dynarmic/src/ir_opt/dead_code_elimination_pass.cpp

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/* This file is part of the dynarmic project.
* Copyright (c) 2016 MerryMage
* This software may be used and distributed according to the terms of the GNU
* General Public License version 2 or any later version.
*/
#include "common/assert.h"
#include "frontend/ir/ir.h"
#include "ir_opt/passes.h"
namespace Dynarmic {
namespace Optimization {
void DeadCodeElimination(IR::Block& block) {
const auto is_side_effect_free = [](IR::Opcode op) -> bool {
return IR::GetTypeOf(op) != IR::Type::Void;
};
// We iterate over the instructions in reverse order.
// This is because removing an instruction reduces the number of uses for earlier instructions.
if (block.instructions.IsEmpty()) {
return;
}
auto iter = block.instructions.end();
do {
--iter;
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if (!iter->HasUses() && is_side_effect_free(iter->GetOpcode())) {
iter->Invalidate();
iter = block.instructions.erase(iter);
}
} while (iter != block.instructions.begin());
}
} // namespace Optimization
} // namespace Dynarmic