#include "glsl_types.h"
#include "ir.h"
+#include "program/hash_table.h"
+
+namespace {
class ir_if_to_cond_assign_visitor : public ir_hierarchical_visitor {
public:
this->progress = false;
this->max_depth = max_depth;
this->depth = 0;
+
+ this->condition_variables = hash_table_ctor(0, hash_table_pointer_hash,
+ hash_table_pointer_compare);
+ }
+
+ ~ir_if_to_cond_assign_visitor()
+ {
+ hash_table_dtor(this->condition_variables);
}
ir_visitor_status visit_enter(ir_if *);
bool progress;
unsigned max_depth;
unsigned depth;
+
+ struct hash_table *condition_variables;
};
+} /* anonymous namespace */
+
bool
lower_if_to_cond_assign(exec_list *instructions, unsigned max_depth)
{
+ if (max_depth == UINT_MAX)
+ return false;
+
ir_if_to_cond_assign_visitor v(max_depth);
visit_list_elements(&v, instructions);
void
move_block_to_cond_assign(void *mem_ctx,
- ir_if *if_ir, ir_variable *cond_var, bool then)
+ ir_if *if_ir, ir_rvalue *cond_expr,
+ exec_list *instructions,
+ struct hash_table *ht)
{
- exec_list *instructions;
-
- if (then) {
- instructions = &if_ir->then_instructions;
- } else {
- instructions = &if_ir->else_instructions;
- }
-
- foreach_iter(exec_list_iterator, iter, *instructions) {
- ir_instruction *ir = (ir_instruction *)iter.get();
+ foreach_list_safe(node, instructions) {
+ ir_instruction *ir = (ir_instruction *) node;
if (ir->ir_type == ir_type_assignment) {
ir_assignment *assign = (ir_assignment *)ir;
- ir_rvalue *cond_expr;
- ir_dereference *deref = new(mem_ctx) ir_dereference_variable(cond_var);
-
- if (then) {
- cond_expr = deref;
- } else {
- cond_expr = new(mem_ctx) ir_expression(ir_unop_logic_not,
- glsl_type::bool_type,
- deref,
- NULL);
- }
- if (!assign->condition) {
- assign->condition = cond_expr;
- } else {
- assign->condition = new(mem_ctx) ir_expression(ir_binop_logic_and,
- glsl_type::bool_type,
- cond_expr,
- assign->condition);
+ if (hash_table_find(ht, assign) == NULL) {
+ hash_table_insert(ht, assign, assign);
+
+ /* If the LHS of the assignment is a condition variable that was
+ * previously added, insert an additional assignment of false to
+ * the variable.
+ */
+ const bool assign_to_cv =
+ hash_table_find(ht, assign->lhs->variable_referenced()) != NULL;
+
+ if (!assign->condition) {
+ if (assign_to_cv) {
+ assign->rhs =
+ new(mem_ctx) ir_expression(ir_binop_logic_and,
+ glsl_type::bool_type,
+ cond_expr->clone(mem_ctx, NULL),
+ assign->rhs);
+ } else {
+ assign->condition = cond_expr->clone(mem_ctx, NULL);
+ }
+ } else {
+ assign->condition =
+ new(mem_ctx) ir_expression(ir_binop_logic_and,
+ glsl_type::bool_type,
+ cond_expr->clone(mem_ctx, NULL),
+ assign->condition);
+ }
}
}
{
(void) ir;
this->depth++;
+
return visit_continue;
}
ir_if_to_cond_assign_visitor::visit_leave(ir_if *ir)
{
/* Only flatten when beyond the GPU's maximum supported nesting depth. */
- if (this->depth <= this->max_depth)
+ if (this->depth-- <= this->max_depth)
return visit_continue;
- this->depth--;
-
bool found_control_flow = false;
- ir_variable *cond_var;
ir_assignment *assign;
- ir_dereference_variable *deref;
/* Check that both blocks don't contain anything we can't support. */
- foreach_iter(exec_list_iterator, then_iter, ir->then_instructions) {
- ir_instruction *then_ir = (ir_instruction *)then_iter.get();
+ foreach_list(n, &ir->then_instructions) {
+ ir_instruction *then_ir = (ir_instruction *) n;
visit_tree(then_ir, check_control_flow, &found_control_flow);
}
- foreach_iter(exec_list_iterator, else_iter, ir->else_instructions) {
- ir_instruction *else_ir = (ir_instruction *)else_iter.get();
+ foreach_list(n, &ir->else_instructions) {
+ ir_instruction *else_ir = (ir_instruction *) n;
visit_tree(else_ir, check_control_flow, &found_control_flow);
}
if (found_control_flow)
return visit_continue;
- void *mem_ctx = talloc_parent(ir);
+ void *mem_ctx = ralloc_parent(ir);
- /* Store the condition to a variable so the assignment conditions are
- * simpler.
+ /* Store the condition to a variable. Move all of the instructions from
+ * the then-clause of the if-statement. Use the condition variable as a
+ * condition for all assignments.
*/
- cond_var = new(mem_ctx) ir_variable(glsl_type::bool_type,
- "if_to_cond_assign_condition",
- ir_var_temporary);
- ir->insert_before(cond_var);
-
- deref = new(mem_ctx) ir_dereference_variable(cond_var);
- assign = new(mem_ctx) ir_assignment(deref,
- ir->condition, NULL);
+ ir_variable *const then_var =
+ new(mem_ctx) ir_variable(glsl_type::bool_type,
+ "if_to_cond_assign_then",
+ ir_var_temporary);
+ ir->insert_before(then_var);
+
+ ir_dereference_variable *then_cond =
+ new(mem_ctx) ir_dereference_variable(then_var);
+
+ assign = new(mem_ctx) ir_assignment(then_cond, ir->condition);
ir->insert_before(assign);
- /* Now, move all of the instructions out of the if blocks, putting
- * conditions on assignments.
+ move_block_to_cond_assign(mem_ctx, ir, then_cond,
+ &ir->then_instructions,
+ this->condition_variables);
+
+ /* Add the new condition variable to the hash table. This allows us to
+ * find this variable when lowering other (enclosing) if-statements.
+ */
+ hash_table_insert(this->condition_variables, then_var, then_var);
+
+ /* If there are instructions in the else-clause, store the inverse of the
+ * condition to a variable. Move all of the instructions from the
+ * else-clause if the if-statement. Use the (inverse) condition variable
+ * as a condition for all assignments.
*/
- move_block_to_cond_assign(mem_ctx, ir, cond_var, true);
- move_block_to_cond_assign(mem_ctx, ir, cond_var, false);
+ if (!ir->else_instructions.is_empty()) {
+ ir_variable *const else_var =
+ new(mem_ctx) ir_variable(glsl_type::bool_type,
+ "if_to_cond_assign_else",
+ ir_var_temporary);
+ ir->insert_before(else_var);
+
+ ir_dereference_variable *else_cond =
+ new(mem_ctx) ir_dereference_variable(else_var);
+
+ ir_rvalue *inverse =
+ new(mem_ctx) ir_expression(ir_unop_logic_not,
+ then_cond->clone(mem_ctx, NULL));
+
+ assign = new(mem_ctx) ir_assignment(else_cond, inverse);
+ ir->insert_before(assign);
+
+ move_block_to_cond_assign(mem_ctx, ir, else_cond,
+ &ir->else_instructions,
+ this->condition_variables);
+
+ /* Add the new condition variable to the hash table. This allows us to
+ * find this variable when lowering other (enclosing) if-statements.
+ */
+ hash_table_insert(this->condition_variables, else_var, else_var);
+ }
ir->remove();
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