remove_dead_var.h

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#ifndef FREE_TENSOR_REMOVE_DEAD_VAR_H
#define FREE_TENSOR_REMOVE_DEAD_VAR_H
 
#include <unordered_set>
 
#include <analyze/symbol_table.h>
#include <func.h>
#include <mutator.h>
 
namespace freetensor {
 
class RemoveAllWrites : public Mutator {
    std::string var_;
 
  public:
    RemoveAllWrites(const std::string &var) : var_(var) {}
 
  protected:
    Stmt visit(const Store &op) override;
    Stmt visit(const ReduceTo &op) override;
};
 
class RemoveDeadVar : public SymbolTable<Mutator> {
    typedef SymbolTable<Mutator> BaseClass;
 
    // All reads occured from the current statement to the last statement
    std::unordered_set<std::string> readsAfterward_;
 
    // All writes occured in each statemtns
    std::unordered_map<ID, std::unordered_set<std::string>> writes_;
 
    std::unordered_set<std::string> writtenToOutput_;
    std::unordered_map<std::string, int> inLoopCnt_;
    std::string destination_;
    bool isFixPoint_ = true;
 
  public:
    bool isFixPoint() const { return isFixPoint_; }
 
  protected:
    using BaseClass::visit;
    Stmt visitStmt(const Stmt &s) override;
    Expr visit(const Load &op) override;
    Stmt visit(const Store &op) override;
    Stmt visit(const ReduceTo &op) override;
    Stmt visit(const VarDef &op) override;
    Stmt visit(const For &op) override;
    Stmt visit(const StmtSeq &op) override;
};
 
Stmt removeDeadVar(const Stmt &op);
 
DEFINE_PASS_FOR_FUNC(removeDeadVar)
 
} // namespace freetensor
 
#endif // FREE_TENSOR_REMOVE_DEAD_VAR_H