if (TREE_CODE (nelts) != INTEGER_CST)
+	      if (TREE_CODE (nelts_minus_one) != INTEGER_CST)
 		{
 		  /* Each variable VLA bound is represented by the dollar
 		     sign.  */
 		  spec += "$";
-		  tpbnds = tree_cons (NULL_TREE, nelts, tpbnds);
+		  tpbnds = tree_cons (NULL_TREE, nelts_minus_one, tpbnds);
 		}
 	    }
 	  tpbnds = nreverse (tpbnds);
diff --git a/gcc/c/c-fold.cc b/gcc/c/c-fold.cc
index 57b67c74bd8..9ea174f79c4 100644
--- a/gcc/c/c-fold.cc
+++ b/gcc/c/c-fold.cc
@@ -73,11 +73,12 @@ c_fold_array_ref (tree type, tree ary, tree index)
   unsigned elem_nchars = (TYPE_PRECISION (elem_type)
 			  / TYPE_PRECISION (char_type_node));
   unsigned len = (unsigned) TREE_STRING_LENGTH (ary) / elem_nchars;
-  tree nelts = array_type_nelts (TREE_TYPE (ary));
+  tree nelts_minus_one = array_type_nelts_minus_one (TREE_TYPE (ary));
   bool dummy1 = true, dummy2 = true;
-  nelts = c_fully_fold_internal (nelts, true, &dummy1, &dummy2, false, false);
+  nelts_minus_one = c_fully_fold_internal (nelts_minus_one, true, &dummy1,
+					   &dummy2, false, false);
   unsigned HOST_WIDE_INT i = tree_to_uhwi (index);
-  if (!tree_int_cst_le (index, nelts)
+  if (!tree_int_cst_le (index, nelts_minus_one)
       || i >= len
       || i + elem_nchars > len)
     return NULL_TREE;
diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
index 27e24ba70ab..21606701725 100644
--- a/gcc/config/aarch64/aarch64.cc
+++ b/gcc/config/aarch64/aarch64.cc
@@ -1084,7 +1084,7 @@ pure_scalable_type_info::analyze_array (const_tree type)
 
   /* An array of unknown, flexible or variable length will be passed and
      returned by reference whatever we do.  */
-  tree nelts_minus_one = array_type_nelts (type);
+  tree nelts_minus_one = array_type_nelts_minus_one (type);
   if (!tree_fits_uhwi_p (nelts_minus_one))
     return DOESNT_MATTER;
 
diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
index 546c964d2a4..c6407843fc5 100644
--- a/gcc/config/i386/i386.cc
+++ b/gcc/config/i386/i386.cc
@@ -24393,7 +24393,7 @@ ix86_canonical_va_list_type (tree type)
 	return ms_va_list_type_node;
 
       if ((TREE_CODE (type) == ARRAY_TYPE
-	   && integer_zerop (array_type_nelts (type)))
+	   && integer_zerop (array_type_nelts_minus_one (type)))
 	  || POINTER_TYPE_P (type))
 	{
 	  tree elem_type = TREE_TYPE (type);
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 6458e96bded..98133894c48 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -6908,7 +6908,7 @@ reshape_init_array (tree type, reshape_iter *d, tree first_initializer_p,
   gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
 
   if (TYPE_DOMAIN (type))
-    max_index = array_type_nelts (type);
+    max_index = array_type_nelts_minus_one (type);
 
   return reshape_init_array_1 (TREE_TYPE (type), max_index, d,
 			       first_initializer_p, complain);
diff --git a/gcc/cp/init.cc b/gcc/cp/init.cc
index 20373d26988..493e64691cd 100644
--- a/gcc/cp/init.cc
+++ b/gcc/cp/init.cc
@@ -263,7 +263,7 @@ build_zero_init_1 (tree type, tree nelts, bool static_storage_p,
       else if (TYPE_DOMAIN (type) == NULL_TREE)
 	return NULL_TREE;
       else
-	max_index = array_type_nelts (type);
+	max_index = array_type_nelts_minus_one (type);
 
       /* If we have an error_mark here, we should just return error mark
 	 as we don't know the size of the array yet.  */
@@ -474,7 +474,7 @@ build_value_init_noctor (tree type, tsubst_flags_t complain)
       vec<constructor_elt, va_gc> *v = NULL;
 
       /* Iterate over the array elements, building initializations.  */
-      tree max_index = array_type_nelts (type);
+      tree max_index = array_type_nelts_minus_one (type);
 
       /* If we have an error_mark here, we should just return error mark
 	 as we don't know the size of the array yet.  */
@@ -4519,7 +4519,7 @@ build_vec_init (tree base, tree maxindex, tree init,
 		    : location_of (base));
 
   if (TREE_CODE (atype) == ARRAY_TYPE && TYPE_DOMAIN (atype))
-    maxindex = array_type_nelts (atype);
+    maxindex = array_type_nelts_minus_one (atype);
 
   if (maxindex == NULL_TREE || maxindex == error_mark_node)
     return error_mark_node;
@@ -5178,7 +5178,7 @@ build_delete (location_t loc, tree otype, tree addr,
 	    error_at (loc, "unknown array size in delete");
 	  return error_mark_node;
 	}
-      return build_vec_delete (loc, addr, array_type_nelts (type),
+      return build_vec_delete (loc, addr, array_type_nelts_minus_one (type),
 			       auto_delete, use_global_delete, complain);
     }
 
diff --git a/gcc/cp/lambda.cc b/gcc/cp/lambda.cc
index 0770417810e..065113bc122 100644
--- a/gcc/cp/lambda.cc
+++ b/gcc/cp/lambda.cc
@@ -556,7 +556,8 @@ add_capture (tree lambda, tree id, tree orig_init, bool by_reference_p,
 				     integer_zero_node, tf_warning_or_error);
       initializer = build_constructor_va (init_list_type_node, 2,
 					  NULL_TREE, build_address (elt),
-					  NULL_TREE, array_type_nelts (type));
+					  NULL_TREE,
+					  array_type_nelts_minus_one (type));
       type = vla_capture_type (type);
     }
   else if (!dependent_type_p (type)
diff --git a/gcc/cp/tree.cc b/gcc/cp/tree.cc
index 31ecbb1ac79..040136c70ab 100644
--- a/gcc/cp/tree.cc
+++ b/gcc/cp/tree.cc
@@ -3088,7 +3088,7 @@ array_type_nelts_top (tree type)
 {
   return fold_build2_loc (input_location,
 		      PLUS_EXPR, sizetype,
-		      array_type_nelts (type),
+		      array_type_nelts_minus_one (type),
 		      size_one_node);
 }
 
diff --git a/gcc/expr.cc b/gcc/expr.cc
index 320be8b17a1..803da754be1 100644
--- a/gcc/expr.cc
+++ b/gcc/expr.cc
@@ -6991,14 +6991,14 @@ count_type_elements (const_tree type, bool for_ctor_p)
     {
     case ARRAY_TYPE:
       {
-	tree nelts;
+	tree nelts_minus_one;
 
-	nelts = array_type_nelts (type);
-	if (nelts && tree_fits_uhwi_p (nelts))
+	nelts_minus_one = array_type_nelts_minus_one (type);
+	if (nelts_minus_one && tree_fits_uhwi_p (nelts_minus_one))
 	  {
 	    unsigned HOST_WIDE_INT n;
 
-	    n = tree_to_uhwi (nelts) + 1;
+	    n = tree_to_uhwi (nelts_minus_one) + 1;
 	    if (n == 0 || for_ctor_p)
 	      return n;
 	    else
diff --git a/gcc/fortran/trans-array.cc b/gcc/fortran/trans-array.cc
index 8c35926436d..22ac3c1a5f3 100644
--- a/gcc/fortran/trans-array.cc
+++ b/gcc/fortran/trans-array.cc
@@ -9640,7 +9640,7 @@ structure_alloc_comps (gfc_symbol * der_type, tree decl, tree dest,
       else
 	{
 	  /*  Otherwise use the TYPE_DOMAIN information.  */
-	  tmp = array_type_nelts (decl_type);
+	  tmp = array_type_nelts_minus_one (decl_type);
 	  tmp = fold_convert (gfc_array_index_type, tmp);
 	}
 
diff --git a/gcc/fortran/trans-openmp.cc b/gcc/fortran/trans-openmp.cc
index df1bf144e23..14cd2f9fad7 100644
--- a/gcc/fortran/trans-openmp.cc
+++ b/gcc/fortran/trans-openmp.cc
@@ -582,7 +582,7 @@ gfc_walk_alloc_comps (tree decl, tree dest, tree var,
 	      tem = size_binop (MINUS_EXPR, tem, size_one_node);
 	    }
 	  else
-	    tem = array_type_nelts (type);
+	    tem = array_type_nelts_minus_one (type);
 	  tem = fold_convert (gfc_array_index_type, tem);
 	}
 
@@ -1309,7 +1309,7 @@ gfc_omp_clause_linear_ctor (tree clause, tree dest, tree src, tree add)
 	  nelems = size_binop (MINUS_EXPR, nelems, size_one_node);
 	}
       else
-	nelems = array_type_nelts (type);
+	nelems = array_type_nelts_minus_one (type);
       nelems = fold_convert (gfc_array_index_type, nelems);
 
       gfc_omp_linear_clause_add_loop (&block, dest, src, add, nelems);
diff --git a/gcc/rust/backend/rust-tree.cc b/gcc/rust/backend/rust-tree.cc
index cdb79095da8..8d32e5203ae 100644
--- a/gcc/rust/backend/rust-tree.cc
+++ b/gcc/rust/backend/rust-tree.cc
@@ -869,7 +869,7 @@ tree
 array_type_nelts_top (tree type)
 {
   return fold_build2_loc (input_location, PLUS_EXPR, sizetype,
-			  array_type_nelts (type), size_one_node);
+			  array_type_nelts_minus_one (type), size_one_node);
 }
 
 // forked from gcc/cp/tree.cc builtin_valid_in_constant_expr_p
diff --git a/gcc/tree.cc b/gcc/tree.cc
index b14cfbe7929..7439777f307 100644
--- a/gcc/tree.cc
+++ b/gcc/tree.cc
@@ -3698,7 +3698,7 @@ int_byte_position (const_tree field)
    ARRAY_TYPE) minus one.  This counts only elements of the top array.  */
 
 tree
-array_type_nelts (const_tree type)
+array_type_nelts_minus_one (const_tree type)
 {
   tree index_type, min, max;
 
@@ -14789,7 +14789,7 @@ is_empty_type (const_tree type)
       return true;
     }
   else if (TREE_CODE (type) == ARRAY_TYPE)
-    return (integer_minus_onep (array_type_nelts (type))
+    return (integer_minus_onep (array_type_nelts_minus_one (type))
 	    || TYPE_DOMAIN (type) == NULL_TREE
 	    || is_empty_type (TREE_TYPE (type)));
   return false;
diff --git a/gcc/tree.h b/gcc/tree.h
index 93aa7d22d6f..4e29544a36c 100644
--- a/gcc/tree.h
+++ b/gcc/tree.h
@@ -4921,7 +4921,7 @@ extern tree build_method_type_directly (tree, tree, tree);
 extern tree build_method_type (tree, tree);
 extern tree build_offset_type (tree, tree);
 extern tree build_complex_type (tree, bool named = false);
-extern tree array_type_nelts (const_tree);
+extern tree array_type_nelts_minus_one (const_tree);
 
 extern tree value_member (tree, tree);
 extern tree purpose_member (const_tree, tree);
