glsl: Make ir_validate check the type of ir_discard::condition.

Copy and pasted from the ir_if::condition handling, plus a NULL check.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Eric Anholt <eric@anholt.net>

src/glsl/ir_validate.cpp

@@ -61,6 +61,7 @@ public:
    virtual ir_visitor_status visit(ir_variable *v);
    virtual ir_visitor_status visit(ir_dereference_variable *ir);
 
+   virtual ir_visitor_status visit_enter(ir_discard *ir);
    virtual ir_visitor_status visit_enter(ir_if *ir);
 
    virtual ir_visitor_status visit_enter(ir_function *ir);
@@ -132,6 +133,20 @@ ir_validate::visit_enter(class ir_dereference_array *ir)
    return visit_continue;
 }
 
+ir_visitor_status
+ir_validate::visit_enter(ir_discard *ir)
+{
+   if (ir->condition && ir->condition->type != glsl_type::bool_type) {
+      printf("ir_discard condition %s type instead of bool.\n",
+	     ir->condition->type->name);
+      ir->print();
+      printf("\n");
+      abort();
+   }
+
+   return visit_continue;
+}
+
 ir_visitor_status
 ir_validate::visit_enter(ir_if *ir)
 {