llvm-project/llvm/lib/Target/AArch64/AArch64MacroFusion.cpp

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6.7 KiB
C++

//===- AArch64MacroFusion.cpp - AArch64 Macro Fusion ----------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
/// \file This file contains the AArch64 implementation of the DAG scheduling
/// mutation to pair instructions back to back.
//
//===----------------------------------------------------------------------===//
#include "AArch64Subtarget.h"
#include "llvm/CodeGen/MacroFusion.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
using namespace llvm;
namespace {
/// \brief Check if the instr pair, FirstMI and SecondMI, should be fused
/// together. Given SecondMI, when FirstMI is unspecified, then check if
/// SecondMI may be part of a fused pair at all.
static bool shouldScheduleAdjacent(const TargetInstrInfo &TII,
const TargetSubtargetInfo &TSI,
const MachineInstr *FirstMI,
const MachineInstr &SecondMI) {
const AArch64InstrInfo &II = static_cast<const AArch64InstrInfo&>(TII);
const AArch64Subtarget &ST = static_cast<const AArch64Subtarget&>(TSI);
// Assume wildcards for unspecified instrs.
unsigned FirstOpcode =
FirstMI ? FirstMI->getOpcode()
: static_cast<unsigned>(AArch64::INSTRUCTION_LIST_END);
unsigned SecondOpcode = SecondMI.getOpcode();
if (ST.hasArithmeticBccFusion())
// Fuse CMN, CMP, TST followed by Bcc.
if (SecondOpcode == AArch64::Bcc)
switch (FirstOpcode) {
default:
return false;
case AArch64::ADDSWri:
case AArch64::ADDSWrr:
case AArch64::ADDSXri:
case AArch64::ADDSXrr:
case AArch64::ANDSWri:
case AArch64::ANDSWrr:
case AArch64::ANDSXri:
case AArch64::ANDSXrr:
case AArch64::SUBSWri:
case AArch64::SUBSWrr:
case AArch64::SUBSXri:
case AArch64::SUBSXrr:
case AArch64::BICSWrr:
case AArch64::BICSXrr:
return true;
case AArch64::ADDSWrs:
case AArch64::ADDSXrs:
case AArch64::ANDSWrs:
case AArch64::ANDSXrs:
case AArch64::SUBSWrs:
case AArch64::SUBSXrs:
case AArch64::BICSWrs:
case AArch64::BICSXrs:
// Shift value can be 0 making these behave like the "rr" variant...
return !II.hasShiftedReg(*FirstMI);
case AArch64::INSTRUCTION_LIST_END:
return true;
}
if (ST.hasArithmeticCbzFusion())
// Fuse ALU operations followed by CBZ/CBNZ.
if (SecondOpcode == AArch64::CBNZW || SecondOpcode == AArch64::CBNZX ||
SecondOpcode == AArch64::CBZW || SecondOpcode == AArch64::CBZX)
switch (FirstOpcode) {
default:
return false;
case AArch64::ADDWri:
case AArch64::ADDWrr:
case AArch64::ADDXri:
case AArch64::ADDXrr:
case AArch64::ANDWri:
case AArch64::ANDWrr:
case AArch64::ANDXri:
case AArch64::ANDXrr:
case AArch64::EORWri:
case AArch64::EORWrr:
case AArch64::EORXri:
case AArch64::EORXrr:
case AArch64::ORRWri:
case AArch64::ORRWrr:
case AArch64::ORRXri:
case AArch64::ORRXrr:
case AArch64::SUBWri:
case AArch64::SUBWrr:
case AArch64::SUBXri:
case AArch64::SUBXrr:
return true;
case AArch64::ADDWrs:
case AArch64::ADDXrs:
case AArch64::ANDWrs:
case AArch64::ANDXrs:
case AArch64::SUBWrs:
case AArch64::SUBXrs:
case AArch64::BICWrs:
case AArch64::BICXrs:
// Shift value can be 0 making these behave like the "rr" variant...
return !II.hasShiftedReg(*FirstMI);
case AArch64::INSTRUCTION_LIST_END:
return true;
}
if (ST.hasFuseAES())
// Fuse AES crypto operations.
switch(SecondOpcode) {
// AES encode.
case AArch64::AESMCrr:
case AArch64::AESMCrrTied:
return FirstOpcode == AArch64::AESErr ||
FirstOpcode == AArch64::INSTRUCTION_LIST_END;
// AES decode.
case AArch64::AESIMCrr:
case AArch64::AESIMCrrTied:
return FirstOpcode == AArch64::AESDrr ||
FirstOpcode == AArch64::INSTRUCTION_LIST_END;
}
if (ST.hasFuseLiterals())
// Fuse literal generation operations.
switch (SecondOpcode) {
// PC relative address.
case AArch64::ADDXri:
return FirstOpcode == AArch64::ADRP ||
FirstOpcode == AArch64::INSTRUCTION_LIST_END;
// 32 bit immediate.
case AArch64::MOVKWi:
return (FirstOpcode == AArch64::MOVZWi &&
SecondMI.getOperand(3).getImm() == 16) ||
FirstOpcode == AArch64::INSTRUCTION_LIST_END;
// Lower and upper half of 64 bit immediate.
case AArch64::MOVKXi:
return FirstOpcode == AArch64::INSTRUCTION_LIST_END ||
(FirstOpcode == AArch64::MOVZXi &&
SecondMI.getOperand(3).getImm() == 16) ||
(FirstOpcode == AArch64::MOVKXi &&
FirstMI->getOperand(3).getImm() == 32 &&
SecondMI.getOperand(3).getImm() == 48);
}
if (ST.hasFuseAddress()) {
// Fuse address generation and loads and stores.
if ((FirstOpcode == AArch64::INSTRUCTION_LIST_END ||
FirstOpcode == AArch64::ADR ||
FirstOpcode == AArch64::ADRP) &&
((SecondOpcode == AArch64::STRBBui ||
SecondOpcode == AArch64::STRBui ||
SecondOpcode == AArch64::STRDui ||
SecondOpcode == AArch64::STRHHui ||
SecondOpcode == AArch64::STRHui ||
SecondOpcode == AArch64::STRQui ||
SecondOpcode == AArch64::STRSui ||
SecondOpcode == AArch64::STRWui ||
SecondOpcode == AArch64::STRXui ||
SecondOpcode == AArch64::LDRBBui ||
SecondOpcode == AArch64::LDRBui ||
SecondOpcode == AArch64::LDRDui ||
SecondOpcode == AArch64::LDRHHui ||
SecondOpcode == AArch64::LDRHui ||
SecondOpcode == AArch64::LDRQui ||
SecondOpcode == AArch64::LDRSBWui ||
SecondOpcode == AArch64::LDRSBXui ||
SecondOpcode == AArch64::LDRSHWui ||
SecondOpcode == AArch64::LDRSHXui ||
SecondOpcode == AArch64::LDRSWui ||
SecondOpcode == AArch64::LDRSui ||
SecondOpcode == AArch64::LDRWui ||
SecondOpcode == AArch64::LDRXui) &&
(FirstOpcode != AArch64::ADR ||
SecondMI.getOperand(2).getImm() == 0)))
return true;
}
return false;
}
} // end namespace
namespace llvm {
std::unique_ptr<ScheduleDAGMutation> createAArch64MacroFusionDAGMutation () {
return createMacroFusionDAGMutation(shouldScheduleAdjacent);
}
} // end namespace llvm