Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

//===- SelectionDAGAddressAnalysis.h - DAG Address Analysis -----*- C++ -*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_CODEGEN_SELECTIONDAGADDRESSANALYSIS_H

#define LLVM_CODEGEN_SELECTIONDAGADDRESSANALYSIS_H

#include "llvm/CodeGen/SelectionDAGNodes.h"

#include <cstdint>

namespace llvm {

class SelectionDAG;

/// Helper struct to parse and store a memory address as base + index + offset.

/// We ignore sign extensions when it is safe to do so.

/// The following two expressions are not equivalent. To differentiate we need

/// to store whether there was a sign extension involved in the index

/// computation.

///  (load (i64 add (i64 copyfromreg %c)

///                 (i64 signextend (add (i8 load %index)

///                                      (i8 1))))

/// vs

///

/// (load (i64 add (i64 copyfromreg %c)

///                (i64 signextend (i32 add (i32 signextend (i8 load %index))

///                                         (i32 1)))))

class BaseIndexOffset {

private:

  SDValue Base;

  SDValue Index;

  std::optional<int64_t> Offset;

  bool IsIndexSignExt = false;

public:

  BaseIndexOffset() = default;

  BaseIndexOffset(SDValue Base, SDValue Index, bool IsIndexSignExt)

      : Base(Base), Index(Index), IsIndexSignExt(IsIndexSignExt) {}

  BaseIndexOffset(SDValue Base, SDValue Index, int64_t Offset,

                  bool IsIndexSignExt)

      : Base(Base), Index(Index), Offset(Offset),

        IsIndexSignExt(IsIndexSignExt) {}

  SDValue getBase() { return Base; }

  SDValue getBase() const { return Base; }

  SDValue getIndex() { return Index; }

  SDValue getIndex() const { return Index; }

  void addToOffset(int64_t VectorOff) {

    Offset = Offset.value_or(0) + VectorOff;

  }

  bool hasValidOffset() const { return Offset.has_value(); }

  int64_t getOffset() const { return *Offset; }

  // Returns true if `Other` and `*this` are both some offset from the same base

  // pointer. In that case, `Off` is set to the offset between `*this` and

  // `Other` (negative if `Other` is before `*this`).

  bool equalBaseIndex(const BaseIndexOffset &Other, const SelectionDAG &DAG,

                      int64_t &Off) const;

  bool equalBaseIndex(const BaseIndexOffset &Other,

                      const SelectionDAG &DAG) const {

    int64_t Off;

    return equalBaseIndex(Other, DAG, Off);

  }

  // Returns true if `Other` (with size `OtherSize`) can be proven to be fully

  // contained in `*this` (with size `Size`).

  bool contains(const SelectionDAG &DAG, int64_t BitSize,

                const BaseIndexOffset &Other, int64_t OtherBitSize,

                int64_t &BitOffset) const;

  bool contains(const SelectionDAG &DAG, int64_t BitSize,

                const BaseIndexOffset &Other, int64_t OtherBitSize) const {

    int64_t BitOffset;

    return contains(DAG, BitSize, Other, OtherBitSize, BitOffset);

  }

  // Returns true `Op0` and `Op1` can be proven to alias/not alias, in

  // which case `IsAlias` is set to true/false.

  static bool computeAliasing(const SDNode *Op0,

                              const std::optional<int64_t> NumBytes0,

                              const SDNode *Op1,

                              const std::optional<int64_t> NumBytes1,

                              const SelectionDAG &DAG, bool &IsAlias);

  /// Parses tree in N for base, index, offset addresses.

  static BaseIndexOffset match(const SDNode *N, const SelectionDAG &DAG);

  void print(raw_ostream& OS) const;

  void dump() const;

};

} // end namespace llvm

#endif // LLVM_CODEGEN_SELECTIONDAGADDRESSANALYSIS_H