110 lines
4.8 KiB
C
110 lines
4.8 KiB
C
|
//===-- llvm/CodeGen/GlobalISel/CSEMIRBuilder.h --*- 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
|
||
|
|
//
|
||
|
|
//===----------------------------------------------------------------------===//
|
||
|
|
/// \file
|
||
|
|
/// This file implements a version of MachineIRBuilder which CSEs insts within
|
||
|
|
/// a MachineBasicBlock.
|
||
|
|
//===----------------------------------------------------------------------===//
|
||
|
|
#ifndef LLVM_CODEGEN_GLOBALISEL_CSEMIRBUILDER_H
|
||
|
|
#define LLVM_CODEGEN_GLOBALISEL_CSEMIRBUILDER_H
|
||
|
|
|
||
|
|
#include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
|
||
|
|
#include "llvm/CodeGen/GlobalISel/Utils.h"
|
||
|
|
|
||
|
|
namespace llvm {
|
||
|
|
|
||
|
|
/// Defines a builder that does CSE of MachineInstructions using GISelCSEInfo.
|
||
|
|
/// Eg usage.
|
||
|
|
///
|
||
|
|
///
|
||
|
|
/// GISelCSEInfo *Info =
|
||
|
|
/// &getAnalysis<GISelCSEAnalysisWrapperPass>().getCSEInfo(); CSEMIRBuilder
|
||
|
|
/// CB(Builder.getState()); CB.setCSEInfo(Info); auto A = CB.buildConstant(s32,
|
||
|
|
/// 42); auto B = CB.buildConstant(s32, 42); assert(A == B); unsigned CReg =
|
||
|
|
/// MRI.createGenericVirtualRegister(s32); auto C = CB.buildConstant(CReg, 42);
|
||
|
|
/// assert(C->getOpcode() == TargetOpcode::COPY);
|
||
|
|
/// Explicitly passing in a register would materialize a copy if possible.
|
||
|
|
/// CSEMIRBuilder also does trivial constant folding for binary ops.
|
||
|
|
class CSEMIRBuilder : public MachineIRBuilder {
|
||
|
|
|
||
|
|
/// Returns true if A dominates B (within the same basic block).
|
||
|
|
/// Both iterators must be in the same basic block.
|
||
|
|
//
|
||
|
|
// TODO: Another approach for checking dominance is having two iterators and
|
||
|
|
// making them go towards each other until they meet or reach begin/end. Which
|
||
|
|
// approach is better? Should this even change dynamically? For G_CONSTANTS
|
||
|
|
// most of which will be at the top of the BB, the top down approach would be
|
||
|
|
// a better choice. Does IRTranslator placing constants at the beginning still
|
||
|
|
// make sense? Should this change based on Opcode?
|
||
|
|
bool dominates(MachineBasicBlock::const_iterator A,
|
||
|
|
MachineBasicBlock::const_iterator B) const;
|
||
|
|
|
||
|
|
/// For given ID, find a machineinstr in the CSE Map. If found, check if it
|
||
|
|
/// dominates the current insertion point and if not, move it just before the
|
||
|
|
/// current insertion point and return it. If not found, return Null
|
||
|
|
/// MachineInstrBuilder.
|
||
|
|
MachineInstrBuilder getDominatingInstrForID(FoldingSetNodeID &ID,
|
||
|
|
void *&NodeInsertPos);
|
||
|
|
/// Simple check if we can CSE (we have the CSEInfo) or if this Opcode is
|
||
|
|
/// safe to CSE.
|
||
|
|
bool canPerformCSEForOpc(unsigned Opc) const;
|
||
|
|
|
||
|
|
void profileDstOp(const DstOp &Op, GISelInstProfileBuilder &B) const;
|
||
|
|
|
||
|
|
void profileDstOps(ArrayRef<DstOp> Ops, GISelInstProfileBuilder &B) const {
|
||
|
|
for (const DstOp &Op : Ops)
|
||
|
|
profileDstOp(Op, B);
|
||
|
|
}
|
||
|
|
|
||
|
|
void profileSrcOp(const SrcOp &Op, GISelInstProfileBuilder &B) const;
|
||
|
|
|
||
|
|
void profileSrcOps(ArrayRef<SrcOp> Ops, GISelInstProfileBuilder &B) const {
|
||
|
|
for (const SrcOp &Op : Ops)
|
||
|
|
profileSrcOp(Op, B);
|
||
|
|
}
|
||
|
|
|
||
|
|
void profileMBBOpcode(GISelInstProfileBuilder &B, unsigned Opc) const;
|
||
|
|
|
||
|
|
void profileEverything(unsigned Opc, ArrayRef<DstOp> DstOps,
|
||
|
|
ArrayRef<SrcOp> SrcOps, Optional<unsigned> Flags,
|
||
|
|
GISelInstProfileBuilder &B) const;
|
||
|
|
|
||
|
|
// Takes a MachineInstrBuilder and inserts it into the CSEMap using the
|
||
|
|
// NodeInsertPos.
|
||
|
|
MachineInstrBuilder memoizeMI(MachineInstrBuilder MIB, void *NodeInsertPos);
|
||
|
|
|
||
|
|
// If we have can CSE an instruction, but still need to materialize to a VReg,
|
||
|
|
// we emit a copy from the CSE'd inst to the VReg.
|
||
|
|
MachineInstrBuilder generateCopiesIfRequired(ArrayRef<DstOp> DstOps,
|
||
|
|
MachineInstrBuilder &MIB);
|
||
|
|
|
||
|
|
// If we have can CSE an instruction, but still need to materialize to a VReg,
|
||
|
|
// check if we can generate copies. It's not possible to return a single MIB,
|
||
|
|
// while emitting copies to multiple vregs.
|
||
|
|
bool checkCopyToDefsPossible(ArrayRef<DstOp> DstOps);
|
||
|
|
|
||
|
|
public:
|
||
|
|
// Pull in base class constructors.
|
||
|
|
using MachineIRBuilder::MachineIRBuilder;
|
||
|
|
// Unhide buildInstr
|
||
|
|
MachineInstrBuilder buildInstr(unsigned Opc, ArrayRef<DstOp> DstOps,
|
||
|
|
ArrayRef<SrcOp> SrcOps,
|
||
|
|
Optional<unsigned> Flag = None) override;
|
||
|
|
// Bring in the other overload from the base class.
|
||
|
|
using MachineIRBuilder::buildConstant;
|
||
|
|
|
||
|
|
MachineInstrBuilder buildConstant(const DstOp &Res,
|
||
|
|
const ConstantInt &Val) override;
|
||
|
|
|
||
|
|
// Bring in the other overload from the base class.
|
||
|
|
using MachineIRBuilder::buildFConstant;
|
||
|
|
MachineInstrBuilder buildFConstant(const DstOp &Res,
|
||
|
|
const ConstantFP &Val) override;
|
||
|
|
};
|
||
|
|
} // namespace llvm
|
||
|
|
#endif
|