suyu/src/shader_recompiler/frontend/ir/post_order.cpp

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2021-02-15 00:15:42 +01:00
// Copyright 2021 yuzu Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <boost/container/flat_set.hpp>
#include <boost/container/small_vector.hpp>
#include "shader_recompiler/frontend/ir/basic_block.h"
#include "shader_recompiler/frontend/ir/post_order.h"
namespace Shader::IR {
BlockList PostOrder(const BlockList& blocks) {
boost::container::small_vector<Block*, 16> block_stack;
boost::container::flat_set<Block*> visited;
BlockList post_order_blocks;
post_order_blocks.reserve(blocks.size());
Block* const first_block{blocks.front()};
visited.insert(first_block);
block_stack.push_back(first_block);
const auto visit_branch = [&](Block* block, Block* branch) {
if (!branch) {
return false;
}
if (!visited.insert(branch).second) {
return false;
}
// Calling push_back twice is faster than insert on msvc
block_stack.push_back(block);
block_stack.push_back(branch);
return true;
};
while (!block_stack.empty()) {
Block* const block{block_stack.back()};
block_stack.pop_back();
if (!visit_branch(block, block->TrueBranch()) &&
!visit_branch(block, block->FalseBranch())) {
post_order_blocks.push_back(block);
}
}
return post_order_blocks;
}
} // namespace Shader::IR