109 lines
3.1 KiB
C++
109 lines
3.1 KiB
C++
/*
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* Copyright © 2010 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*/
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#include <limits.h>
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#include "main/compiler.h"
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#include "compiler/glsl_types.h"
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#include "loop_analysis.h"
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#include "ir_hierarchical_visitor.h"
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namespace {
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class loop_control_visitor : public ir_hierarchical_visitor {
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public:
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loop_control_visitor(loop_state *state)
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{
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this->state = state;
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this->progress = false;
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}
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virtual ir_visitor_status visit_leave(ir_loop *ir);
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loop_state *state;
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bool progress;
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};
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} /* anonymous namespace */
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ir_visitor_status
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loop_control_visitor::visit_leave(ir_loop *ir)
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{
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loop_variable_state *const ls = this->state->get(ir);
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/* If we've entered a loop that hasn't been analyzed, something really,
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* really bad has happened.
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*/
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if (ls == NULL) {
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assert(ls != NULL);
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return visit_continue;
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}
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if (ls->limiting_terminator != NULL) {
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/* If the limiting terminator has an iteration count of zero, then we've
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* proven that the loop cannot run, so delete it.
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*/
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int iterations = ls->limiting_terminator->iterations;
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if (iterations == 0) {
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ir->remove();
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this->progress = true;
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return visit_continue;
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}
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}
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/* Remove the conditional break statements associated with all terminators
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* that are associated with a fixed iteration count, except for the one
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* associated with the limiting terminator--that one needs to stay, since
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* it terminates the loop. Exception: if the loop still has a normative
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* bound, then that terminates the loop, so we don't even need the limiting
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* terminator.
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*/
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foreach_in_list(loop_terminator, t, &ls->terminators) {
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if (t->iterations < 0)
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continue;
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if (t != ls->limiting_terminator) {
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t->ir->remove();
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assert(ls->num_loop_jumps > 0);
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ls->num_loop_jumps--;
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this->progress = true;
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}
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}
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return visit_continue;
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}
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bool
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set_loop_controls(exec_list *instructions, loop_state *ls)
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{
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loop_control_visitor v(ls);
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v.run(instructions);
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return v.progress;
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}
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