HexagonNewValueJump.cpp [plain text]
#include "llvm/PassSupport.h"
#include "Hexagon.h"
#include "HexagonInstrInfo.h"
#include "HexagonMachineFunctionInfo.h"
#include "HexagonRegisterInfo.h"
#include "HexagonSubtarget.h"
#include "HexagonTargetMachine.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/LiveVariables.h"
#include "llvm/CodeGen/MachineFunctionAnalysis.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/ScheduleDAGInstrs.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include <map>
using namespace llvm;
#define DEBUG_TYPE "hexagon-nvj"
STATISTIC(NumNVJGenerated, "Number of New Value Jump Instructions created");
static cl::opt<int>
DbgNVJCount("nvj-count", cl::init(-1), cl::Hidden, cl::desc(
"Maximum number of predicated jumps to be converted to New Value Jump"));
static cl::opt<bool> DisableNewValueJumps("disable-nvjump", cl::Hidden,
cl::ZeroOrMore, cl::init(false),
cl::desc("Disable New Value Jumps"));
namespace llvm {
void initializeHexagonNewValueJumpPass(PassRegistry&);
}
namespace {
struct HexagonNewValueJump : public MachineFunctionPass {
const HexagonInstrInfo *QII;
const HexagonRegisterInfo *QRI;
public:
static char ID;
HexagonNewValueJump() : MachineFunctionPass(ID) {
initializeHexagonNewValueJumpPass(*PassRegistry::getPassRegistry());
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<MachineBranchProbabilityInfo>();
MachineFunctionPass::getAnalysisUsage(AU);
}
const char *getPassName() const override {
return "Hexagon NewValueJump";
}
bool runOnMachineFunction(MachineFunction &Fn) override;
private:
const MachineBranchProbabilityInfo *MBPI;
};
}
char HexagonNewValueJump::ID = 0;
INITIALIZE_PASS_BEGIN(HexagonNewValueJump, "hexagon-nvj",
"Hexagon NewValueJump", false, false)
INITIALIZE_PASS_DEPENDENCY(MachineBranchProbabilityInfo)
INITIALIZE_PASS_END(HexagonNewValueJump, "hexagon-nvj",
"Hexagon NewValueJump", false, false)
static bool canBeFeederToNewValueJump(const HexagonInstrInfo *QII,
const TargetRegisterInfo *TRI,
MachineBasicBlock::iterator II,
MachineBasicBlock::iterator end,
MachineBasicBlock::iterator skip,
MachineFunction &MF) {
if (QII->isPredicated(II))
return false;
if (II->getOpcode() == TargetOpcode::KILL)
return false;
for (unsigned i = 0; i < II->getNumOperands(); ++i) {
if (II->getOperand(i).isReg() &&
(II->getOperand(i).isUse() || II->getOperand(i).isDef())) {
MachineBasicBlock::iterator localII = II;
++localII;
unsigned Reg = II->getOperand(i).getReg();
for (MachineBasicBlock::iterator localBegin = localII;
localBegin != end; ++localBegin) {
if (localBegin == skip ) continue;
if (localBegin->modifiesRegister(Reg, TRI) ||
localBegin->readsRegister(Reg, TRI))
return false;
}
}
}
return true;
}
static bool commonChecksToProhibitNewValueJump(bool afterRA,
MachineBasicBlock::iterator MII) {
if (MII->getDesc().mayStore())
return false;
if (MII->getOpcode() == Hexagon::J2_call)
return false;
if (!afterRA) {
if (MII->getOpcode() == TargetOpcode::KILL ||
MII->getOpcode() == TargetOpcode::PHI ||
MII->getOpcode() == TargetOpcode::COPY)
return false;
if (MII->getOpcode() == Hexagon::TFR_condset_ii ||
MII->getOpcode() == Hexagon::TFR_condset_ri ||
MII->getOpcode() == Hexagon::TFR_condset_ir ||
MII->getOpcode() == Hexagon::LDriw_pred ||
MII->getOpcode() == Hexagon::STriw_pred)
return false;
}
return true;
}
static bool canCompareBeNewValueJump(const HexagonInstrInfo *QII,
const TargetRegisterInfo *TRI,
MachineBasicBlock::iterator II,
unsigned pReg,
bool secondReg,
bool optLocation,
MachineBasicBlock::iterator end,
MachineFunction &MF) {
MachineInstr *MI = II;
if (!secondReg) {
int64_t v = MI->getOperand(2).getImm();
if (!(isUInt<5>(v) ||
((MI->getOpcode() == Hexagon::C2_cmpeqi ||
MI->getOpcode() == Hexagon::C2_cmpgti) &&
(v == -1))))
return false;
}
unsigned cmpReg1, cmpOp2 = 0; cmpReg1 = MI->getOperand(1).getReg();
if (secondReg) {
cmpOp2 = MI->getOperand(2).getReg();
MachineRegisterInfo &MRI = MF.getRegInfo();
if (secondReg && !TargetRegisterInfo::isPhysicalRegister(cmpOp2)) {
MachineInstr *def = MRI.getVRegDef(cmpOp2);
if (def->getOpcode() == TargetOpcode::COPY)
return false;
}
}
++II ;
for (MachineBasicBlock::iterator localII = II; localII != end;
++localII) {
if (!commonChecksToProhibitNewValueJump(optLocation, localII))
return false;
if (localII->modifiesRegister(pReg, TRI) ||
localII->readsRegister(pReg, TRI))
return false;
if (localII->modifiesRegister(cmpReg1, TRI) ||
(secondReg && localII->modifiesRegister(cmpOp2, TRI)))
return false;
}
return true;
}
static unsigned getNewValueJumpOpcode(MachineInstr *MI, int reg,
bool secondRegNewified,
MachineBasicBlock *jmpTarget,
const MachineBranchProbabilityInfo
*MBPI) {
bool taken = false;
MachineBasicBlock *Src = MI->getParent();
const BranchProbability Prediction =
MBPI->getEdgeProbability(Src, jmpTarget);
if (Prediction >= BranchProbability(1,2))
taken = true;
switch (MI->getOpcode()) {
case Hexagon::C2_cmpeq:
return taken ? Hexagon::J4_cmpeq_t_jumpnv_t
: Hexagon::J4_cmpeq_t_jumpnv_nt;
case Hexagon::C2_cmpeqi: {
if (reg >= 0)
return taken ? Hexagon::J4_cmpeqi_t_jumpnv_t
: Hexagon::J4_cmpeqi_t_jumpnv_nt;
else
return taken ? Hexagon::J4_cmpeqn1_t_jumpnv_t
: Hexagon::J4_cmpeqn1_t_jumpnv_nt;
}
case Hexagon::C2_cmpgt: {
if (secondRegNewified)
return taken ? Hexagon::J4_cmplt_t_jumpnv_t
: Hexagon::J4_cmplt_t_jumpnv_nt;
else
return taken ? Hexagon::J4_cmpgt_t_jumpnv_t
: Hexagon::J4_cmpgt_t_jumpnv_nt;
}
case Hexagon::C2_cmpgti: {
if (reg >= 0)
return taken ? Hexagon::J4_cmpgti_t_jumpnv_t
: Hexagon::J4_cmpgti_t_jumpnv_nt;
else
return taken ? Hexagon::J4_cmpgtn1_t_jumpnv_t
: Hexagon::J4_cmpgtn1_t_jumpnv_nt;
}
case Hexagon::C2_cmpgtu: {
if (secondRegNewified)
return taken ? Hexagon::J4_cmpltu_t_jumpnv_t
: Hexagon::J4_cmpltu_t_jumpnv_nt;
else
return taken ? Hexagon::J4_cmpgtu_t_jumpnv_t
: Hexagon::J4_cmpgtu_t_jumpnv_nt;
}
case Hexagon::C2_cmpgtui:
return taken ? Hexagon::J4_cmpgtui_t_jumpnv_t
: Hexagon::J4_cmpgtui_t_jumpnv_nt;
default:
llvm_unreachable("Could not find matching New Value Jump instruction.");
}
return 0;
}
bool HexagonNewValueJump::runOnMachineFunction(MachineFunction &MF) {
DEBUG(dbgs() << "********** Hexagon New Value Jump **********\n"
<< "********** Function: "
<< MF.getName() << "\n");
QII = static_cast<const HexagonInstrInfo *>(MF.getSubtarget().getInstrInfo());
QRI = static_cast<const HexagonRegisterInfo *>(
MF.getSubtarget().getRegisterInfo());
MBPI = &getAnalysis<MachineBranchProbabilityInfo>();
if (DisableNewValueJumps) {
return false;
}
int nvjCount = DbgNVJCount;
int nvjGenerated = 0;
for (MachineFunction::iterator MBBb = MF.begin(), MBBe = MF.end();
MBBb != MBBe; ++MBBb) {
MachineBasicBlock* MBB = MBBb;
DEBUG(dbgs() << "** dumping bb ** "
<< MBB->getNumber() << "\n");
DEBUG(MBB->dump());
DEBUG(dbgs() << "\n" << "********** dumping instr bottom up **********\n");
bool foundJump = false;
bool foundCompare = false;
bool invertPredicate = false;
unsigned predReg = 0; unsigned cmpReg1 = 0;
int cmpOp2 = 0;
bool MO1IsKill = false;
bool MO2IsKill = false;
MachineBasicBlock::iterator jmpPos;
MachineBasicBlock::iterator cmpPos;
MachineInstr *cmpInstr = nullptr, *jmpInstr = nullptr;
MachineBasicBlock *jmpTarget = nullptr;
bool afterRA = false;
bool isSecondOpReg = false;
bool isSecondOpNewified = false;
for (MachineBasicBlock::iterator MII = MBB->end(), E = MBB->begin();
MII != E;) {
MachineInstr *MI = --MII;
if (MI->isDebugValue()) {
continue;
}
if ((nvjCount == 0) || (nvjCount > -1 && nvjCount <= nvjGenerated))
break;
DEBUG(dbgs() << "Instr: "; MI->dump(); dbgs() << "\n");
if (!foundJump &&
(MI->getOpcode() == Hexagon::J2_jumpt ||
MI->getOpcode() == Hexagon::J2_jumpf ||
MI->getOpcode() == Hexagon::J2_jumptnewpt ||
MI->getOpcode() == Hexagon::J2_jumptnew ||
MI->getOpcode() == Hexagon::J2_jumpfnewpt ||
MI->getOpcode() == Hexagon::J2_jumpfnew)) {
jmpPos = MII;
jmpInstr = MI;
predReg = MI->getOperand(0).getReg();
afterRA = TargetRegisterInfo::isPhysicalRegister(predReg);
bool predLive = false;
for (MachineBasicBlock::const_succ_iterator SI = MBB->succ_begin(),
SIE = MBB->succ_end(); SI != SIE; ++SI) {
MachineBasicBlock* succMBB = *SI;
if (succMBB->isLiveIn(predReg)) {
predLive = true;
}
}
if (predLive)
break;
jmpTarget = MI->getOperand(1).getMBB();
foundJump = true;
if (MI->getOpcode() == Hexagon::J2_jumpf ||
MI->getOpcode() == Hexagon::J2_jumpfnewpt ||
MI->getOpcode() == Hexagon::J2_jumpfnew) {
invertPredicate = true;
}
continue;
}
if (foundJump && MI->getNumOperands() == 0)
break;
if (foundJump &&
!foundCompare &&
MI->getOperand(0).isReg() &&
MI->getOperand(0).getReg() == predReg) {
if (QII->isNewValueJumpCandidate(MI)) {
assert((MI->getDesc().isCompare()) &&
"Only compare instruction can be collapsed into New Value Jump");
isSecondOpReg = MI->getOperand(2).isReg();
if (!canCompareBeNewValueJump(QII, QRI, MII, predReg, isSecondOpReg,
afterRA, jmpPos, MF))
break;
cmpInstr = MI;
cmpPos = MII;
foundCompare = true;
cmpReg1 = MI->getOperand(1).getReg();
if (MI->getOperand(1).isKill())
MO1IsKill = true;
if (isSecondOpReg) {
cmpOp2 = MI->getOperand(2).getReg();
if (MI->getOperand(2).isKill())
MO2IsKill = true;
} else
cmpOp2 = MI->getOperand(2).getImm();
continue;
}
}
if (foundCompare && foundJump) {
if (!commonChecksToProhibitNewValueJump(afterRA, MII))
break;
bool foundFeeder = false;
MachineBasicBlock::iterator feederPos = MII;
if (MI->getOperand(0).isReg() &&
MI->getOperand(0).isDef() &&
(MI->getOperand(0).getReg() == cmpReg1 ||
(isSecondOpReg &&
MI->getOperand(0).getReg() == (unsigned) cmpOp2))) {
unsigned feederReg = MI->getOperand(0).getReg();
if (feederReg == cmpReg1) {
if (!canBeFeederToNewValueJump(QII, QRI, MII, jmpPos, cmpPos, MF)) {
if (!isSecondOpReg)
break;
else
continue;
} else
foundFeeder = true;
}
if (!foundFeeder &&
isSecondOpReg &&
feederReg == (unsigned) cmpOp2)
if (!canBeFeederToNewValueJump(QII, QRI, MII, jmpPos, cmpPos, MF))
break;
if (isSecondOpReg) {
if (cmpInstr->getOpcode() == Hexagon::C2_cmpeq &&
feederReg == (unsigned) cmpOp2) {
unsigned tmp = cmpReg1;
bool tmpIsKill = MO1IsKill;
cmpReg1 = cmpOp2;
MO1IsKill = MO2IsKill;
cmpOp2 = tmp;
MO2IsKill = tmpIsKill;
}
if (feederReg == (unsigned)cmpOp2)
isSecondOpNewified = true;
}
bool updatedIsKill = false;
for (unsigned i = 0; i < MI->getNumOperands(); i++) {
MachineOperand &MO = MI->getOperand(i);
if (MO.isReg() && MO.isUse()) {
unsigned feederReg = MO.getReg();
for (MachineBasicBlock::iterator localII = feederPos,
end = jmpPos; localII != end; localII++) {
MachineInstr *localMI = localII;
for (unsigned j = 0; j < localMI->getNumOperands(); j++) {
MachineOperand &localMO = localMI->getOperand(j);
if (localMO.isReg() && localMO.isUse() &&
localMO.isKill() && feederReg == localMO.getReg()) {
localMO.setIsKill(false);
MO.setIsKill();
updatedIsKill = true;
break;
}
}
if (updatedIsKill) break;
}
}
if (updatedIsKill) break;
}
MBB->splice(jmpPos, MI->getParent(), MI);
MBB->splice(jmpPos, MI->getParent(), cmpInstr);
DebugLoc dl = MI->getDebugLoc();
MachineInstr *NewMI;
assert((QII->isNewValueJumpCandidate(cmpInstr)) &&
"This compare is not a New Value Jump candidate.");
unsigned opc = getNewValueJumpOpcode(cmpInstr, cmpOp2,
isSecondOpNewified,
jmpTarget, MBPI);
if (invertPredicate)
opc = QII->getInvertedPredicatedOpcode(opc);
if (isSecondOpReg)
NewMI = BuildMI(*MBB, jmpPos, dl,
QII->get(opc))
.addReg(cmpReg1, getKillRegState(MO1IsKill))
.addReg(cmpOp2, getKillRegState(MO2IsKill))
.addMBB(jmpTarget);
else if ((cmpInstr->getOpcode() == Hexagon::C2_cmpeqi ||
cmpInstr->getOpcode() == Hexagon::C2_cmpgti) &&
cmpOp2 == -1 )
NewMI = BuildMI(*MBB, jmpPos, dl,
QII->get(opc))
.addReg(cmpReg1, getKillRegState(MO1IsKill))
.addMBB(jmpTarget);
else
NewMI = BuildMI(*MBB, jmpPos, dl,
QII->get(opc))
.addReg(cmpReg1, getKillRegState(MO1IsKill))
.addImm(cmpOp2)
.addMBB(jmpTarget);
assert(NewMI && "New Value Jump Instruction Not created!");
(void)NewMI;
if (cmpInstr->getOperand(0).isReg() &&
cmpInstr->getOperand(0).isKill())
cmpInstr->getOperand(0).setIsKill(false);
if (cmpInstr->getOperand(1).isReg() &&
cmpInstr->getOperand(1).isKill())
cmpInstr->getOperand(1).setIsKill(false);
cmpInstr->eraseFromParent();
jmpInstr->eraseFromParent();
++nvjGenerated;
++NumNVJGenerated;
break;
}
}
}
}
return true;
}
FunctionPass *llvm::createHexagonNewValueJump() {
return new HexagonNewValueJump();
}