#include "loop_analysis.h"
#include "ir_hierarchical_visitor.h"
+#include "main/mtypes.h"
+
namespace {
class loop_unroll_visitor : public ir_hierarchical_visitor {
public:
- loop_unroll_visitor(loop_state *state, unsigned max_iterations)
+ loop_unroll_visitor(loop_state *state,
+ const struct gl_shader_compiler_options *options)
{
this->state = state;
this->progress = false;
- this->max_iterations = max_iterations;
+ this->options = options;
}
virtual ir_visitor_status visit_leave(ir_loop *ir);
loop_state *state;
bool progress;
- unsigned max_iterations;
+ const struct gl_shader_compiler_options *options;
};
} /* anonymous namespace */
class loop_unroll_count : public ir_hierarchical_visitor {
public:
int nodes;
- bool fail;
-
- loop_unroll_count(exec_list *list)
+ bool unsupported_variable_indexing;
+ bool array_indexed_by_induction_var_with_exact_iterations;
+ /* If there are nested loops, the node count will be inaccurate. */
+ bool nested_loop;
+
+ loop_unroll_count(exec_list *list, loop_variable_state *ls,
+ const struct gl_shader_compiler_options *options)
+ : ls(ls), options(options)
{
nodes = 0;
- fail = false;
+ nested_loop = false;
+ unsupported_variable_indexing = false;
+ array_indexed_by_induction_var_with_exact_iterations = false;
run(list);
}
- virtual ir_visitor_status visit_enter(ir_assignment *ir)
+ virtual ir_visitor_status visit_enter(ir_assignment *)
{
nodes++;
return visit_continue;
}
- virtual ir_visitor_status visit_enter(ir_expression *ir)
+ virtual ir_visitor_status visit_enter(ir_expression *)
{
nodes++;
return visit_continue;
}
- virtual ir_visitor_status visit_enter(ir_loop *ir)
+ virtual ir_visitor_status visit_enter(ir_loop *)
{
- fail = true;
+ nested_loop = true;
return visit_continue;
}
+
+ virtual ir_visitor_status visit_enter(ir_dereference_array *ir)
+ {
+ /* Force unroll in case of dynamic indexing with sampler arrays
+ * when EmitNoIndirectSampler is set.
+ */
+ if (options->EmitNoIndirectSampler) {
+ if ((ir->array->type->is_array() &&
+ ir->array->type->contains_sampler()) &&
+ !ir->array_index->constant_expression_value()) {
+ unsupported_variable_indexing = true;
+ return visit_continue;
+ }
+ }
+
+ /* Check for arrays variably-indexed by a loop induction variable.
+ * Unrolling the loop may convert that access into constant-indexing.
+ *
+ * Many drivers don't support particular kinds of variable indexing,
+ * and have to resort to using lower_variable_index_to_cond_assign to
+ * handle it. This results in huge amounts of horrible code, so we'd
+ * like to avoid that if possible. Here, we just note that it will
+ * happen.
+ */
+ if ((ir->array->type->is_array() || ir->array->type->is_matrix()) &&
+ !ir->array_index->as_constant()) {
+ ir_variable *array = ir->array->variable_referenced();
+ loop_variable *lv = ls->get(ir->array_index->variable_referenced());
+ if (array && lv && lv->is_induction_var()) {
+ /* If an array is indexed by a loop induction variable, and the
+ * array size is exactly the number of loop iterations, this is
+ * probably a simple for-loop trying to access each element in
+ * turn; the application may expect it to be unrolled.
+ */
+ if (int(array->type->length) == ls->limiting_terminator->iterations)
+ array_indexed_by_induction_var_with_exact_iterations = true;
+
+ switch (array->data.mode) {
+ case ir_var_auto:
+ case ir_var_temporary:
+ case ir_var_const_in:
+ case ir_var_function_in:
+ case ir_var_function_out:
+ case ir_var_function_inout:
+ if (options->EmitNoIndirectTemp)
+ unsupported_variable_indexing = true;
+ break;
+ case ir_var_uniform:
+ case ir_var_shader_storage:
+ if (options->EmitNoIndirectUniform)
+ unsupported_variable_indexing = true;
+ break;
+ case ir_var_shader_in:
+ if (options->EmitNoIndirectInput)
+ unsupported_variable_indexing = true;
+ break;
+ case ir_var_shader_out:
+ if (options->EmitNoIndirectOutput)
+ unsupported_variable_indexing = true;
+ break;
+ }
+ }
+ }
+ return visit_continue;
+ }
+
+private:
+ loop_variable_state *ls;
+ const struct gl_shader_compiler_options *options;
};
return visit_continue;
}
- iterations = ls->max_iterations;
-
/* Don't try to unroll loops where the number of iterations is not known
* at compile-time.
*/
- if (iterations < 0)
+ if (ls->limiting_terminator == NULL)
return visit_continue;
+ iterations = ls->limiting_terminator->iterations;
+
+ const int max_iterations = options->MaxUnrollIterations;
+
/* Don't try to unroll loops that have zillions of iterations either.
*/
- if (iterations > (int) max_iterations)
+ if (iterations > max_iterations)
return visit_continue;
/* Don't try to unroll nested loops and loops with a huge body.
*/
- loop_unroll_count count(&ir->body_instructions);
+ loop_unroll_count count(&ir->body_instructions, ls, options);
+
+ bool loop_too_large =
+ count.nested_loop || count.nodes * iterations > max_iterations * 5;
- if (count.fail || count.nodes * iterations > (int)max_iterations * 5)
+ if (loop_too_large && !count.unsupported_variable_indexing &&
+ !count.array_indexed_by_induction_var_with_exact_iterations)
return visit_continue;
- if (ls->num_loop_jumps > 1)
+ /* Note: the limiting terminator contributes 1 to ls->num_loop_jumps.
+ * We'll be removing the limiting terminator before we unroll.
+ */
+ assert(ls->num_loop_jumps > 0);
+ unsigned predicted_num_loop_jumps = ls->num_loop_jumps - 1;
+
+ if (predicted_num_loop_jumps > 1)
return visit_continue;
- if (ls->num_loop_jumps == 0) {
+ if (predicted_num_loop_jumps == 0) {
+ ls->limiting_terminator->ir->remove();
simple_unroll(ir, iterations);
return visit_continue;
}
*/
last_ir->remove();
+ ls->limiting_terminator->ir->remove();
simple_unroll(ir, 1);
return visit_continue;
}
- foreach_list(node, &ir->body_instructions) {
- /* recognize loops in the form produced by ir_lower_jumps */
- ir_instruction *cur_ir = (ir_instruction *) node;
+ /* recognize loops in the form produced by ir_lower_jumps */
+ foreach_in_list(ir_instruction, cur_ir, &ir->body_instructions) {
+ /* Skip the limiting terminator, since it will go away when we
+ * unroll.
+ */
+ if (cur_ir == ls->limiting_terminator->ir)
+ continue;
ir_if *ir_if = cur_ir->as_if();
if (ir_if != NULL) {
(ir_instruction *) ir_if->then_instructions.get_tail();
if (is_break(ir_if_last)) {
+ ls->limiting_terminator->ir->remove();
splice_post_if_instructions(ir_if, &ir_if->else_instructions);
ir_if_last->remove();
complex_unroll(ir, iterations, false);
(ir_instruction *) ir_if->else_instructions.get_tail();
if (is_break(ir_if_last)) {
+ ls->limiting_terminator->ir->remove();
splice_post_if_instructions(ir_if, &ir_if->then_instructions);
ir_if_last->remove();
complex_unroll(ir, iterations, true);
bool
-unroll_loops(exec_list *instructions, loop_state *ls, unsigned max_iterations)
+unroll_loops(exec_list *instructions, loop_state *ls,
+ const struct gl_shader_compiler_options *options)
{
- loop_unroll_visitor v(ls, max_iterations);
+ loop_unroll_visitor v(ls, options);
v.run(instructions);
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