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//===- 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 {
// Fuse CMN, CMP, TST followed by Bcc.
static bool isArithmeticBccPair(const MachineInstr *FirstMI,
const MachineInstr &SecondMI) {
if (SecondMI.getOpcode() == AArch64::Bcc) {
// Assume the 1st instr to be a wildcard if it is unspecified.
if (!FirstMI)
return true;
switch (FirstMI->getOpcode()) {
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 (!AArch64InstrInfo::hasShiftedReg(*FirstMI));
}
}
return false;
}
// Fuse ALU operations followed by CBZ/CBNZ.
static bool isArithmeticCbzPair(const MachineInstr *FirstMI,
const MachineInstr &SecondMI) {
unsigned SecondOpcode = SecondMI.getOpcode();
if (SecondOpcode == AArch64::CBNZW || SecondOpcode == AArch64::CBNZX ||
SecondOpcode == AArch64::CBZW || SecondOpcode == AArch64::CBZX) {
// Assume the 1st instr to be a wildcard if it is unspecified.
if (!FirstMI)
return true;
switch (FirstMI->getOpcode()) {
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 (!AArch64InstrInfo::hasShiftedReg(*FirstMI));
}
}
return false;
}
// Fuse AES crypto encoding or decoding.
static bool isAESPair(const MachineInstr *FirstMI,
const MachineInstr &SecondMI) {
// Assume the 1st instr to be a wildcard if it is unspecified.
unsigned FirstOpcode =
FirstMI ? FirstMI->getOpcode()
: static_cast<unsigned>(AArch64::INSTRUCTION_LIST_END);
unsigned SecondOpcode = SecondMI.getOpcode();
// AES encode.
if ((FirstOpcode == AArch64::INSTRUCTION_LIST_END ||
FirstOpcode == AArch64::AESErr) &&
(SecondOpcode == AArch64::AESMCrr ||
SecondOpcode == AArch64::AESMCrrTied))
return true;
// AES decode.
else if ((FirstOpcode == AArch64::INSTRUCTION_LIST_END ||
FirstOpcode == AArch64::AESDrr) &&
(SecondOpcode == AArch64::AESIMCrr ||
SecondOpcode == AArch64::AESIMCrrTied))
return true;
return false;
}
// Fuse literal generation.
static bool isLiteralsPair(const MachineInstr *FirstMI,
const MachineInstr &SecondMI) {
// Assume the 1st instr to be a wildcard if it is unspecified.
unsigned FirstOpcode =
FirstMI ? FirstMI->getOpcode()
: static_cast<unsigned>(AArch64::INSTRUCTION_LIST_END);
unsigned SecondOpcode = SecondMI.getOpcode();
// PC relative address.
if ((FirstOpcode == AArch64::INSTRUCTION_LIST_END ||
FirstOpcode == AArch64::ADRP) &&
SecondOpcode == AArch64::ADDXri)
return true;
// 32 bit immediate.
else if ((FirstOpcode == AArch64::INSTRUCTION_LIST_END ||
FirstOpcode == AArch64::MOVZWi) &&
(SecondOpcode == AArch64::MOVKWi &&
SecondMI.getOperand(3).getImm() == 16))
return true;
// Lower half of 64 bit immediate.
else if((FirstOpcode == AArch64::INSTRUCTION_LIST_END ||
FirstOpcode == AArch64::MOVZXi) &&
(SecondOpcode == AArch64::MOVKXi &&
SecondMI.getOperand(3).getImm() == 16))
return true;
// Upper half of 64 bit immediate.
else if ((FirstOpcode == AArch64::INSTRUCTION_LIST_END ||
(FirstOpcode == AArch64::MOVKXi &&
FirstMI->getOperand(3).getImm() == 32)) &&
(SecondOpcode == AArch64::MOVKXi &&
SecondMI.getOperand(3).getImm() == 48))
return true;
return false;
}
// Fuse address generation and loads or stores.
static bool isAddressLdStPair(const MachineInstr *FirstMI,
const MachineInstr &SecondMI) {
unsigned SecondOpcode = SecondMI.getOpcode();
switch (SecondOpcode) {
case AArch64::STRBBui:
case AArch64::STRBui:
case AArch64::STRDui:
case AArch64::STRHHui:
case AArch64::STRHui:
case AArch64::STRQui:
case AArch64::STRSui:
case AArch64::STRWui:
case AArch64::STRXui:
case AArch64::LDRBBui:
case AArch64::LDRBui:
case AArch64::LDRDui:
case AArch64::LDRHHui:
case AArch64::LDRHui:
case AArch64::LDRQui:
case AArch64::LDRSui:
case AArch64::LDRWui:
case AArch64::LDRXui:
case AArch64::LDRSBWui:
case AArch64::LDRSBXui:
case AArch64::LDRSHWui:
case AArch64::LDRSHXui:
case AArch64::LDRSWui:
// Assume the 1st instr to be a wildcard if it is unspecified.
if (!FirstMI)
return true;
switch (FirstMI->getOpcode()) {
case AArch64::ADR:
return (SecondMI.getOperand(2).getImm() == 0);
case AArch64::ADRP:
return true;
}
}
return false;
}
// Fuse compare and conditional select.
static bool isCCSelectPair(const MachineInstr *FirstMI,
const MachineInstr &SecondMI) {
unsigned SecondOpcode = SecondMI.getOpcode();
// 32 bits
if (SecondOpcode == AArch64::CSELWr) {
// Assume the 1st instr to be a wildcard if it is unspecified.
if (!FirstMI)
return true;
if (FirstMI->definesRegister(AArch64::WZR))
switch (FirstMI->getOpcode()) {
case AArch64::SUBSWrs:
return (!AArch64InstrInfo::hasShiftedReg(*FirstMI));
case AArch64::SUBSWrx:
return (!AArch64InstrInfo::hasExtendedReg(*FirstMI));
case AArch64::SUBSWrr:
case AArch64::SUBSWri:
return true;
}
}
// 64 bits
else if (SecondOpcode == AArch64::CSELXr) {
// Assume the 1st instr to be a wildcard if it is unspecified.
if (!FirstMI)
return true;
if (FirstMI->definesRegister(AArch64::XZR))
switch (FirstMI->getOpcode()) {
case AArch64::SUBSXrs:
return (!AArch64InstrInfo::hasShiftedReg(*FirstMI));
case AArch64::SUBSXrx:
case AArch64::SUBSXrx64:
return (!AArch64InstrInfo::hasExtendedReg(*FirstMI));
case AArch64::SUBSXrr:
case AArch64::SUBSXri:
return true;
}
}
return false;
}
/// 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 AArch64Subtarget &ST = static_cast<const AArch64Subtarget&>(TSI);
if (ST.hasArithmeticBccFusion() && isArithmeticBccPair(FirstMI, SecondMI))
return true;
if (ST.hasArithmeticCbzFusion() && isArithmeticCbzPair(FirstMI, SecondMI))
return true;
if (ST.hasFuseAES() && isAESPair(FirstMI, SecondMI))
return true;
if (ST.hasFuseLiterals() && isLiteralsPair(FirstMI, SecondMI))
return true;
if (ST.hasFuseAddress() && isAddressLdStPair(FirstMI, SecondMI))
return true;
if (ST.hasFuseCCSelect() && isCCSelectPair(FirstMI, SecondMI))
return true;
return false;
}
} // end namespace
namespace llvm {
std::unique_ptr<ScheduleDAGMutation> createAArch64MacroFusionDAGMutation () {
return createMacroFusionDAGMutation(shouldScheduleAdjacent);
}
} // end namespace llvm
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