+++ /dev/null
-/*
- * Copyright © 2010 Intel Corporation
- *
- * Permission is hereby granted, free of charge, to any person obtaining a
- * copy of this software and associated documentation files (the "Software"),
- * to deal in the Software without restriction, including without limitation
- * the rights to use, copy, modify, merge, publish, distribute, sublicense,
- * and/or sell copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice (including the next
- * paragraph) shall be included in all copies or substantial portions of the
- * Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
- * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- */
-
-/**
- * \file opt_copy_propagation.cpp
- *
- * Moves usage of recently-copied variables to the previous copy of
- * the variable.
- *
- * This should reduce the number of MOV instructions in the generated
- * programs unless copy propagation is also done on the LIR, and may
- * help anyway by triggering other optimizations that live in the HIR.
- */
-
-#include "ir.h"
-#include "ir_visitor.h"
-#include "ir_basic_block.h"
-#include "ir_optimization.h"
-#include "compiler/glsl_types.h"
-
-namespace {
-
-class acp_entry : public exec_node
-{
-public:
- acp_entry(ir_variable *lhs, ir_variable *rhs)
- {
- assert(lhs);
- assert(rhs);
- this->lhs = lhs;
- this->rhs = rhs;
- }
-
- ir_variable *lhs;
- ir_variable *rhs;
-};
-
-
-class kill_entry : public exec_node
-{
-public:
- kill_entry(ir_variable *var)
- {
- assert(var);
- this->var = var;
- }
-
- ir_variable *var;
-};
-
-class ir_copy_propagation_visitor : public ir_hierarchical_visitor {
-public:
- ir_copy_propagation_visitor()
- {
- progress = false;
- mem_ctx = ralloc_context(0);
- this->acp = new(mem_ctx) exec_list;
- this->kills = new(mem_ctx) exec_list;
- }
- ~ir_copy_propagation_visitor()
- {
- ralloc_free(mem_ctx);
- }
-
- virtual ir_visitor_status visit(class ir_dereference_variable *);
- virtual ir_visitor_status visit_enter(class ir_loop *);
- virtual ir_visitor_status visit_enter(class ir_function_signature *);
- virtual ir_visitor_status visit_enter(class ir_function *);
- virtual ir_visitor_status visit_leave(class ir_assignment *);
- virtual ir_visitor_status visit_enter(class ir_call *);
- virtual ir_visitor_status visit_enter(class ir_if *);
-
- void add_copy(ir_assignment *ir);
- void kill(ir_variable *ir);
- void handle_if_block(exec_list *instructions);
-
- /** List of acp_entry: The available copies to propagate */
- exec_list *acp;
- /**
- * List of kill_entry: The variables whose values were killed in this
- * block.
- */
- exec_list *kills;
-
- bool progress;
-
- bool killed_all;
-
- void *mem_ctx;
-};
-
-} /* unnamed namespace */
-
-ir_visitor_status
-ir_copy_propagation_visitor::visit_enter(ir_function_signature *ir)
-{
- /* Treat entry into a function signature as a completely separate
- * block. Any instructions at global scope will be shuffled into
- * main() at link time, so they're irrelevant to us.
- */
- exec_list *orig_acp = this->acp;
- exec_list *orig_kills = this->kills;
- bool orig_killed_all = this->killed_all;
-
- this->acp = new(mem_ctx) exec_list;
- this->kills = new(mem_ctx) exec_list;
- this->killed_all = false;
-
- visit_list_elements(this, &ir->body);
-
- ralloc_free(this->acp);
- ralloc_free(this->kills);
-
- this->kills = orig_kills;
- this->acp = orig_acp;
- this->killed_all = orig_killed_all;
-
- return visit_continue_with_parent;
-}
-
-ir_visitor_status
-ir_copy_propagation_visitor::visit_leave(ir_assignment *ir)
-{
- kill(ir->lhs->variable_referenced());
-
- add_copy(ir);
-
- return visit_continue;
-}
-
-ir_visitor_status
-ir_copy_propagation_visitor::visit_enter(ir_function *ir)
-{
- (void) ir;
- return visit_continue;
-}
-
-/**
- * Replaces dereferences of ACP RHS variables with ACP LHS variables.
- *
- * This is where the actual copy propagation occurs. Note that the
- * rewriting of ir_dereference means that the ir_dereference instance
- * must not be shared by multiple IR operations!
- */
-ir_visitor_status
-ir_copy_propagation_visitor::visit(ir_dereference_variable *ir)
-{
- if (this->in_assignee)
- return visit_continue;
-
- ir_variable *var = ir->var;
-
- foreach_in_list(acp_entry, entry, this->acp) {
- if (var == entry->lhs) {
- ir->var = entry->rhs;
- this->progress = true;
- break;
- }
- }
-
- return visit_continue;
-}
-
-
-ir_visitor_status
-ir_copy_propagation_visitor::visit_enter(ir_call *ir)
-{
- /* Do copy propagation on call parameters, but skip any out params */
- foreach_two_lists(formal_node, &ir->callee->parameters,
- actual_node, &ir->actual_parameters) {
- ir_variable *sig_param = (ir_variable *) formal_node;
- ir_rvalue *ir = (ir_rvalue *) actual_node;
- if (sig_param->data.mode != ir_var_function_out
- && sig_param->data.mode != ir_var_function_inout) {
- ir->accept(this);
- }
- }
-
- /* Since we're unlinked, we don't (necessarily) know the side effects of
- * this call. So kill all copies.
- */
- acp->make_empty();
- this->killed_all = true;
-
- return visit_continue_with_parent;
-}
-
-void
-ir_copy_propagation_visitor::handle_if_block(exec_list *instructions)
-{
- exec_list *orig_acp = this->acp;
- exec_list *orig_kills = this->kills;
- bool orig_killed_all = this->killed_all;
-
- this->acp = new(mem_ctx) exec_list;
- this->kills = new(mem_ctx) exec_list;
- this->killed_all = false;
-
- /* Populate the initial acp with a copy of the original */
- foreach_in_list(acp_entry, a, orig_acp) {
- this->acp->push_tail(new(this->acp) acp_entry(a->lhs, a->rhs));
- }
-
- visit_list_elements(this, instructions);
-
- if (this->killed_all) {
- orig_acp->make_empty();
- }
-
- exec_list *new_kills = this->kills;
- this->kills = orig_kills;
- ralloc_free(this->acp);
- this->acp = orig_acp;
- this->killed_all = this->killed_all || orig_killed_all;
-
- foreach_in_list(kill_entry, k, new_kills) {
- kill(k->var);
- }
-
- ralloc_free(new_kills);
-}
-
-ir_visitor_status
-ir_copy_propagation_visitor::visit_enter(ir_if *ir)
-{
- ir->condition->accept(this);
-
- handle_if_block(&ir->then_instructions);
- handle_if_block(&ir->else_instructions);
-
- /* handle_if_block() already descended into the children. */
- return visit_continue_with_parent;
-}
-
-ir_visitor_status
-ir_copy_propagation_visitor::visit_enter(ir_loop *ir)
-{
- exec_list *orig_acp = this->acp;
- exec_list *orig_kills = this->kills;
- bool orig_killed_all = this->killed_all;
-
- /* FINISHME: For now, the initial acp for loops is totally empty.
- * We could go through once, then go through again with the acp
- * cloned minus the killed entries after the first run through.
- */
- this->acp = new(mem_ctx) exec_list;
- this->kills = new(mem_ctx) exec_list;
- this->killed_all = false;
-
- visit_list_elements(this, &ir->body_instructions);
-
- if (this->killed_all) {
- orig_acp->make_empty();
- }
-
- exec_list *new_kills = this->kills;
- this->kills = orig_kills;
- ralloc_free(this->acp);
- this->acp = orig_acp;
- this->killed_all = this->killed_all || orig_killed_all;
-
- foreach_in_list(kill_entry, k, new_kills) {
- kill(k->var);
- }
-
- ralloc_free(new_kills);
-
- /* already descended into the children. */
- return visit_continue_with_parent;
-}
-
-void
-ir_copy_propagation_visitor::kill(ir_variable *var)
-{
- assert(var != NULL);
-
- /* Remove any entries currently in the ACP for this kill. */
- foreach_in_list_safe(acp_entry, entry, acp) {
- if (entry->lhs == var || entry->rhs == var) {
- entry->remove();
- }
- }
-
- /* Add the LHS variable to the list of killed variables in this block.
- */
- this->kills->push_tail(new(this->kills) kill_entry(var));
-}
-
-/**
- * Adds an entry to the available copy list if it's a plain assignment
- * of a variable to a variable.
- */
-void
-ir_copy_propagation_visitor::add_copy(ir_assignment *ir)
-{
- acp_entry *entry;
-
- if (ir->condition)
- return;
-
- ir_variable *lhs_var = ir->whole_variable_written();
- ir_variable *rhs_var = ir->rhs->whole_variable_referenced();
-
- if ((lhs_var != NULL) && (rhs_var != NULL)) {
- if (lhs_var == rhs_var) {
- /* This is a dumb assignment, but we've conveniently noticed
- * it here. Removing it now would mess up the loop iteration
- * calling us. Just flag it to not execute, and someone else
- * will clean up the mess.
- */
- ir->condition = new(ralloc_parent(ir)) ir_constant(false);
- this->progress = true;
- } else if (lhs_var->data.mode != ir_var_shader_storage &&
- lhs_var->data.mode != ir_var_shader_shared) {
- entry = new(this->acp) acp_entry(lhs_var, rhs_var);
- this->acp->push_tail(entry);
- }
- }
-}
-
-/**
- * Does a copy propagation pass on the code present in the instruction stream.
- */
-bool
-do_copy_propagation(exec_list *instructions)
-{
- ir_copy_propagation_visitor v;
-
- visit_list_elements(&v, instructions);
-
- return v.progress;
-}
projects / mesa.git / blobdiff