[Lab4.2] Publish

Documentations/common/simple_cpp.md

@@ -106,3 +106,13 @@ C中，只能使用标准库中的`malloc`与`free`来进行内存分配，并
 1. `std::shared_ptr`: 引用计数智能指针，使用一个共享变量来记录指针管理的对象被引用了几次。当对象引用计数为0时，说明当前该对象不再有引用，并且进程也无法再通过其它方式来引用它，也就意味着可以回收内存，这相当于低级的垃圾回收策略。
 2. `std::unique_ptr`: 表示所有权的智能指针，该指针要求它所管理的对象智能有一次引用，主要用于语义上不允许共享的对象（比如`llvm::Module`）。当引用计数为0时，它也会回收内存。
 
+## Debugging Seg Fault
+Lab3/4 中，你可能会各种各样的段错误，不要害怕！clang 提供了一个工具来帮助我们解决内存泄漏。
+```bash
+cd build
+cmake .. -DCMAKE_BUILD_TYPE=Asan
+make
+```
+然后再次运行你的错误代码， Asan 会提供更详细的报错信息。
+
+注：要更换到别的 build type （如Debug或Release）时需要显式指定，否则 cmake 会使用 cached 的版本。

Reports/4.2-gvn/report.md

+# Lab4.2 实验报告
+
+姓名 学号
+
+## 实验要求
+
+请按照自己的理解，写明本次实验需要做什么
+
+## 实验难点
+
+实验中遇到哪些挑战
+
+## 实验设计
+实现思路，相应代码，优化前后的IR对比（举一个例子）并辅以简单说明
+
+### 思考题
+1. 请简要分析你的算法复杂度
+2. `std::shared_ptr`如果存在环形引用，则无法正确释放内存，你的 Expression 类是否存在 circular reference?
+3. 尽管本次实验已经写了很多代码，但是在算法上和工程上仍然可以对 GVN 进行改进，请简述你的 GVN 实现可以改进的地方
+
+## 实验总结
+
+此次实验有什么收获
+
+## 实验反馈（可选 不会评分）
+
+对本次实验的建议
+

include/lightir/Instruction.h

@@ -55,8 +55,8 @@ class Instruction : public User, public llvm::ilist_node<Instruction> {
     Module *get_module();
 
     OpID get_instr_type() const { return op_id_; }
-    std::string get_instr_op_name() {
-        switch (op_id_) {
+    static std::string get_instr_op_name(OpID id) {
+        switch (id) {
         case ret: return "ret"; break;
         case br: return "br"; break;
         case add: return "add"; break;
@@ -82,6 +82,7 @@ class Instruction : public User, public llvm::ilist_node<Instruction> {
         default: return ""; break;
         }
     }
+    std::string get_instr_op_name() { return get_instr_op_name(op_id_); }
 
     bool is_void() {
         return ((op_id_ == ret) || (op_id_ == br) || (op_id_ == store) ||

include/lightir/Value.h

 #ifndef SYSYC_VALUE_H
 #define SYSYC_VALUE_H
 
+#include <functional>
 #include <iostream>
 #include <list>
 #include <string>
 
 class Type;
 class Value;
+class User;
 
 struct Use {
     Value *val_;
@@ -35,6 +37,8 @@ class Value {
     std::string get_name() const;
 
     void replace_all_use_with(Value *new_val);
+    /// replace `value` with `new_val` when the user of value satisfies predicate `pred`
+    void replace_use_with_when(Value *new_val, std::function<bool(User *)> pred);
     void remove_use(Value *val);
 
     virtual std::string print() = 0;

include/optimization/DeadCode.h

+#pragma once
+#include "FuncInfo.h"
+#include "Function.h"
+#include "Instruction.h"
+#include "PassManager.hpp"
+#include "logging.hpp"
+
+/**
+ * 死代码消除：参见 https://www.clear.rice.edu/comp512/Lectures/10Dead-Clean-SCCP.pdf
+ **/
+class DeadCode : public Pass {
+  public:
+    DeadCode(Module *m) : Pass(m), func_info(std::make_shared<FuncInfo>(m)) {}
+
+    // 处理流程：两趟处理，mark 标记有用变量，sweep 删除无用指令
+    void run() {
+        bool changed{};
+        func_info->run();
+        do {
+            changed = false;
+            for (auto &F : m_->get_functions()) {
+                auto func = &F;
+                mark(func);
+                changed |= sweep(func);
+            }
+        } while (changed);
+        LOG_INFO << "dead code pass erased " << ins_count << " instructions";
+    }
+
+  private:
+    std::shared_ptr<FuncInfo> func_info;
+    void mark(Function *func) {
+        work_list.clear();
+        marked.clear();
+
+        for (auto &bb : func->get_basic_blocks()) {
+            for (auto &ins : bb.get_instructions()) {
+                if (is_critical(&ins)) {
+                    marked[&ins] = true;
+                    work_list.push_back(&ins);
+                }
+            }
+        }
+
+        while (work_list.empty() == false) {
+            auto now = work_list.front();
+            work_list.pop_front();
+
+            mark(now);
+        }
+    }
+    void mark(Instruction *ins) {
+        for (auto op : ins->get_operands()) {
+            auto def = dynamic_cast<Instruction *>(op);
+            if (def == nullptr)
+                continue;
+            if (marked[def])
+                continue;
+            if (def->get_function() != ins->get_function())
+                continue;
+            marked[def] = true;
+            work_list.push_back(def);
+        }
+    }
+    bool sweep(Function *func) {
+        std::unordered_set<Instruction *> wait_del{};
+        for (auto &bb : func->get_basic_blocks()) {
+            for (auto it = bb.get_instructions().begin(); it != bb.get_instructions().end();) {
+                if (marked[&*it]) {
+                    ++it;
+                    continue;
+                } else {
+                    auto tmp = &*it;
+                    wait_del.insert(tmp);
+                    it++;
+                }
+            }
+        }
+        for (auto inst : wait_del)
+            inst->remove_use_of_ops();
+        for (auto inst : wait_del)
+            inst->get_parent()->get_instructions().erase(inst);
+        ins_count += wait_del.size();
+        return not wait_del.empty(); // changed
+    }
+    bool is_critical(Instruction *ins) {
+        // 对纯函数的无用调用也可以在删除之列
+        if (ins->is_call()) {
+            auto call_inst = dynamic_cast<CallInst *>(ins);
+            auto callee = dynamic_cast<Function *>(call_inst->get_operand(0));
+            if (func_info->is_pure_function(callee))
+                return false;
+            return true;
+        }
+        if (ins->is_br() || ins->is_ret())
+            return true;
+        if (ins->is_store())
+            return true;
+        return false;
+    }
+
+    // 用以衡量死代码消除的性能
+    int ins_count{0};
+    std::deque<Instruction *> work_list{};
+    std::unordered_map<Instruction *, bool> marked{};
+};

include/optimization/FuncInfo.h

+#pragma once
+#include "Function.h"
+#include "PassManager.hpp"
+#include "logging.hpp"
+
+#include <deque>
+#include <unordered_map>
+#include <unordered_set>
+
+/**
+ * 计算哪些函数是纯函数
+ * WARN: 假定所有函数都是纯函数，除非他写入了全局变量、修改了传入的数组、或者直接间接调用了非纯函数
+ */
+class FuncInfo : public Pass {
+  public:
+    FuncInfo(Module *m) : Pass(m) {}
+
+    void run() {
+        for (auto &f : m_->get_functions()) {
+            auto func = &f;
+            trivial_mark(func);
+            if (not is_pure[func])
+                worklist.push_back(func);
+        }
+        while (worklist.empty() == false) {
+            auto now = worklist.front();
+            worklist.pop_front();
+            process(now);
+        }
+        log();
+    }
+
+    bool is_pure_function(Function *func) const {
+        // exit_if(is_pure.find(func) == is_pure.end(), ERROR_IN_PURE_FUNCTION_ANALYSIS);
+        return is_pure.at(func);
+    }
+
+    void log() {
+        for (auto it : is_pure) {
+            LOG_INFO << it.first->get_name() << " is pure? " << it.second;
+        }
+    }
+
+  private:
+    // 有 store 操作的函数非纯函数来处理
+    void trivial_mark(Function *func) {
+        if (func->is_declaration() or func->get_name() == "main") {
+            is_pure[func] = false;
+            return;
+        }
+        // 只要传入数组，都作为非纯函数处理
+        for (auto it = func->get_function_type()->param_begin(); it != func->get_function_type()->param_end(); ++it) {
+            auto arg_type = *it;
+            if (arg_type->is_integer_type() == false and arg_type->is_float_type() == false) {
+                is_pure[func] = false;
+                return;
+            }
+        }
+        for (auto &bb : func->get_basic_blocks())
+            for (auto &inst : bb.get_instructions()) {
+                if (is_side_effect_inst(&inst)) {
+                    is_pure[func] = false;
+                    return;
+                }
+            }
+        is_pure[func] = true;
+    }
+
+    void process(Function *func) {
+        for (auto &use : func->get_use_list()) {
+            LOG_INFO << use.val_->print() << " uses func: " << func->get_name();
+            if (auto inst = dynamic_cast<Instruction *>(use.val_)) {
+                auto func = (inst->get_parent()->get_parent());
+                if (is_pure[func]) {
+                    is_pure[func] = false;
+                    worklist.push_back(func);
+                }
+            } else
+                LOG_WARNING << "Value besides instruction uses a function";
+        }
+    }
+
+    // 对局部变量进行 store 没有副作用
+    bool is_side_effect_inst(Instruction *inst) {
+        if (inst->is_store()) {
+            if (is_local_store(dynamic_cast<StoreInst *>(inst)))
+                return false;
+            return true;
+        }
+        if (inst->is_load()) {
+            if (is_local_load(dynamic_cast<LoadInst *>(inst)))
+                return false;
+            return true;
+        }
+        // call 指令的副作用会在后续 bfs 中计算
+        return false;
+    }
+
+    bool is_local_load(LoadInst *inst) {
+        auto addr = dynamic_cast<Instruction *>(get_first_addr(inst->get_operand(0)));
+        if (addr and addr->is_alloca())
+            return true;
+        return false;
+    }
+
+    bool is_local_store(StoreInst *inst) {
+        auto addr = dynamic_cast<Instruction *>(get_first_addr(inst->get_lval()));
+        if (addr and addr->is_alloca())
+            return true;
+        return false;
+    }
+    Value *get_first_addr(Value *val) {
+        if (auto inst = dynamic_cast<Instruction *>(val)) {
+            if (inst->is_alloca())
+                return inst;
+            if (inst->is_gep())
+                return get_first_addr(inst->get_operand(0));
+            if (inst->is_load())
+                return val;
+            LOG_WARNING << "FuncInfo: try to determine addr in operands";
+            for (auto op : inst->get_operands()) {
+                if (op->get_type()->is_pointer_type())
+                    return get_first_addr(op);
+            }
+        }
+        return val;
+    }
+
+    std::deque<Function *> worklist;
+    std::unordered_map<Function *, bool> is_pure;
+};

include/optimization/GVN.h

+#pragma once
+#include "BasicBlock.h"
+#include "Constant.h"
+#include "DeadCode.h"
+#include "FuncInfo.h"
+#include "Function.h"
+#include "Instruction.h"
+#include "Module.h"
+#include "PassManager.hpp"
+#include "Value.h"
+
+#include <cstddef>
+#include <cstdint>
+#include <memory>
+#include <optional>
+#include <string>
+#include <tuple>
+#include <unordered_map>
+#include <utility>
+#include <vector>
+
+namespace GVNExpression {
+
+// fold the constant value
+class ConstFolder {
+  public:
+    ConstFolder(Module *m) : module_(m) {}
+    Constant *compute(Instruction *instr, Constant *value1, Constant *value2);
+    Constant *compute(Instruction *instr, Constant *value1);
+
+  private:
+    Module *module_;
+};
+
+/**
+ * for constructor of class derived from `Expression`, we make it public
+ * because `std::make_shared` needs the constructor to be publicly available,
+ * but you should call the static factory method `create` instead the constructor itself to get the desired data
+ */
+class Expression {
+  public:
+    // TODO: you need to extend expression types according to testcases
+    enum gvn_expr_t { e_constant, e_bin, e_phi };
+    Expression(gvn_expr_t t) : expr_type(t) {}
+    virtual ~Expression() = default;
+    virtual std::string print() = 0;
+    gvn_expr_t get_expr_type() const { return expr_type; }
+
+  private:
+    gvn_expr_t expr_type;
+};
+
+bool operator==(const std::shared_ptr<Expression> &lhs, const std::shared_ptr<Expression> &rhs);
+bool operator==(const GVNExpression::Expression &lhs, const GVNExpression::Expression &rhs);
+
+class ConstantExpression : public Expression {
+  public:
+    static std::shared_ptr<ConstantExpression> create(Constant *c) { return std::make_shared<ConstantExpression>(c); }
+    virtual std::string print() { return c_->print(); }
+    // we leverage the fact that constants in lightIR have unique addresses
+    bool equiv(const ConstantExpression *other) const { return c_ == other->c_; }
+    ConstantExpression(Constant *c) : Expression(e_constant), c_(c) {}
+
+  private:
+    Constant *c_;
+};
+
+// arithmetic expression
+class BinaryExpression : public Expression {
+  public:
+    static std::shared_ptr<BinaryExpression> create(Instruction::OpID op,
+                                                    std::shared_ptr<Expression> lhs,
+                                                    std::shared_ptr<Expression> rhs) {
+        return std::make_shared<BinaryExpression>(op, lhs, rhs);
+    }
+    virtual std::string print() {
+        return "(" + Instruction::get_instr_op_name(op_) + " " + lhs_->print() + " " + rhs_->print() + ")";
+    }
+
+    bool equiv(const BinaryExpression *other) const {
+        if (op_ == other->op_ and *lhs_ == *other->lhs_ and *rhs_ == *other->rhs_)
+            return true;
+        else
+            return false;
+    }
+
+    BinaryExpression(Instruction::OpID op, std::shared_ptr<Expression> lhs, std::shared_ptr<Expression> rhs)
+        : Expression(e_bin), op_(op), lhs_(lhs), rhs_(rhs) {}
+
+  private:
+    Instruction::OpID op_;
+    std::shared_ptr<Expression> lhs_, rhs_;
+};
+
+class PhiExpression : public Expression {
+  public:
+    static std::shared_ptr<PhiExpression> create(std::shared_ptr<Expression> lhs, std::shared_ptr<Expression> rhs) {
+        return std::make_shared<PhiExpression>(lhs, rhs);
+    }
+    virtual std::string print() { return "(phi " + lhs_->print() + " " + rhs_->print() + ")"; }
+    bool equiv(const PhiExpression *other) const {
+        if (*lhs_ == *other->lhs_ and *rhs_ == *other->rhs_)
+            return true;
+        else
+            return false;
+    }
+    PhiExpression(std::shared_ptr<Expression> lhs, std::shared_ptr<Expression> rhs)
+        : Expression(e_phi), lhs_(lhs), rhs_(rhs) {}
+
+  private:
+    std::shared_ptr<Expression> lhs_, rhs_;
+};
+} // namespace GVNExpression
+
+/**
+ * Congruence class in each partitions
+ * note: for constant propagation, you might need to add other fields
+ * and for load/store redundancy detection, you most certainly need to modify the class
+ */
+struct CongruenceClass {
+    size_t index_;
+    // representative of the congruence class, used to replace all the members (except itself) when analysis is done
+    Value *leader_;
+    // value expression in congruence class
+    std::shared_ptr<GVNExpression::Expression> value_expr_;
+    // value φ-function is an annotation of the congruence class
+    std::shared_ptr<GVNExpression::PhiExpression> value_phi_;
+    // equivalent variables in one congruence class
+    std::set<Value *> members_;
+
+    CongruenceClass(size_t index) : index_(index), leader_{}, value_expr_{}, value_phi_{}, members_{} {}
+
+    bool operator<(const CongruenceClass &other) const { return this->index_ < other.index_; }
+    bool operator==(const CongruenceClass &other) const;
+};
+
+namespace std {
+template <>
+// overload std::less for std::shared_ptr<CongruenceClass>, i.e. how to sort the congruence classes
+struct less<std::shared_ptr<CongruenceClass>> {
+    bool operator()(const std::shared_ptr<CongruenceClass> &a, const std::shared_ptr<CongruenceClass> &b) const {
+        // nullptrs should never appear in partitions, so we just dereference it
+        return *a < *b;
+    }
+};
+} // namespace std
+
+class GVN : public Pass {
+  public:
+    using partitions = std::set<std::shared_ptr<CongruenceClass>>;
+    GVN(Module *m, bool dump_json) : Pass(m), dump_json_(dump_json) {}
+    // pass start
+    void run() override;
+    // init for pass metadata;
+    void initPerFunction();
+
+    // fill the following functions according to Pseudocode, **you might need to add more arguments**
+    void detectEquivalences();
+    partitions join(const partitions &P1, const partitions &P2);
+    std::shared_ptr<CongruenceClass> intersect(std::shared_ptr<CongruenceClass>, std::shared_ptr<CongruenceClass>);
+    partitions transferFunction(Instruction *x, Value *e, partitions pin);
+    std::shared_ptr<GVNExpression::PhiExpression> valuePhiFunc(std::shared_ptr<GVNExpression::Expression>,
+                                                               const partitions &);
+    std::shared_ptr<GVNExpression::Expression> valueExpr(Instruction *instr);
+    std::shared_ptr<GVNExpression::Expression> getVN(const partitions &pout,
+                                                     std::shared_ptr<GVNExpression::Expression> ve);
+
+    // replace cc members with leader
+    void replace_cc_members();
+
+    // note: be careful when to use copy constructor or clone
+    partitions clone(const partitions &p);
+
+    // create congruence class helper
+    std::shared_ptr<CongruenceClass> createCongruenceClass(size_t index = 0) {
+        return std::make_shared<CongruenceClass>(index);
+    }
+
+  private:
+    bool dump_json_;
+    std::uint64_t next_value_number_ = 1;
+    Function *func_;
+    std::map<BasicBlock *, partitions> pin_, pout_;
+    std::unique_ptr<FuncInfo> func_info_;
+    std::unique_ptr<GVNExpression::ConstFolder> folder_;
+    std::unique_ptr<DeadCode> dce_;
+};
+
+bool operator==(const GVN::partitions &p1, const GVN::partitions &p2);

src/CMakeLists.txt

@@ -3,4 +3,4 @@ add_subdirectory(common)
 add_subdirectory(io)
 add_subdirectory(lightir)
 add_subdirectory(cminusfc)
-add_subdirectory(optimization)
+add_subdirectory(optimization)
\ No newline at end of file

src/cminusfc/cminusfc.cpp

 #include "Dominators.h"
+#include "GVN.h"
 #include "Mem2Reg.hpp"
 #include "PassManager.hpp"
 #include "cminusf_builder.hpp"
@@ -11,7 +12,8 @@
 using namespace std::literals::string_literals;
 
 void print_help(std::string exe_name) {
-    std::cout << "Usage: " << exe_name << " [ -h | --help ] [ -o <target-file> ] [ -emit-llvm ] [-mem2reg] <input-file>"
+    std::cout << "Usage: " << exe_name
+              << " [ -h | --help ] [ -o <target-file> ] [ -emit-llvm ] [-mem2reg] [-gvn] [-dump-json] <input-file>"
               << std::endl;
 }
 
@@ -20,6 +22,8 @@ int main(int argc, char **argv) {
     std::string input_path;
 
     bool mem2reg = false;
+    bool gvn = false;
+    bool dump_json = false;
     bool emit = false;
 
     for (int i = 1; i < argc; ++i) {
@@ -38,6 +42,10 @@ int main(int argc, char **argv) {
             emit = true;
         } else if (argv[i] == "-mem2reg"s) {
             mem2reg = true;
+        } else if (argv[i] == "-gvn"s) {
+            gvn = true;
+        } else if (argv[i] == "-dump-json"s) {
+            dump_json = true;
         } else {
             if (input_path.empty()) {
                 input_path = argv[i];
@@ -47,6 +55,8 @@ int main(int argc, char **argv) {
             }
         }
     }
+    if (gvn and not mem2reg)
+        LOG_WARNING << "Enabling GVN without mem2reg";
     if (input_path.empty()) {
         print_help(argv[0]);
         return 0;
@@ -77,12 +87,15 @@ int main(int argc, char **argv) {
 
     auto m = builder.getModule();
 
-    m->set_print_name();
+    // m->set_print_name();
     PassManager PM(m.get());
 
     if (mem2reg) {
         PM.add_pass<Mem2Reg>(emit);
     }
+    if (gvn)
+        PM.add_pass<GVN>(emit, dump_json);
+
     PM.run();
 
     auto IR = m->print();
@@ -95,11 +108,13 @@ int main(int argc, char **argv) {
     output_stream << IR;
     output_stream.close();
     if (!emit) {
-        std::string lib_path = argv[0];
+        std::string lib_path = " -L"s + argv[0];
         auto idx = lib_path.rfind('/');
         if (idx != std::string::npos)
-            lib_path.erase(lib_path.rfind('/'));
-        auto cmd_str = "clang -O0 -w "s + target_path + ".ll -o " + target_path + " -L" + lib_path + " -lcminus_io";
+            lib_path.erase(idx);
+        else
+            lib_path.clear();
+        auto cmd_str = "clang -O0 -w -no-pie "s + target_path + ".ll -o " + target_path + lib_path + " -lcminus_io";
         int re_code0 = std::system(cmd_str.c_str());
         cmd_str = "rm "s + target_path + ".ll";
         int re_code1 = std::system(cmd_str.c_str());
@@ -108,5 +123,6 @@ int main(int argc, char **argv) {
         else
             return 1;
     }
+
     return 0;
 }

src/lightir/Value.cpp

@@ -24,3 +24,17 @@ void Value::remove_use(Value *val) {
     auto is_val = [val](const Use &use) { return use.val_ == val; };
     use_list_.remove_if(is_val);
 }
+
+void Value::replace_use_with_when(Value *new_val, std::function<bool(User *)> pred) {
+    for (auto it = use_list_.begin(); it != use_list_.end();) {
+        auto use = *it;
+        auto val = dynamic_cast<User *>(use.val_);
+        assert(val && "new_val is not a user");
+        if (not pred(val)) {
+            ++it;
+            continue;
+        }
+        val->set_operand(use.arg_no_, new_val);
+        it = use_list_.erase(it);
+    }
+}

src/optimization/CMakeLists.txt

@@ -2,4 +2,5 @@ add_library(
         OP_lib STATIC
         Dominators.cpp
         Mem2Reg.cpp
+        GVN.cpp
 )

tests/4-ir-opt/testcases/GVN/functional/bin.cminus

+/* c and d are redundant, and also check for constant propagation */
+int main(void) {
+    int a;
+    int b;
+    int c;
+    int d;
+    if (input() > input()) {
+        a = 33 + 33;
+        b = 44 + 44;
+        c = a + b;
+    } else {
+        a = 55 + 55;
+        b = 66 + 66;
+        c = a + b;
+    }
+    output(c);
+    d = a + b;
+    output(d);
+}

tests/4-ir-opt/testcases/GVN/functional/bin.json

+[
+    {
+        "function": "main",
+        "pout": {
+            "label_entry": [
+                [
+                    "%op0",
+                ],
+                [
+                    "%op1",
+                ],
+                [
+                    "%op2",
+                ],
+                [
+                    "%op3",
+                ],
+                [
+                    "%op4",
+                ],
+            ],
+            "label5": [
+                [
+                    "%op0",
+                ],
+                [
+                    "%op1",
+                ],
+                [
+                    "%op2",
+                ],
+                [
+                    "%op3",
+                ],
+                [
+                    "%op4",
+                ],
+                [
+                    "%op6",
+                    "%op12",
+                ],
+                [
+                    "%op7",
+                    "%op11",
+                ],
+                [
+                    "%op8",
+                    "%op10",
+                ],
+            ],
+            "label9": [
+                [
+                    "%op0",
+                ],
+                [
+                    "%op1",
+                ],
+                [
+                    "%op2",
+                ],
+                [
+                    "%op3",
+                ],
+                [
+                    "%op4",
+                ],
+                [
+                    "%op12",
+                ],
+                [
+                    "%op11",
+                ],
+                [
+                    "%op13",
+                    "%op10",
+                ],
+            ],
+            "label14": [
+                [
+                    "%op0",
+                ],
+                [
+                    "%op1",
+                ],
+                [
+                    "%op2",
+                ],
+                [
+                    "%op3",
+                ],
+                [
+                    "%op4",
+                ],
+                [
+                    "%op15",
+                    "%op12",
+                ],
+                [
+                    "%op16",
+                    "%op11",
+                ],
+                [
+                    "%op17",
+                    "%op10",
+                ],
+            ],
+        }
+    },
+]
\ No newline at end of file

tests/4-ir-opt/testcases/GVN/functional/loop3.cminus

+/* c and d are redundant, e and f are not redundant  */
+int main(void) {
+    int i;
+    int j;
+    int a;
+    int b;
+    int c;
+    int d;
+    int e;
+    int f;
+
+    a = 0;
+    b = 0;
+    c = 0;
+    d = 0;
+    e = 0;
+    f = 0;
+
+    i = 1;
+    while (i < 10) {
+        j = 1;
+        a = input();
+        b = input();
+        c = a + b;
+        while (j < 10) {
+            i = i + j;
+            j = i + j;
+            c = a + b;
+        }
+        d = a + b;
+        i = i + 1;
+
+        e = c + d;
+        output(c);
+        output(d);
+    }
+    f = c + d;
+    output(e);
+    output(f);
+    return 0;
+}

tests/4-ir-opt/testcases/GVN/functional/loop3.json

+[
+    {
+        "function": "main",
+        "pout": {
+            "label_entry": [
+                [
+                    0,
+                    "%op3",
+                    "%op2",
+                    "%op1",
+                ],
+                [
+                    1,
+                    "%op7",
+                ],
+            ],
+            "label0": [
+                [
+                    "%op3",
+                    "%op2",
+                ],
+                [
+                    "%op1",
+                ],
+                [
+                    "%op7",
+                ],
+                [
+                    "%op8",
+                ],
+                [
+                    "%op9",
+                ],
+                [
+                    "%op10",
+                ],
+            ],
+            "label11": [
+                [
+                    "%op3",
+                    "%op2",
+                ],
+                [
+                    "%op1",
+                ],
+                [
+                    "%op20",
+                    "%op7",
+                ],
+                [
+                    "%op8",
+                ],
+                [
+                    "%op9",
+                ],
+                [
+                    "%op10",
+                ],
+                [
+                    "%op12",
+                ],
+                [
+                    "%op13",
+                ],
+                [
+                    "%op14",
+                    "%op18",
+                ],
+                [
+                    1,
+                    "%op19",
+                ],
+            ],
+            "label15": [
+                [
+                    "%op3",
+                    "%op2",
+                ],
+                [
+                    "%op1",
+                ],
+                [
+                    "%op7",
+                ],
+                [
+                    "%op8",
+                ],
+                [
+                    "%op9",
+                ],
+                [
+                    "%op10",
+                ],
+                [
+                    "%op16",
+                ],
+            ],
+            "label17": [
+                [
+                    "%op12",
+                ],
+                [
+                    "%op13",
+                ],
+                [
+                    "%op3",
+                    "%op2",
+                ],
+                [
+                    "%op1",
+                ],
+                [
+                    "%op8",
+                ],
+                [
+                    "%op9",
+                ],
+                [
+                    "%op10",
+                ],
+                [
+                    "%op7",
+                ],
+                [
+                    "%op20",
+                ],
+                [
+                    "%op14",
+                    "%op18",
+                ],
+                [
+                    "%op19",
+                ],
+                [
+                    "%op21",
+                ],
+                [
+                    "%op22",
+                ],
+                [
+                    "%op23",
+                ],
+            ],
+            "label24": [
+                [
+                    "%op12",
+                ],
+                [
+                    "%op13",
+                ],
+                [
+                    "%op3",
+                    "%op2",
+                ],
+                [
+                    "%op1",
+                ],
+                [
+                    "%op8",
+                ],
+                [
+                    "%op9",
+                ],
+                [
+                    "%op10",
+                ],
+                [
+                    "%op7",
+                ],
+                [
+                    "%op14",
+                    "%op27",
+                    "%op18",
+                ],
+                [
+                    "%op21",
+                ],
+                [
+                    "%op22",
+                ],
+                [
+                    "%op23",
+                ],
+                [
+                    "%op25",
+                ],
+                [
+                    "%op26",
+                    "%op19",
+                ],
+                [
+                    "%op20",
+                ],
+            ],
+            "label28": [
+                [
+                    "%op12",
+                ],
+                [
+                    "%op13",
+                ],
+                [
+                    "%op8",
+                ],
+                [
+                    "%op9",
+                ],
+                [
+                    "%op10",
+                ],
+                [
+                    "%op20",
+                ],
+                [
+                    "%op14",
+                    "%op29",
+                    "%op3",
+                    "%op18",
+                    "%op2",
+                ],
+                [
+                    "%op19",
+                ],
+                [
+                    "%op21",
+                ],
+                [
+                    "%op22",
+                ],
+                [
+                    "%op23",
+                ],
+                [
+                    "%op30",
+                    "%op7",
+                ],
+                [
+                    "%op31",
+                    "%op1",
+                ],
+            ],
+        }
+    },
+]
\ No newline at end of file

tests/4-ir-opt/testcases/GVN/functional/pure_func.cminus

+/* `max` is pure, can be detected using FuncInfo */
+int max(int a, int b) {
+    if (a > b)
+        return a;
+    return b;
+}
+
+int a[10000];
+int b[10000];
+
+void inputarray(int a[], int n) {
+    int i;
+    i = 0;
+    while (i < n) {
+        a[i] = input();
+        i = i + 1;
+    }
+}
+
+int main(void) {
+    int i;
+    int n;
+    n = input();
+    inputarray(a, n);
+    inputarray(b, n);
+    i = 0;
+    while (i < n) {
+        int ai;
+        int bi;
+        /* `gep a i` and `max(ai,bi)` are redundant */
+        ai = a[i];
+        bi = b[i];
+        a[i] = max(ai, bi) * max(ai, bi);
+        i = i + 1;
+    }
+    i = 0;
+    while (i < n) {
+        output(a[i]);
+        i = i + 1;
+    }
+}
\ No newline at end of file

tests/4-ir-opt/testcases/GVN/functional/single_bb1.cminus

+/* check GVN on one-block input */
+int main(void) {
+    int a;
+    int b;
+    /* we provide a pure function analysis,
+       input is not side-effect free, so multiple calls to input are considered different */
+    a = input();
+    b = input();
+    output(a + b);
+    output(a + b);
+    return 0;
+}

tests/4-ir-opt/testcases/GVN/functional/single_bb1.json

+[{
+"function": "main", 
+"pout": {"label_entry": [["%op0", ], ["%op1", ], ["%op2", "%op3", ], ],
+}},]
\ No newline at end of file

tests/4-ir-opt/testcases/GVN/performance/baseline/const-prop.in

+100000000

tests/4-ir-opt/testcases/GVN/performance/baseline/const-prop.ll

+declare i32 @input()
+
+declare void @output(i32)
+
+declare void @outputFloat(float)
+
+declare void @neg_idx_except()
+
+define void @main() {
+label_entry:
+  %op0 = call i32 @input()
+  br label %label1
+label1:                                                ; preds = %label_entry, %label11
+  %op2 = phi i32 [ 0, %label_entry ], [ 711082625, %label11 ]
+  %op7 = phi i32 [ 0, %label_entry ], [ %op37, %label11 ]
+  %op8 = icmp slt i32 %op7, %op0
+  %op9 = zext i1 %op8 to i32
+  %op10 = icmp ne i32 %op9, 0
+  br i1 %op10, label %label11, label %label38
+label11:                                                ; preds = %label1
+  %op37 = add i32 %op7, 1
+  br label %label1
+label38:                                                ; preds = %label1
+  call void @output(i32 %op2)
+  ret void
+}

tests/4-ir-opt/testcases/GVN/performance/baseline/transpose.in

+10000000
+30
+2
+5
+4
+25
+8
+125
+16
+625
+32
+3125
+2
+5
+4
+25
+8
+125
+16
+625
+32
+3125
+2
+5
+4
+25
+8
+125
+16
+625
+32
+3125

tests/4-ir-opt/testcases/GVN/performance/baseline/transpose.ll

+; ModuleID = 'cminus'
+source_filename = "./test.cminus"
+
+@matrix = global [20000000 x i32] zeroinitializer
+@ad = global [100000 x i32] zeroinitializer
+@len = global i32 zeroinitializer
+declare i32 @input()
+
+declare void @output(i32)
+
+declare void @outputFloat(float)
+
+declare void @neg_idx_except()
+
+define void @readarray() {
+label_entry:
+  br label %label0
+label0:                                                ; preds = %label_entry, %label11
+  %op1 = phi i32 [ 0, %label_entry ], [ %op13, %label11 ]
+  %op2 = load i32, i32* @len
+  %op3 = icmp slt i32 %op1, %op2
+  %op4 = zext i1 %op3 to i32
+  %op5 = icmp ne i32 %op4, 0
+  br i1 %op5, label %label6, label %label9
+label6:                                                ; preds = %label0
+  %op7 = call i32 @input()
+  %op8 = icmp slt i32 %op1, 0
+  br i1 %op8, label %label10, label %label11
+label9:                                                ; preds = %label0
+  ret void
+label10:                                                ; preds = %label6
+  call void @neg_idx_except()
+  ret void
+label11:                                                ; preds = %label6
+  %op12 = getelementptr [100000 x i32], [100000 x i32]* @ad, i32 0, i32 %op1
+  store i32 %op7, i32* %op12
+  %op13 = add i32 %op1, 1
+  br label %label0
+}
+define i32 @transpose(i32 %arg0, i32* %arg1, i32 %arg2) {
+label_entry:
+  %op4 = sdiv i32 %arg0, %arg2
+  br label %label5
+label5:                                                ; preds = %label_entry, %label25
+  %op8 = phi i32 [ 0, %label_entry ], [ %op26, %label25 ]
+  %op9 = icmp slt i32 %op8, %op4
+  %op10 = zext i1 %op9 to i32
+  %op11 = icmp ne i32 %op10, 0
+  br i1 %op11, label %label12, label %label13
+label12:                                                ; preds = %label5
+  br label %label15
+label13:                                                ; preds = %label5
+  ret i32 -1
+label15:                                                ; preds = %label12, %label29
+  %op17 = phi i32 [ 0, %label12 ], [ %op31, %label29 ]
+  %op18 = icmp slt i32 %op17, %arg2
+  %op19 = zext i1 %op18 to i32
+  %op20 = icmp ne i32 %op19, 0
+  br i1 %op20, label %label21, label %label25
+label21:                                                ; preds = %label15
+  %op22 = icmp slt i32 %op8, %op17
+  %op23 = zext i1 %op22 to i32
+  %op24 = icmp ne i32 %op23, 0
+  br i1 %op24, label %label27, label %label32
+label25:                                                ; preds = %label15
+  %op26 = add i32 %op8, 1
+  br label %label5
+label27:                                                ; preds = %label21
+  %op28 = add i32 %op17, 1
+  br label %label29
+label29:                                                ; preds = %label27, %label57
+  %op31 = phi i32 [ %op28, %label27 ], [ %op59, %label57 ]
+  br label %label15
+label32:                                                ; preds = %label21
+  %op33 = mul i32 %op8, %arg2
+  %op34 = add i32 %op33, %op17
+  %op35 = icmp slt i32 %op34, 0
+  br i1 %op35, label %label36, label %label37
+label36:                                                ; preds = %label32
+  call void @neg_idx_except()
+  ret i32 0
+label37:                                                ; preds = %label32
+  %op38 = getelementptr i32, i32* %arg1, i32 %op34
+  %op39 = load i32, i32* %op38
+  br i1 %op35, label %label43, label %label44
+label43:                                                ; preds = %label37
+  call void @neg_idx_except()
+  ret i32 0
+label44:                                                ; preds = %label37
+  %op46 = load i32, i32* %op38
+  %op47 = mul i32 %op17, %op4
+  %op48 = add i32 %op47, %op8
+  %op49 = icmp slt i32 %op48, 0
+  br i1 %op49, label %label50, label %label51
+label50:                                                ; preds = %label44
+  call void @neg_idx_except()
+  ret i32 0
+label51:                                                ; preds = %label44
+  %op52 = getelementptr i32, i32* %arg1, i32 %op48
+  store i32 %op46, i32* %op52
+  br i1 %op35, label %label56, label %label57
+label56:                                                ; preds = %label51
+  call void @neg_idx_except()
+  ret i32 0
+label57:                                                ; preds = %label51
+  store i32 %op39, i32* %op38
+  %op59 = add i32 %op17, 1
+  br label %label29
+}
+define i32 @main() {
+label_entry:
+  %op0 = call i32 @input()
+  %op1 = call i32 @input()
+  store i32 %op1, i32* @len
+  call void @readarray()
+  br label %label2
+label2:                                                ; preds = %label_entry, %label11
+  %op3 = phi i32 [ 0, %label_entry ], [ %op13, %label11 ]
+  %op4 = icmp slt i32 %op3, %op0
+  %op5 = zext i1 %op4 to i32
+  %op6 = icmp ne i32 %op5, 0
+  br i1 %op6, label %label7, label %label9
+label7:                                                ; preds = %label2
+  %op8 = icmp slt i32 %op3, 0
+  br i1 %op8, label %label10, label %label11
+label9:                                                ; preds = %label2
+  br label %label14
+label10:                                                ; preds = %label7
+  call void @neg_idx_except()
+  ret i32 0
+label11:                                                ; preds = %label7
+  %op12 = getelementptr [20000000 x i32], [20000000 x i32]* @matrix, i32 0, i32 %op3
+  store i32 %op3, i32* %op12
+  %op13 = add i32 %op3, 1
+  br label %label2
+label14:                                                ; preds = %label9, %label25
+  %op15 = phi i32 [ 0, %label9 ], [ %op29, %label25 ]
+  %op16 = load i32, i32* @len
+  %op17 = icmp slt i32 %op15, %op16
+  %op18 = zext i1 %op17 to i32
+  %op19 = icmp ne i32 %op18, 0
+  br i1 %op19, label %label20, label %label23
+label20:                                                ; preds = %label14
+  %op21 = getelementptr [20000000 x i32], [20000000 x i32]* @matrix, i32 0, i32 0
+  %op22 = icmp slt i32 %op15, 0
+  br i1 %op22, label %label24, label %label25
+label23:                                                ; preds = %label14
+  br label %label30
+label24:                                                ; preds = %label20
+  call void @neg_idx_except()
+  ret i32 0
+label25:                                                ; preds = %label20
+  %op26 = getelementptr [100000 x i32], [100000 x i32]* @ad, i32 0, i32 %op15
+  %op27 = load i32, i32* %op26
+  %op28 = call i32 @transpose(i32 %op0, i32* %op21, i32 %op27)
+  %op29 = add i32 %op15, 1
+  br label %label14
+label30:                                                ; preds = %label23, %label45
+  %op31 = phi i32 [ 0, %label23 ], [ %op49, %label45 ]
+  %op32 = phi i32 [ 0, %label23 ], [ %op50, %label45 ]
+  %op33 = load i32, i32* @len
+  %op34 = icmp slt i32 %op32, %op33
+  %op35 = zext i1 %op34 to i32
+  %op36 = icmp ne i32 %op35, 0
+  br i1 %op36, label %label37, label %label40
+label37:                                                ; preds = %label30
+  %op38 = mul i32 %op32, %op32
+  %op39 = icmp slt i32 %op32, 0
+  br i1 %op39, label %label44, label %label45
+label40:                                                ; preds = %label30
+  %op41 = icmp slt i32 %op31, 0
+  %op42 = zext i1 %op41 to i32
+  %op43 = icmp ne i32 %op42, 0
+  br i1 %op43, label %label51, label %label53
+label44:                                                ; preds = %label37
+  call void @neg_idx_except()
+  ret i32 0
+label45:                                                ; preds = %label37
+  %op46 = getelementptr [20000000 x i32], [20000000 x i32]* @matrix, i32 0, i32 %op32
+  %op47 = load i32, i32* %op46
+  %op48 = mul i32 %op38, %op47
+  %op49 = add i32 %op31, %op48
+  %op50 = add i32 %op32, 1
+  br label %label30
+label51:                                                ; preds = %label40
+  %op52 = sub i32 0, %op31
+  br label %label53
+label53:                                                ; preds = %label40, %label51
+  %op54 = phi i32 [ %op31, %label40 ], [ %op52, %label51 ]
+  call void @output(i32 %op54)
+  ret i32 0
+}

tests/4-ir-opt/testcases/GVN/performance/const-prop.cminus

+void main(void) {
+    int c;
+    int a;
+    int b;
+    int d;
+    int f;
+    int g;
+    int loopCnt;
+    loopCnt = input();
+    c = 0;
+    a = 0;
+    g = 0;
+    while (c < loopCnt) {
+        a = 1.23456 * 5.73478 * 2.3333 * 4.3673 * 6.34636;
+        b = a * a * a * a * a * a;
+        d = b * b * b * b * b * b;
+        f = d * d * d * d * d * d;
+        g = f * f * f * f * f * f;
+        c = c + 1;
+    }
+    output(g);
+    return;
+}
\ No newline at end of file

tests/4-ir-opt/testcases/GVN/performance/const-prop.in

+100000000

tests/4-ir-opt/testcases/GVN/performance/const-prop.out

+711082625

tests/4-ir-opt/testcases/GVN/performance/transpose.cminus

+int matrix[20000000];
+int ad[100000];
+
+int len;
+
+void readarray(void) {
+    int cnt;
+    cnt = 0;
+    while (cnt < len) {
+        ad[cnt] = input();
+        cnt = cnt + 1;
+    }
+}
+
+int transpose(int n, int matrix[], int rowsize) {
+    int colsize;
+    int i;
+    int j;
+    int curr;
+    colsize = n / rowsize;
+    i = 0;
+    j = 0;
+    while (i < colsize) {
+        j = 0;
+        while (j < rowsize) {
+            if (i < j) {
+                j = j + 1;
+            } else {
+                curr = matrix[i * rowsize + j];
+                matrix[j * colsize + i] = matrix[i * rowsize + j];
+                matrix[i * rowsize + j] = curr;
+                j = j + 1;
+            }
+        }
+        i = i + 1;
+    }
+    return 0 - 1;
+}
+
+int main(void) {
+    int n;
+    int i;
+    int ans;
+    n = input();
+    len = input();
+    readarray();
+    i = 0;
+
+    while (i < n) {
+        matrix[i] = i;
+        i = i + 1;
+    }
+    i = 0;
+    while (i < len) {
+        transpose(n, matrix, ad[i]);
+        i = i + 1;
+    }
+
+    ans = 0;
+    i = 0;
+    while (i < len) {
+        ans = ans + i * i * matrix[i];
+        i = i + 1;
+    }
+    if (ans < 0) {
+        ans = 0 - ans;
+    }
+    output(ans);
+    return 0;
+}

tests/4-ir-opt/testcases/GVN/performance/transpose.in

+10000000
+30
+2
+5
+4
+25
+8
+125
+16
+625
+32
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tests/4-ir-opt/testcases/GVN/performance/transpose.out

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