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authorEric Anholt <eric@anholt.net>2010-08-22 18:15:20 -0700
committerEric Anholt <eric@anholt.net>2010-08-22 18:34:46 -0700
commit6606fde3ec18288ecc4c6ce6d3fd32224a6c5248 (patch)
tree125413c14e7620e665b21c71d668df240d145c3d
parent137b8397fa5cc5d70e86a4b14d6be9326340f584 (diff)
glsl: Convert constant folding to the rvalue visitor.
This should be mostly a noop, except that a plain dereference of a variable that is not part of a constant expression could now get "constant folded". I expect that for all current backends this will be either a noop, or possibly a win when it provokes more ir_algebraic. It'll also ensure that when new features are added, tree walking will work normally. Before this, constants weren't getting folded inside of loops.
-rw-r--r--src/glsl/ir_constant_folding.cpp200
1 files changed, 19 insertions, 181 deletions
diff --git a/src/glsl/ir_constant_folding.cpp b/src/glsl/ir_constant_folding.cpp
index 11260423d90..90135b5807a 100644
--- a/src/glsl/ir_constant_folding.cpp
+++ b/src/glsl/ir_constant_folding.cpp
@@ -28,6 +28,7 @@
#include "ir.h"
#include "ir_visitor.h"
+#include "ir_rvalue_visitor.h"
#include "ir_optimization.h"
#include "glsl_types.h"
@@ -35,7 +36,7 @@
* Visitor class for replacing expressions with ir_constant values.
*/
-class ir_constant_folding_visitor : public ir_visitor {
+class ir_constant_folding_visitor : public ir_rvalue_visitor {
public:
ir_constant_folding_visitor()
{
@@ -47,40 +48,15 @@ public:
/* empty */
}
- /**
- * \name Visit methods
- *
- * As typical for the visitor pattern, there must be one \c visit method for
- * each concrete subclass of \c ir_instruction. Virtual base classes within
- * the hierarchy should not have \c visit methods.
- */
- /*@{*/
- virtual void visit(ir_variable *);
- virtual void visit(ir_function_signature *);
- virtual void visit(ir_function *);
- virtual void visit(ir_expression *);
- virtual void visit(ir_texture *);
- virtual void visit(ir_swizzle *);
- virtual void visit(ir_dereference_variable *);
- virtual void visit(ir_dereference_array *);
- virtual void visit(ir_dereference_record *);
- virtual void visit(ir_assignment *);
- virtual void visit(ir_constant *);
- virtual void visit(ir_call *);
- virtual void visit(ir_return *);
- virtual void visit(ir_discard *);
- virtual void visit(ir_if *);
- virtual void visit(ir_loop *);
- virtual void visit(ir_loop_jump *);
- /*@}*/
+ virtual ir_visitor_status visit_enter(ir_assignment *ir);
- void fold_constant(ir_rvalue **rvalue);
+ virtual void handle_rvalue(ir_rvalue **rvalue);
bool progress;
};
void
-ir_constant_folding_visitor::fold_constant(ir_rvalue **rvalue)
+ir_constant_folding_visitor::handle_rvalue(ir_rvalue **rvalue)
{
if (*rvalue == NULL || (*rvalue)->ir_type == ir_type_constant)
return;
@@ -94,104 +70,20 @@ ir_constant_folding_visitor::fold_constant(ir_rvalue **rvalue)
}
}
-void
-ir_constant_folding_visitor::visit(ir_variable *ir)
-{
- (void) ir;
-}
-
-
-void
-ir_constant_folding_visitor::visit(ir_function_signature *ir)
-{
- visit_exec_list(&ir->body, this);
-}
-
-
-void
-ir_constant_folding_visitor::visit(ir_function *ir)
-{
- foreach_iter(exec_list_iterator, iter, *ir) {
- ir_function_signature *const sig = (ir_function_signature *) iter.get();
- sig->accept(this);
- }
-}
-
-void
-ir_constant_folding_visitor::visit(ir_expression *ir)
-{
- unsigned int operand;
-
- for (operand = 0; operand < ir->get_num_operands(); operand++) {
- fold_constant(&ir->operands[operand]);
- }
-}
-
-
-void
-ir_constant_folding_visitor::visit(ir_texture *ir)
-{
- fold_constant(&ir->coordinate);
- fold_constant(&ir->projector);
- fold_constant(&ir->shadow_comparitor);
-
- switch (ir->op) {
- case ir_tex:
- break;
- case ir_txb:
- fold_constant(&ir->lod_info.bias);
- break;
- case ir_txf:
- case ir_txl:
- fold_constant(&ir->lod_info.lod);
- break;
- case ir_txd:
- fold_constant(&ir->lod_info.grad.dPdx);
- fold_constant(&ir->lod_info.grad.dPdy);
- break;
- }
-}
-
-
-void
-ir_constant_folding_visitor::visit(ir_swizzle *ir)
+ir_visitor_status
+ir_constant_folding_visitor::visit_enter(ir_assignment *ir)
{
- fold_constant(&ir->val);
-}
-
-
-void
-ir_constant_folding_visitor::visit(ir_dereference_variable *ir)
-{
- (void) ir;
-}
-
-
-void
-ir_constant_folding_visitor::visit(ir_dereference_array *ir)
-{
- fold_constant(&ir->array_index);
- ir->array->accept(this);
-}
-
-
-void
-ir_constant_folding_visitor::visit(ir_dereference_record *ir)
-{
- ir->record->accept(this);
-}
-
-
-void
-ir_constant_folding_visitor::visit(ir_assignment *ir)
-{
- fold_constant(&ir->rhs);
+ ir->rhs->accept(this);
+ handle_rvalue(&ir->rhs);
if (ir->condition) {
+ ir->condition->accept(this);
+ handle_rvalue(&ir->condition);
+
+ ir_constant *const_val = ir->condition->as_constant();
/* If the condition is constant, either remove the condition or
* remove the never-executed assignment.
*/
- ir_constant *const_val = ir->condition->constant_expression_value();
if (const_val) {
if (const_val->value.b[0])
ir->condition = NULL;
@@ -200,66 +92,12 @@ ir_constant_folding_visitor::visit(ir_assignment *ir)
this->progress = true;
}
}
-}
-
-
-void
-ir_constant_folding_visitor::visit(ir_constant *ir)
-{
- (void) ir;
-}
-
-void
-ir_constant_folding_visitor::visit(ir_call *ir)
-{
- foreach_iter(exec_list_iterator, iter, *ir) {
- ir_rvalue *param = (ir_rvalue *)iter.get();
- ir_rvalue *new_param = param;
- fold_constant(&new_param);
-
- if (new_param != param) {
- param->replace_with(new_param);
- }
- }
-}
-
-
-void
-ir_constant_folding_visitor::visit(ir_return *ir)
-{
- fold_constant(&ir->value);
-}
-
-
-void
-ir_constant_folding_visitor::visit(ir_discard *ir)
-{
- (void) ir;
-}
-
-
-void
-ir_constant_folding_visitor::visit(ir_if *ir)
-{
- fold_constant(&ir->condition);
-
- visit_exec_list(&ir->then_instructions, this);
- visit_exec_list(&ir->else_instructions, this);
-}
-
-
-void
-ir_constant_folding_visitor::visit(ir_loop *ir)
-{
- (void) ir;
-}
-
-
-void
-ir_constant_folding_visitor::visit(ir_loop_jump *ir)
-{
- (void) ir;
+ /* Don't descend into the LHS because we want it to stay as a
+ * variable dereference. FINISHME: We probably should to get array
+ * indices though.
+ */
+ return visit_continue_with_parent;
}
bool
@@ -267,7 +105,7 @@ do_constant_folding(exec_list *instructions)
{
ir_constant_folding_visitor constant_folding;
- visit_exec_list(instructions, &constant_folding);
+ visit_list_elements(&constant_folding, instructions);
return constant_folding.progress;
}