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| //===- 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;
Optional<int64_t> Offset;
bool IsIndexSignExt = false;
public:
BaseIndexOffset() = default;
BaseIndexOffset(SDValue Base, SDValue Index, bool IsIndexSignExt)
: Base(Base), Index(Index), Offset(), 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; }
bool hasValidOffset() const { return Offset.hasValue(); }
// 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 Optional<int64_t> NumBytes0,
const SDNode *Op1,
const 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
|