diff --git a/src/compiler/nir/nir_lower_io_to_vector.c b/src/compiler/nir/nir_lower_io_to_vector.c
index e17f6ddb158..27913b507e9 100644
--- a/src/compiler/nir/nir_lower_io_to_vector.c
+++ b/src/compiler/nir/nir_lower_io_to_vector.c
@@ -304,7 +304,8 @@ create_new_io_vars(nir_shader *shader, nir_variable_mode mode,
             var->type = flat_type;
 
          nir_shader_add_variable(shader, var);
-         for (unsigned i = 0; i < glsl_get_length(flat_type); i++) {
+         unsigned num_slots = MAX2(glsl_get_length(flat_type), 1);
+         for (unsigned i = 0; i < num_slots; i++) {
             for (unsigned j = 0; j < 4; j++)
                new_vars[loc + i][j] = var;
             flat_vars[loc + i] = true;