mirror of https://gitlab.freedesktop.org/mesa/mesa
71 lines
1.5 KiB
C++
71 lines
1.5 KiB
C++
/*
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* Copyright © 2019 Valve Corporation
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*
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* SPDX-License-Identifier: MIT
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*/
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#include "aco_ir.h"
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#include <algorithm>
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#include <vector>
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/*
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* Implements an analysis pass to determine the number of uses
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* for each SSA-definition.
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*
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* This pass assumes that no loop header phis are dead code.
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*/
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namespace aco {
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namespace {
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void
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process_loop_header_phis(std::vector<uint16_t>& uses, Block& block)
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{
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for (aco_ptr<Instruction>& instr : block.instructions) {
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if (!is_phi(instr))
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return;
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for (const Operand& op : instr->operands) {
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if (op.isTemp())
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uses[op.tempId()]++;
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}
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}
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}
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void
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process_block(std::vector<uint16_t>& uses, Block& block)
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{
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for (auto it = block.instructions.rbegin(); it != block.instructions.rend(); it++) {
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aco_ptr<Instruction>& instr = *it;
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if ((block.kind & block_kind_loop_header) && is_phi(instr))
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break;
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if (!is_dead(uses, instr.get())) {
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for (const Operand& op : instr->operands) {
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if (op.isTemp())
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uses[op.tempId()]++;
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}
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}
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}
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}
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} /* end namespace */
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std::vector<uint16_t>
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dead_code_analysis(Program* program)
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{
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std::vector<uint16_t> uses(program->peekAllocationId());
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for (Block& block : program->blocks) {
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if (block.kind & block_kind_loop_header)
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process_loop_header_phis(uses, block);
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}
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for (auto it = program->blocks.rbegin(); it != program->blocks.rend(); it++)
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process_block(uses, *it);
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return uses;
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}
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} // namespace aco
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