glsl: Add ir_demote

To represent the new `demote` keyword when using
EXT_demote_to_helper_invocation extension.  Most of the changes are to
include it in the visitors.

Demote is not considered a control flow, so also include an empty
visit member function in ir_control_flow_visitor.

Only NIR actually supports `demote`, so assert the translations for
TGSI and Mesa's gl_program -- since the demote is not expected to
appear for those.

Reviewed-by: Kenneth Graunke <[email protected]>

1 files changed, 12 insertions, 0 deletions

diff --git a/src/compiler/glsl/ir_hv_accept.cpp b/src/compiler/glsl/ir_hv_accept.cpp
index f04a5b6fd19..6e5e25378e1 100644
--- a/src/compiler/glsl/ir_hv_accept.cpp
+++ b/src/compiler/glsl/ir_hv_accept.cpp
@@ -379,6 +379,18 @@ ir_discard::accept(ir_hierarchical_visitor *v)
 
 
 ir_visitor_status
+ir_demote::accept(ir_hierarchical_visitor *v)
+{
+   ir_visitor_status s = v->visit_enter(this);
+
+   if (s != visit_continue)
+      return (s == visit_continue_with_parent) ? visit_continue : s;
+
+   return v->visit_leave(this);
+}
+
+
+ir_visitor_status
 ir_if::accept(ir_hierarchical_visitor *v)
 {
    ir_visitor_status s = v->visit_enter(this);