Files
KytyPS5/src/graphics/shader/recompiler/ir/ReadLaneElimination.cpp
T

324 lines
9.4 KiB
C++

#include "graphics/shader/recompiler/ir/ReadLaneElimination.h"
#include "graphics/shader/recompiler/ir/SrtWalker.h"
#include <algorithm>
#include <iterator>
#include <map>
#include <set>
#include <utility>
namespace Libs::Graphics::ShaderRecompiler::IR {
namespace {
constexpr uint32_t FirstTemporaryScalarRegister = 128;
struct LaneKey {
uint32_t reg = 0;
uint32_t lane = 0;
auto operator<=>(const LaneKey&) const = default;
};
using LaneSet = std::set<LaneKey>;
bool PairDwordOpcode(Opcode op) {
switch (op) {
case Opcode::MoveU64:
case Opcode::WqmB64:
case Opcode::SaveexecB64:
case Opcode::BitwiseAndU64:
case Opcode::BitwiseAndNotU64:
case Opcode::BitwiseOrU64:
case Opcode::BitwiseOrNotU64:
case Opcode::BitwiseXorU64:
case Opcode::BitwiseNandU64:
case Opcode::BitwiseNorU64:
case Opcode::BitwiseXnorU64:
case Opcode::BitwiseNotU64:
case Opcode::BitFieldMaskU64:
case Opcode::BitFieldExtractU64:
case Opcode::BitReplicateB64B32:
case Opcode::ShiftLeftLogicalU64:
case Opcode::ShiftRightLogicalU64:
case Opcode::SelectU64: return true;
default: return false;
}
}
bool ResolveLane(const Program& program, const Instruction& inst, uint32_t source_index,
uint32_t& lane) {
if (source_index >= inst.src_count || (program.wave_size != 32 && program.wave_size != 64)) {
return false;
}
const auto& selector = inst.src[source_index];
if (selector.kind == OperandKind::ImmediateU32) {
lane = selector.imm % program.wave_size;
return true;
}
uint32_t folded = 0;
if (!FoldScalarConstant(program.provenance, inst.scalar_sources[source_index], folded)) {
return false;
}
lane = folded % program.wave_size;
return true;
}
bool UniformWriteSource(const Instruction& inst) {
if (inst.src_count == 0) {
return false;
}
const auto& source = inst.src[0];
if (source.kind == OperandKind::ImmediateU32 || source.kind == OperandKind::PcRelativeU32) {
return true;
}
return source.kind == OperandKind::Register &&
(source.reg.file == RegisterFile::Scalar || source.reg.file == RegisterFile::Scc ||
source.reg.file == RegisterFile::M0);
}
bool WriteLaneKey(const Program& program, const Instruction& inst, LaneKey& key) {
if (inst.op != Opcode::WriteLaneU32 || inst.dst.kind != OperandKind::Register ||
inst.dst.reg.file != RegisterFile::Vector || !UniformWriteSource(inst)) {
return false;
}
uint32_t lane = 0;
if (!ResolveLane(program, inst, 1, lane)) {
return false;
}
key = {inst.dst.reg.index, lane};
return true;
}
bool ReadLaneKey(const Program& program, const Instruction& inst, LaneKey& key) {
if (inst.op != Opcode::ReadLaneU32 || inst.src_count < 2 ||
inst.src[0].kind != OperandKind::Register || inst.src[0].reg.file != RegisterFile::Vector) {
return false;
}
uint32_t lane = 0;
if (!ResolveLane(program, inst, 1, lane)) {
return false;
}
key = {inst.src[0].reg.index, lane};
return true;
}
void InvalidateRegister(LaneSet& valid, uint32_t reg) {
const auto first = valid.lower_bound({reg, 0});
const auto last = valid.lower_bound({reg + 1u, 0});
valid.erase(first, last);
}
void ApplyInstruction(const Program& program, const Instruction& inst, LaneSet& valid) {
if (inst.op == Opcode::WriteLaneU32 && inst.dst.kind == OperandKind::Register &&
inst.dst.reg.file == RegisterFile::Vector) {
LaneKey key;
if (WriteLaneKey(program, inst, key)) {
valid.insert(key);
return;
}
uint32_t lane = 0;
if (ResolveLane(program, inst, 1, lane)) {
valid.erase({inst.dst.reg.index, lane});
} else {
InvalidateRegister(valid, inst.dst.reg.index);
}
return;
}
if (inst.op == Opcode::MoveRelDestU32 && inst.dst.kind == OperandKind::Register &&
inst.dst.reg.file == RegisterFile::Vector) {
valid.clear();
return;
}
if (inst.dst.kind == OperandKind::Register && inst.dst.reg.file == RegisterFile::Vector) {
uint32_t dwords = std::max(inst.memory.data_dwords, 1u);
if (PairDwordOpcode(inst.op) || inst.op == Opcode::UMadU64U32) {
dwords = std::max(dwords, 2u);
}
for (uint32_t i = 0; i < dwords && inst.dst.reg.index <= UINT32_MAX - i; i++) {
InvalidateRegister(valid, inst.dst.reg.index + i);
}
}
if (inst.dst2.kind == OperandKind::Register && inst.dst2.reg.file == RegisterFile::Vector) {
InvalidateRegister(valid, inst.dst2.reg.index);
}
}
LaneSet TransferBlock(const Program& program, const BasicBlock& block, LaneSet state) {
for (const auto& inst: block.instructions) {
ApplyInstruction(program, inst, state);
}
return state;
}
LaneSet Intersect(const LaneSet& left, const LaneSet& right) {
LaneSet result;
std::set_intersection(left.begin(), left.end(), right.begin(), right.end(),
std::inserter(result, result.end()));
return result;
}
uint32_t NextTemporaryScalarRegister(const Program& program) {
uint32_t next = FirstTemporaryScalarRegister;
const auto consider = [&next](const Operand& operand) {
if (operand.kind == OperandKind::Register && operand.reg.file == RegisterFile::Scalar &&
operand.reg.index >= next && operand.reg.index != UINT32_MAX) {
next = operand.reg.index + 1u;
}
};
for (const auto& block: program.blocks) {
for (const auto& inst: block.instructions) {
consider(inst.dst);
consider(inst.dst2);
for (uint32_t i = 0; i < inst.src_count; i++) {
consider(inst.src[i]);
}
}
}
return next;
}
Operand ScalarRegisterOperand(uint32_t reg) {
Operand operand;
operand.kind = OperandKind::Register;
operand.reg.file = RegisterFile::Scalar;
operand.reg.index = reg;
return operand;
}
Instruction ShadowWrite(const Instruction& write, uint32_t temporary) {
Instruction shadow;
shadow.pc = write.pc;
shadow.op = Opcode::MoveU32;
shadow.dst = ScalarRegisterOperand(temporary);
shadow.src[0] = write.src[0];
shadow.src_count = 1;
return shadow;
}
Instruction ShadowRead(const Instruction& read, uint32_t temporary) {
Instruction rewritten;
rewritten.pc = read.pc;
rewritten.op = Opcode::MoveU32;
rewritten.dst = read.dst;
rewritten.src[0] = ScalarRegisterOperand(temporary);
rewritten.src_count = 1;
return rewritten;
}
} // namespace
ReadLaneEliminationStats EliminateReadLane(Program& program) {
ReadLaneEliminationStats stats;
if (program.blocks.empty() || (program.wave_size != 32 && program.wave_size != 64)) {
return stats;
}
LaneSet universe;
for (const auto& block: program.blocks) {
for (const auto& inst: block.instructions) {
LaneKey key;
if (WriteLaneKey(program, inst, key)) {
universe.insert(key);
}
}
}
if (universe.empty()) {
return stats;
}
const size_t block_count = program.blocks.size();
std::vector<LaneSet> entry(block_count, universe);
std::vector<LaneSet> exit(block_count, universe);
entry[0].clear();
for (size_t block = 0; block < block_count; block++) {
exit[block] = TransferBlock(program, program.blocks[block], entry[block]);
}
bool changed = true;
while (changed) {
changed = false;
for (size_t block_index = 0; block_index < block_count; block_index++) {
LaneSet next_entry;
const auto& block = program.blocks[block_index];
if (block_index != 0 && !block.predecessors.empty()) {
next_entry = universe;
for (const auto predecessor: block.predecessors) {
if (predecessor >= block_count) {
next_entry.clear();
break;
}
next_entry = Intersect(next_entry, exit[predecessor]);
}
}
auto next_exit = TransferBlock(program, block, next_entry);
if (next_entry != entry[block_index] || next_exit != exit[block_index]) {
entry[block_index] = std::move(next_entry);
exit[block_index] = std::move(next_exit);
changed = true;
}
}
}
LaneSet forwarded;
for (size_t block_index = 0; block_index < block_count; block_index++) {
auto state = entry[block_index];
for (const auto& inst: program.blocks[block_index].instructions) {
LaneKey key;
if (ReadLaneKey(program, inst, key) && state.contains(key)) {
forwarded.insert(key);
}
ApplyInstruction(program, inst, state);
}
}
if (forwarded.empty()) {
return stats;
}
std::map<LaneKey, uint32_t> temporaries;
auto next_temporary = NextTemporaryScalarRegister(program);
for (const auto& key: forwarded) {
if (next_temporary == UINT32_MAX) {
return {};
}
temporaries.emplace(key, next_temporary++);
}
for (size_t block_index = 0; block_index < block_count; block_index++) {
const auto original = std::move(program.blocks[block_index].instructions);
auto& rewritten = program.blocks[block_index].instructions;
rewritten.clear();
rewritten.reserve(original.size() + temporaries.size());
auto state = entry[block_index];
for (const auto& inst: original) {
LaneKey read_key;
if (ReadLaneKey(program, inst, read_key) && state.contains(read_key)) {
const auto temporary = temporaries.find(read_key);
if (temporary != temporaries.end()) {
rewritten.push_back(ShadowRead(inst, temporary->second));
stats.rewritten_reads++;
ApplyInstruction(program, inst, state);
continue;
}
}
rewritten.push_back(inst);
LaneKey write_key;
if (WriteLaneKey(program, inst, write_key)) {
const auto temporary = temporaries.find(write_key);
if (temporary != temporaries.end()) {
rewritten.push_back(ShadowWrite(inst, temporary->second));
stats.shadow_writes++;
}
}
ApplyInstruction(program, inst, state);
}
}
return stats;
}
} // namespace Libs::Graphics::ShaderRecompiler::IR