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[midend-Loop-InductionVarStrengthReduction]支持了对部分除法运算取模运算的归纳变量的强度削弱策略。（mulh+魔数，负数2的幂次除法符号修正，2的幂次取模运算and优化）。增加了了Printer对移位指令的打印支持

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This commit is contained in:
rain2133
2025-08-13 17:41:41 +08:00
parent cd27f5fda9
commit 8b5123460b
4 changed files with 607 additions and 45 deletions
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103
src/midend/Pass/Analysis/LoopCharacteristics.cpp
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@@ -321,7 +321,7 @@ void LoopCharacteristicsPass::identifyBasicInductionVariables(
auto* phi = dynamic_cast<PhiInst*>(inst.get());
if (!phi) continue;
if (isBasicInductionVariable(phi, loop)) {
ivs.push_back(InductionVarInfo::createBasicBIV(phi, Instruction::Kind::kPhi));
ivs.push_back(InductionVarInfo::createBasicBIV(phi, Instruction::Kind::kPhi, phi));
if (DEBUG) {
std::cout << " [BIV] Found basic induction variable: " << phi->getName() << std::endl;
std::cout << " Incoming values: ";
@@ -340,9 +340,23 @@ void LoopCharacteristicsPass::identifyBasicInductionVariables(
// 2. 递归识别所有派生DIV
std::set<Value*> visited;
size_t initialSize = ivs.size();
for (const auto& biv : ivs) {
// 保存初始的BIV列表，避免在遍历过程中修改向量导致迭代器失效
std::vector<InductionVarInfo*> bivList;
for (size_t i = 0; i < initialSize; ++i) {
if (ivs[i] && ivs[i]->ivkind == IVKind::kBasic) {
bivList.push_back(ivs[i].get());
}
}
for (auto* biv : bivList) {
if (DEBUG) {
std::cout << " Searching for derived IVs from BIV: " << biv->div->getName() << std::endl;
if (biv && biv->div) {
std::cout << " Searching for derived IVs from BIV: " << biv->div->getName() << std::endl;
} else {
std::cout << " ERROR: Invalid BIV pointer or div field is null" << std::endl;
continue;
}
}
findDerivedInductionVars(biv->div, biv->base, loop, ivs, visited);
}
@@ -537,6 +551,58 @@ static LinearExpr analyzeLinearExpr(Value* val, Loop* loop, std::vector<std::uni
std::cout << " -> Multiplication pattern not supported" << std::endl;
}
}
// 除法：BIV/const（仅当const是2的幂时）
if (kind == Instruction::Kind::kDiv) {
if (DEBUG >= 2) {
std::cout << " -> Analyzing division" << std::endl;
}
auto expr0 = analyzeLinearExpr(inst->getOperand(0), loop, ivs);
auto expr1 = analyzeLinearExpr(inst->getOperand(1), loop, ivs);
// 只支持 BIV / 2^n 形式
if (expr0.base1 && !expr1.base1 && !expr1.base2 && expr1.offset > 0) {
// 检查是否为2的幂
int divisor = expr1.offset;
if ((divisor & (divisor - 1)) == 0) { // 2的幂检查
if (DEBUG >= 2) {
std::cout << " -> BIV / power_of_2 pattern (divisor=" << divisor << ")" << std::endl;
}
// 对于除法，我们记录为特殊的归纳变量模式
// factor表示除数（用于后续强度削弱）
return {expr0.base1, nullptr, -divisor, 0, expr0.offset / divisor, true, true};
}
}
if (DEBUG >= 2) {
std::cout << " -> Division pattern not supported (not power of 2)" << std::endl;
}
}
// 取模：BIV % const（仅当const是2的幂时）
if (kind == Instruction::Kind::kRem) {
if (DEBUG >= 2) {
std::cout << " -> Analyzing remainder" << std::endl;
}
auto expr0 = analyzeLinearExpr(inst->getOperand(0), loop, ivs);
auto expr1 = analyzeLinearExpr(inst->getOperand(1), loop, ivs);
// 只支持 BIV % 2^n 形式
if (expr0.base1 && !expr1.base1 && !expr1.base2 && expr1.offset > 0) {
// 检查是否为2的幂
int modulus = expr1.offset;
if ((modulus & (modulus - 1)) == 0) { // 2的幂检查
if (DEBUG >= 2) {
std::cout << " -> BIV % power_of_2 pattern (modulus=" << modulus << ")" << std::endl;
}
// 对于取模，我们记录为特殊的归纳变量模式
// 使用负的模数来区分取模和除法
return {expr0.base1, nullptr, -10000 - modulus, 0, 0, true, true}; // 特殊标记
}
}
if (DEBUG >= 2) {
std::cout << " -> Remainder pattern not supported (not power of 2)" << std::endl;
}
}
}
// 其它情况
@@ -648,7 +714,7 @@ void LoopCharacteristicsPass::findDerivedInductionVars(
<< " (kind: " << static_cast<int>(inst->getKind()) << ")" << std::endl;
}
// 下面是一个例子：假设你有线性归约分析（可用analyzeLinearExpr等递归辅助）
// 线性归约分析
auto expr = analyzeLinearExpr(inst, loop, ivs);
if (!expr.valid) {
@@ -669,14 +735,29 @@ void LoopCharacteristicsPass::findDerivedInductionVars(
// 单BIV线性
if (expr.base1 && !expr.base2) {
if (DEBUG) {
std::cout << " [DIV-LINEAR] Creating single-base derived IV: " << inst->getName()
<< " with base: " << expr.base1->getName()
<< ", factor: " << expr.factor1
<< ", offset: " << expr.offset << std::endl;
// 检查这个指令是否已经是一个已知的IV（特别是BIV），避免重复创建
bool alreadyExists = false;
for (const auto& existingIV : ivs) {
if (existingIV->div == inst) {
alreadyExists = true;
if (DEBUG) {
std::cout << " [DIV-SKIP] Instruction " << inst->getName()
<< " already exists as IV, skipping creation" << std::endl;
}
break;
}
}
if (!alreadyExists) {
if (DEBUG) {
std::cout << " [DIV-LINEAR] Creating single-base derived IV: " << inst->getName()
<< " with base: " << expr.base1->getName()
<< ", factor: " << expr.factor1
<< ", offset: " << expr.offset << std::endl;
}
ivs.push_back(InductionVarInfo::createSingleDIV(inst, inst->getKind(), expr.base1, expr.factor1, expr.offset));
findDerivedInductionVars(inst, expr.base1, loop, ivs, visited);
}
ivs.push_back(InductionVarInfo::createSingleDIV(inst, inst->getKind(), expr.base1, expr.factor1, expr.offset));
findDerivedInductionVars(inst, expr.base1, loop, ivs, visited);
}
// 双BIV线性
else if (expr.base1 && expr.base2) {