glsl: don't try adding built-ins to explicit locations bitmask

Reviewed-by: Anuj Phogat <anuj.phogat@gmail.com>
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>

diff --git a/src/glsl/link_varyings.cpp b/src/glsl/link_varyings.cpp
index 1da0c9e..8763cc5 100644 (file)
--- a/src/glsl/link_varyings.cpp
+++ b/src/glsl/link_varyings.cpp
@@ -1518,7 +1518,9 @@ reserved_varying_slot(struct gl_shader *stage, ir_variable_mode io_mode)
    foreach_in_list(ir_instruction, node, stage->ir) {
       ir_variable *const var = node->as_variable();
 
-      if (var == NULL || var->data.mode != io_mode || !var->data.explicit_location)
+      if (var == NULL || var->data.mode != io_mode ||
+          !var->data.explicit_location ||
+          var->data.location < VARYING_SLOT_VAR0)
          continue;
 
       var_slot = var->data.location - VARYING_SLOT_VAR0;