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]>

9 files changed, 81 insertions, 0 deletions

diff --git a/src/compiler/glsl/glsl_to_nir.cpp b/src/compiler/glsl/glsl_to_nir.cpp
index 1e096a66c20..883cfb57601 100644
--- a/src/compiler/glsl/glsl_to_nir.cpp
+++ b/src/compiler/glsl/glsl_to_nir.cpp
@@ -63,6 +63,7 @@ public:
    virtual void visit(ir_loop *);
    virtual void visit(ir_if *);
    virtual void visit(ir_discard *);
+   virtual void visit(ir_demote *);
    virtual void visit(ir_loop_jump *);
    virtual void visit(ir_return *);
    virtual void visit(ir_call *);
@@ -776,6 +777,15 @@ nir_visitor::visit(ir_discard *ir)
 }
 
 void
+nir_visitor::visit(ir_demote *ir)
+{
+   nir_intrinsic_instr *demote =
+      nir_intrinsic_instr_create(this->shader, nir_intrinsic_demote);
+
+   nir_builder_instr_insert(&b, &demote->instr);
+}
+
+void
 nir_visitor::visit(ir_emit_vertex *ir)
 {
    nir_intrinsic_instr *instr =
diff --git a/src/compiler/glsl/ir.h b/src/compiler/glsl/ir.h
index ba831f2c1ed..e3c28bbb2b8 100644
--- a/src/compiler/glsl/ir.h
+++ b/src/compiler/glsl/ir.h
@@ -74,6 +74,7 @@ enum ir_node_type {
    ir_type_loop_jump,
    ir_type_return,
    ir_type_discard,
+   ir_type_demote,
    ir_type_emit_vertex,
    ir_type_end_primitive,
    ir_type_barrier,
@@ -1805,6 +1806,28 @@ public:
 
 
 /**
+ * IR instruction representing demote statements from
+ * GL_EXT_demote_to_helper_invocation.
+ */
+class ir_demote : public ir_instruction {
+public:
+   ir_demote()
+      : ir_instruction(ir_type_demote)
+   {
+   }
+
+   virtual ir_demote *clone(void *mem_ctx, struct hash_table *ht) const;
+
+   virtual void accept(ir_visitor *v)
+   {
+      v->visit(this);
+   }
+
+   virtual ir_visitor_status accept(ir_hierarchical_visitor *);
+};
+
+
+/**
  * Texture sampling opcodes used in ir_texture
  */
 enum ir_texture_opcode {
diff --git a/src/compiler/glsl/ir_clone.cpp b/src/compiler/glsl/ir_clone.cpp
index c492fdbb3d0..eb24ffe9be2 100644
--- a/src/compiler/glsl/ir_clone.cpp
+++ b/src/compiler/glsl/ir_clone.cpp
@@ -102,6 +102,12 @@ ir_discard::clone(void *mem_ctx, struct hash_table *ht) const
    return new(mem_ctx) ir_discard(new_condition);
 }
 
+ir_demote *
+ir_demote::clone(void *mem_ctx, struct hash_table *ht) const
+{
+   return new(mem_ctx) ir_demote();
+}
+
 ir_loop_jump *
 ir_loop_jump::clone(void *mem_ctx, struct hash_table *ht) const
 {
diff --git a/src/compiler/glsl/ir_hierarchical_visitor.cpp b/src/compiler/glsl/ir_hierarchical_visitor.cpp
index 1d23a776643..8fcf48e2bb4 100644
--- a/src/compiler/glsl/ir_hierarchical_visitor.cpp
+++ b/src/compiler/glsl/ir_hierarchical_visitor.cpp
@@ -305,6 +305,24 @@ ir_hierarchical_visitor::visit_leave(ir_discard *ir)
 }
 
 ir_visitor_status
+ir_hierarchical_visitor::visit_enter(ir_demote *ir)
+{
+   if (this->callback_enter != NULL)
+      this->callback_enter(ir, this->data_enter);
+
+   return visit_continue;
+}
+
+ir_visitor_status
+ir_hierarchical_visitor::visit_leave(ir_demote *ir)
+{
+   if (this->callback_leave != NULL)
+      this->callback_leave(ir, this->data_leave);
+
+   return visit_continue;
+}
+
+ir_visitor_status
 ir_hierarchical_visitor::visit_enter(ir_if *ir)
 {
    if (this->callback_enter != NULL)
diff --git a/src/compiler/glsl/ir_hierarchical_visitor.h b/src/compiler/glsl/ir_hierarchical_visitor.h
index 5f5acd041b8..e10bb7c60db 100644
--- a/src/compiler/glsl/ir_hierarchical_visitor.h
+++ b/src/compiler/glsl/ir_hierarchical_visitor.h
@@ -133,6 +133,8 @@ public:
    virtual ir_visitor_status visit_leave(class ir_return *);
    virtual ir_visitor_status visit_enter(class ir_discard *);
    virtual ir_visitor_status visit_leave(class ir_discard *);
+   virtual ir_visitor_status visit_enter(class ir_demote *);
+   virtual ir_visitor_status visit_leave(class ir_demote *);
    virtual ir_visitor_status visit_enter(class ir_if *);
    virtual ir_visitor_status visit_leave(class ir_if *);
    virtual ir_visitor_status visit_enter(class ir_emit_vertex *);
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);
diff --git a/src/compiler/glsl/ir_print_visitor.cpp b/src/compiler/glsl/ir_print_visitor.cpp
index b3a62ce38bd..2eaebb21d47 100644
--- a/src/compiler/glsl/ir_print_visitor.cpp
+++ b/src/compiler/glsl/ir_print_visitor.cpp
@@ -565,6 +565,13 @@ ir_print_visitor::visit(ir_discard *ir)
 
 
 void
+ir_print_visitor::visit(ir_demote *ir)
+{
+   fprintf(f, "(demote)");
+}
+
+
+void
 ir_print_visitor::visit(ir_if *ir)
 {
    fprintf(f, "(if ");
diff --git a/src/compiler/glsl/ir_print_visitor.h b/src/compiler/glsl/ir_print_visitor.h
index 652cd90bc00..a71e1aba886 100644
--- a/src/compiler/glsl/ir_print_visitor.h
+++ b/src/compiler/glsl/ir_print_visitor.h
@@ -63,6 +63,7 @@ public:
    virtual void visit(ir_call *);
    virtual void visit(ir_return *);
    virtual void visit(ir_discard *);
+   virtual void visit(ir_demote *);
    virtual void visit(ir_if *);
    virtual void visit(ir_loop *);
    virtual void visit(ir_loop_jump *);
diff --git a/src/compiler/glsl/ir_visitor.h b/src/compiler/glsl/ir_visitor.h
index 117b5bc6ae8..b06e310ffd7 100644
--- a/src/compiler/glsl/ir_visitor.h
+++ b/src/compiler/glsl/ir_visitor.h
@@ -59,6 +59,7 @@ public:
    virtual void visit(class ir_call *) = 0;
    virtual void visit(class ir_return *) = 0;
    virtual void visit(class ir_discard *) = 0;
+   virtual void visit(class ir_demote *) = 0;
    virtual void visit(class ir_if *) = 0;
    virtual void visit(class ir_loop *) = 0;
    virtual void visit(class ir_loop_jump *) = 0;
@@ -83,6 +84,7 @@ public:
    virtual void visit(class ir_assignment *) {}
    virtual void visit(class ir_constant *) {}
    virtual void visit(class ir_call *) {}
+   virtual void visit(class ir_demote *) {}
    virtual void visit(class ir_emit_vertex *) {}
    virtual void visit(class ir_end_primitive *) {}
    virtual void visit(class ir_barrier *) {}