KPGPMC/furlang
5
3
Fork 2
Code Issues 11 Pull Requests Actions Packages Projects 3 Releases Wiki Activity

feat(furc, ssa): implement phi instruction placement

Browse Source 
Refs: #2
This commit is contained in:
Aleksander Krajewski
2026-06-12 13:45:35 +02:00
parent b4fda8d7d0
commit 865691df26
2 changed files with 89 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files
furc/src/front/ssa.cpp
+68 -3
View File
@@ -1,9 +1,11 @@
#include "furc/front/ssa.hpp"
#include "furlang/ir/instruction.hpp"
#include "furlang/ir/operand.hpp"
#include <algorithm>
#include <cstddef>
#include <memory>
#include <unordered_map>
#include <unordered_set>
#include <vector>
@@ -20,19 +22,46 @@ void ssa::optimize(const std::unique_ptr<furlang::ir::function>& func) {
block_map_t predecessors;
block_map_t successors;
std::unordered_map<furlang::ir::register_operand, std::unordered_set<furlang::ir::block_index>> regSites;
std::unordered_map<furlang::ir::block_index, std::unordered_set<furlang::ir::register_operand>> regUses;
std::unordered_map<furlang::ir::block_index, furlang::ir::block_index> idoms;
for (furlang::ir::block_index i = 0; i < func->blocks().size(); ++i) {
const auto& block = func->blocks()[i];
const auto& exit = block->exit();
for (const auto& instr : block->instructions()) {
switch (instr->type()) {
case furlang::ir::instruction_t::Assign: {
const auto& assign = dynamic_cast<const furlang::ir::assign_instruction&>(*instr);
regSites[assign.destination().reg()].insert(i);
if (assign.source().type() == furlang::ir::operand_t::Register) {
regUses[i].insert(assign.source().reg());
}
} break;
case furlang::ir::instruction_t::BinaryOp: {
const auto& binOp = dynamic_cast<const furlang::ir::binary_op_instruction&>(*instr);
regSites[binOp.dst().reg()].insert(i);
if (binOp.lhs().type() == furlang::ir::operand_t::Register) {
regUses[i].insert(binOp.lhs().reg());
}
if (binOp.rhs().type() == furlang::ir::operand_t::Register) {
regUses[i].insert(binOp.rhs().reg());
}
} break;
default: break;
}
}
const auto& exit = block->exit();
switch (exit->type()) {
case furlang::ir::instruction_t::Branch: {
const auto& br = reinterpret_cast<const furlang::ir::branch_instruction&>(*exit);
const auto& br = dynamic_cast<const furlang::ir::branch_instruction&>(*exit);
predecessors[br.block()].push_back(i);
successors[i].push_back(br.block());
} break;
case furlang::ir::instruction_t::BranchCond: {
const auto& br = reinterpret_cast<const furlang::ir::branch_cond_instruction&>(*exit);
const auto& br = dynamic_cast<const furlang::ir::branch_cond_instruction&>(*exit);
predecessors[br.if_block()].push_back(i);
predecessors[br.else_block()].push_back(i);
successors[i].push_back(br.if_block());
@@ -109,6 +138,42 @@ void ssa::optimize(const std::unique_ptr<furlang::ir::function>& func) {
}
}
}
std::unordered_map<furlang::ir::block_index, std::unordered_set<furlang::ir::register_operand>> phis;
for (const auto& [reg, blocks] : regSites) {
std::vector<furlang::ir::block_index> worklist(blocks.begin(), blocks.end());
std::unordered_set<furlang::ir::block_index> added;
while (!worklist.empty()) {
auto block = worklist.back();
worklist.pop_back();
for (auto frontier : df[block]) {
if (added.find(frontier) != added.end()) continue;
phis[frontier].insert(reg);
added.insert(frontier);
if (blocks.find(frontier) == blocks.end()) {
worklist.push_back(frontier);
}
}
}
}
for (furlang::ir::block_index i = 0; i < func->blocks().size(); ++i) {
if (phis.find(i) == phis.end()) continue;
const auto& block = func->blocks()[i];
const auto& preds = predecessors[i];
for (auto reg : phis[i]) {
if (regUses[i].find(reg) == regUses[i].end()) continue;
auto phiInstr = std::make_unique<furlang::ir::phi_instruction>(reg);
for (auto pred : preds) {
phiInstr->labels().emplace_back(furlang::ir::operand::new_reg(reg), pred);
}
block->instructions().emplace(block->instructions().begin(), std::move(phiInstr));
}
}
}
void ssa::dfs_rpo(furlang::ir::block_index block,