diff --git a/src/compiler/nir/nir_linking_helpers.c b/src/compiler/nir/nir_linking_helpers.c
index ce987c31886..af34fbc213f 100644
--- a/src/compiler/nir/nir_linking_helpers.c
+++ b/src/compiler/nir/nir_linking_helpers.c
@@ -32,8 +32,8 @@
  */
 
 /**
- * Returns the bits in the inputs_read, outputs_written, or
- * system_values_read bitfield corresponding to this variable.
+ * Returns the bits in the inputs_read, or outputs_written
+ * bitfield corresponding to this variable.
  */
 static uint64_t
 get_variable_io_mask(nir_variable *var, gl_shader_stage stage)
@@ -45,8 +45,7 @@ get_variable_io_mask(nir_variable *var, gl_shader_stage stage)
       var->data.location - VARYING_SLOT_PATCH0 : var->data.location;
 
    assert(var->data.mode == nir_var_shader_in ||
-          var->data.mode == nir_var_shader_out ||
-          var->data.mode == nir_var_system_value);
+          var->data.mode == nir_var_shader_out);
    assert(var->data.location >= 0);
 
    const struct glsl_type *type = var->type;