96 lines
3.6 KiB
C++
96 lines
3.6 KiB
C++
//===- SelectionDAGAddressAnalysis.h - DAG Address Analysis -----*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CODEGEN_SELECTIONDAGADDRESSANALYSIS_H
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#define LLVM_CODEGEN_SELECTIONDAGADDRESSANALYSIS_H
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#include "llvm/CodeGen/SelectionDAGNodes.h"
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#include <cstdint>
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namespace llvm {
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class SelectionDAG;
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/// Helper struct to parse and store a memory address as base + index + offset.
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/// We ignore sign extensions when it is safe to do so.
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/// The following two expressions are not equivalent. To differentiate we need
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/// to store whether there was a sign extension involved in the index
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/// computation.
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/// (load (i64 add (i64 copyfromreg %c)
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/// (i64 signextend (add (i8 load %index)
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/// (i8 1))))
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/// vs
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///
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/// (load (i64 add (i64 copyfromreg %c)
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/// (i64 signextend (i32 add (i32 signextend (i8 load %index))
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/// (i32 1)))))
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class BaseIndexOffset {
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private:
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SDValue Base;
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SDValue Index;
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Optional<int64_t> Offset;
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bool IsIndexSignExt = false;
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public:
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BaseIndexOffset() = default;
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BaseIndexOffset(SDValue Base, SDValue Index, bool IsIndexSignExt)
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: Base(Base), Index(Index), Offset(), IsIndexSignExt(IsIndexSignExt) {}
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BaseIndexOffset(SDValue Base, SDValue Index, int64_t Offset,
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bool IsIndexSignExt)
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: Base(Base), Index(Index), Offset(Offset),
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IsIndexSignExt(IsIndexSignExt) {}
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SDValue getBase() { return Base; }
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SDValue getBase() const { return Base; }
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SDValue getIndex() { return Index; }
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SDValue getIndex() const { return Index; }
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bool hasValidOffset() const { return Offset.hasValue(); }
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// Returns true if `Other` and `*this` are both some offset from the same base
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// pointer. In that case, `Off` is set to the offset between `*this` and
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// `Other` (negative if `Other` is before `*this`).
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bool equalBaseIndex(const BaseIndexOffset &Other, const SelectionDAG &DAG,
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int64_t &Off) const;
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bool equalBaseIndex(const BaseIndexOffset &Other,
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const SelectionDAG &DAG) const {
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int64_t Off;
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return equalBaseIndex(Other, DAG, Off);
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}
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// Returns true if `Other` (with size `OtherSize`) can be proven to be fully
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// contained in `*this` (with size `Size`).
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bool contains(const SelectionDAG &DAG, int64_t BitSize,
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const BaseIndexOffset &Other, int64_t OtherBitSize,
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int64_t &BitOffset) const;
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bool contains(const SelectionDAG &DAG, int64_t BitSize,
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const BaseIndexOffset &Other, int64_t OtherBitSize) const {
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int64_t BitOffset;
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return contains(DAG, BitSize, Other, OtherBitSize, BitOffset);
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}
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// Returns true `Op0` and `Op1` can be proven to alias/not alias, in
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// which case `IsAlias` is set to true/false.
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static bool computeAliasing(const SDNode *Op0,
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const Optional<int64_t> NumBytes0,
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const SDNode *Op1,
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const Optional<int64_t> NumBytes1,
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const SelectionDAG &DAG, bool &IsAlias);
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/// Parses tree in N for base, index, offset addresses.
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static BaseIndexOffset match(const SDNode *N, const SelectionDAG &DAG);
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void print(raw_ostream& OS) const;
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void dump() const;
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};
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} // end namespace llvm
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#endif // LLVM_CODEGEN_SELECTIONDAGADDRESSANALYSIS_H
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