strengthReduction.h

/*
Copyright 2013-present Barefoot Networks, Inc.
 
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
 
    http://www.apache.org/licenses/LICENSE-2.0
 
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
 
#ifndef P4_STRENGTHREDUCTION_H_
#define P4_STRENGTHREDUCTION_H_
 
#include "frontends/common/resolveReferences/referenceMap.h"
#include "frontends/p4/sideEffects.h"
#include "frontends/p4/typeChecking/typeChecker.h"
#include "frontends/p4/typeMap.h"
#include "ir/ir.h"
 
namespace P4 {
 
class DoStrengthReduction final : public Transform {
    bool isOne(const IR::Expression *expr) const;
    bool isZero(const IR::Expression *expr) const;
    bool isTrue(const IR::Expression *expr) const;
    bool isFalse(const IR::Expression *expr) const;
    bool isAllOnes(const IR::Expression *expr) const;
    int isPowerOf2(const IR::Expression *expr) const;
 
    bool hasSideEffects(const IR::Expression *expr) const {
        return SideEffects::check(expr, this, nullptr, nullptr);
    }
 
 public:
    DoStrengthReduction() {
        visitDagOnce = true;
        setName("StrengthReduction");
    }
 
    using Transform::postorder;
 
    const IR::Node *postorder(IR::Cmpl *expr) override;
    const IR::Node *postorder(IR::BAnd *expr) override;
    const IR::Node *postorder(IR::BOr *expr) override;
    const IR::Node *postorder(IR::Equ *expr) override;
    const IR::Node *postorder(IR::Neq *expr) override;
    const IR::Node *postorder(IR::BXor *expr) override;
    const IR::Node *postorder(IR::LAnd *expr) override;
    const IR::Node *postorder(IR::LOr *expr) override;
    const IR::Node *postorder(IR::LNot *expr) override;
    const IR::Node *postorder(IR::Sub *expr) override;
    const IR::Node *postorder(IR::Add *expr) override;
    const IR::Node *postorder(IR::UPlus *expr) override;
    const IR::Node *postorder(IR::Shl *expr) override;
    const IR::Node *postorder(IR::Shr *expr) override;
    const IR::Node *postorder(IR::Mul *expr) override;
    const IR::Node *postorder(IR::Div *expr) override;
    const IR::Node *postorder(IR::Mod *expr) override;
    const IR::Node *postorder(IR::Mux *expr) override;
    const IR::Node *postorder(IR::Slice *expr) override;
    const IR::Node *postorder(IR::Mask *expr) override;
    const IR::Node *postorder(IR::Range *expr) override;
    const IR::Node *postorder(IR::Concat *expr) override;
    const IR::Node *postorder(IR::ArrayIndex *expr) override;
 
    const IR::BlockStatement *preorder(IR::BlockStatement *bs) override {
        if (bs->annotations->getSingle("disable_optimization")) prune();
        return bs;
    }
};
 
class StrengthReduction : public PassManager {
 public:
    StrengthReduction(ReferenceMap *refMap, TypeMap *typeMap,
                      TypeChecking *typeChecking = nullptr) {
        if (typeMap != nullptr) {
            if (!typeChecking) typeChecking = new TypeChecking(refMap, typeMap, true);
            passes.push_back(typeChecking);
        }
        passes.push_back(new DoStrengthReduction());
    }
};
 
}  // namespace P4
 
#endif /* P4_STRENGTHREDUCTION_H_ */