/// finalizeBundle - Same functionality as the previous finalizeBundle except
/// the last instruction in the bundle is not provided as an input. This is
/// used in cases where bundles are pre-determined by marking instructions
/// with 'InsideBundle' marker. It returns the MBB instruction iterator that
/// points to the end of the bundle.
MachineBasicBlock::instr_iterator
llvm::finalizeBundle(MachineBasicBlock &MBB,
MachineBasicBlock::instr_iterator FirstMI) {
MachineBasicBlock::instr_iterator E = MBB.instr_end();
MachineBasicBlock::instr_iterator LastMI = std::next(FirstMI);
while (LastMI != E && LastMI->isInsideBundle())
++LastMI;
finalizeBundle(MBB, FirstMI, LastMI);
return LastMI;
}
MachineInstr *MachineBasicBlock::remove(MachineInstr *I) {
if (I->isBundle()) {
MachineBasicBlock::instr_iterator MII = I; ++MII;
while (MII != end() && MII->isInsideBundle()) {
MachineInstr *MI = &*MII++;
Insts.remove(MI);
}
}
return Insts.remove(I);
}
/// finalizeBundles - Finalize instruction bundles in the specified
/// MachineFunction. Return true if any bundles are finalized.
bool llvm::finalizeBundles(MachineFunction &MF) {
bool Changed = false;
for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
MachineBasicBlock &MBB = *I;
MachineBasicBlock::instr_iterator MII = MBB.instr_begin();
MachineBasicBlock::instr_iterator MIE = MBB.instr_end();
if (MII == MIE)
continue;
assert(!MII->isInsideBundle() &&
"First instr cannot be inside bundle before finalization!");
for (++MII; MII != MIE; ) {
if (!MII->isInsideBundle())
++MII;
else {
MII = finalizeBundle(MBB, std::prev(MII));
Changed = true;
}
}
}
return Changed;
}
bool Thumb2SizeReduce::ReduceMBB(MachineBasicBlock &MBB) {
bool Modified = false;
// Yes, CPSR could be livein.
bool LiveCPSR = MBB.isLiveIn(ARM::CPSR);
MachineInstr *CPSRDef = 0;
MachineInstr *BundleMI = 0;
// If this BB loops back to itself, conservatively avoid narrowing the
// first instruction that does partial flag update.
bool IsSelfLoop = MBB.isSuccessor(&MBB);
MachineBasicBlock::instr_iterator MII = MBB.instr_begin(), E = MBB.instr_end();
MachineBasicBlock::instr_iterator NextMII;
for (; MII != E; MII = NextMII) {
NextMII = llvm::next(MII);
MachineInstr *MI = &*MII;
if (MI->isBundle()) {
BundleMI = MI;
continue;
}
LiveCPSR = UpdateCPSRUse(*MI, LiveCPSR);
unsigned Opcode = MI->getOpcode();
DenseMap<unsigned, unsigned>::iterator OPI = ReduceOpcodeMap.find(Opcode);
if (OPI != ReduceOpcodeMap.end()) {
const ReduceEntry &Entry = ReduceTable[OPI->second];
// Ignore "special" cases for now.
if (Entry.Special) {
if (ReduceSpecial(MBB, MI, Entry, LiveCPSR, CPSRDef, IsSelfLoop)) {
Modified = true;
MachineBasicBlock::instr_iterator I = prior(NextMII);
MI = &*I;
}
goto ProcessNext;
}
// Try to transform to a 16-bit two-address instruction.
if (Entry.NarrowOpc2 &&
ReduceTo2Addr(MBB, MI, Entry, LiveCPSR, CPSRDef, IsSelfLoop)) {
Modified = true;
MachineBasicBlock::instr_iterator I = prior(NextMII);
MI = &*I;
goto ProcessNext;
}
// Try to transform to a 16-bit non-two-address instruction.
if (Entry.NarrowOpc1 &&
ReduceToNarrow(MBB, MI, Entry, LiveCPSR, CPSRDef, IsSelfLoop)) {
Modified = true;
MachineBasicBlock::instr_iterator I = prior(NextMII);
MI = &*I;
}
}
ProcessNext:
if (NextMII != E && MI->isInsideBundle() && !NextMII->isInsideBundle()) {
// FIXME: Since post-ra scheduler operates on bundles, the CPSR kill
// marker is only on the BUNDLE instruction. Process the BUNDLE
// instruction as we finish with the bundled instruction to work around
// the inconsistency.
if (BundleMI->killsRegister(ARM::CPSR))
LiveCPSR = false;
MachineOperand *MO = BundleMI->findRegisterDefOperand(ARM::CPSR);
if (MO && !MO->isDead())
LiveCPSR = true;
}
bool DefCPSR = false;
LiveCPSR = UpdateCPSRDef(*MI, LiveCPSR, DefCPSR);
if (MI->isCall()) {
// Calls don't really set CPSR.
CPSRDef = 0;
IsSelfLoop = false;
} else if (DefCPSR) {
// This is the last CPSR defining instruction.
CPSRDef = MI;
IsSelfLoop = false;
}
}
return Modified;
}
