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//===-- SILowerI1Copies.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
/// Interface definition of the PhiLoweringHelper class that implements lane
/// mask merging algorithm for divergent i1 phis.
//
//===----------------------------------------------------------------------===//
#include "GCNSubtarget.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachinePostDominators.h"
#include "llvm/CodeGen/MachineSSAUpdater.h"
namespace llvm {
/// Incoming for lane maks phi as machine instruction, incoming register \p Reg
/// and incoming block \p Block are taken from machine instruction.
/// \p UpdatedReg (if valid) is \p Reg lane mask merged with another lane mask.
struct Incoming {
Register Reg;
MachineBasicBlock *Block;
Register UpdatedReg;
Incoming(Register Reg, MachineBasicBlock *Block, Register UpdatedReg)
: Reg(Reg), Block(Block), UpdatedReg(UpdatedReg) {}
};
Register createLaneMaskReg(MachineRegisterInfo *MRI,
MachineRegisterInfo::VRegAttrs LaneMaskRegAttrs);
class PhiLoweringHelper {
public:
PhiLoweringHelper(MachineFunction *MF, MachineDominatorTree *DT,
MachinePostDominatorTree *PDT);
virtual ~PhiLoweringHelper() = default;
protected:
bool IsWave32 = false;
MachineFunction *MF = nullptr;
MachineDominatorTree *DT = nullptr;
MachinePostDominatorTree *PDT = nullptr;
MachineRegisterInfo *MRI = nullptr;
const GCNSubtarget *ST = nullptr;
const SIInstrInfo *TII = nullptr;
MachineRegisterInfo::VRegAttrs LaneMaskRegAttrs;
#ifndef NDEBUG
DenseSet<Register> PhiRegisters;
#endif
Register ExecReg;
unsigned MovOp;
unsigned AndOp;
unsigned OrOp;
unsigned XorOp;
unsigned AndN2Op;
unsigned OrN2Op;
public:
bool lowerPhis();
bool isConstantLaneMask(Register Reg, bool &Val) const;
MachineBasicBlock::iterator
getSaluInsertionAtEnd(MachineBasicBlock &MBB) const;
void initializeLaneMaskRegisterAttributes(Register LaneMask) {
LaneMaskRegAttrs = MRI->getVRegAttrs(LaneMask);
}
bool isLaneMaskReg(Register Reg) const {
return TII->getRegisterInfo().isSGPRReg(*MRI, Reg) &&
TII->getRegisterInfo().getRegSizeInBits(Reg, *MRI) ==
ST->getWavefrontSize();
}
// Helpers from lowerPhis that are different between sdag and global-isel.
virtual void markAsLaneMask(Register DstReg) const = 0;
virtual void getCandidatesForLowering(
SmallVectorImpl<MachineInstr *> &Vreg1Phis) const = 0;
virtual void
collectIncomingValuesFromPhi(const MachineInstr *MI,
SmallVectorImpl<Incoming> &Incomings) const = 0;
virtual void replaceDstReg(Register NewReg, Register OldReg,
MachineBasicBlock *MBB) = 0;
virtual void buildMergeLaneMasks(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
const DebugLoc &DL, Register DstReg,
Register PrevReg, Register CurReg) = 0;
virtual void constrainAsLaneMask(Incoming &In) = 0;
};
} // end namespace llvm
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