class MachineCopyPropagation : public MachineFunctionPass {
const TargetRegisterInfo *TRI;
BitVector ReservedRegs;
-
+
public:
static char ID; // Pass identification, replacement for typeid
MachineCopyPropagation() : MachineFunctionPass(ID) {
};
}
char MachineCopyPropagation::ID = 0;
+char &llvm::MachineCopyPropagationID = MachineCopyPropagation::ID;
INITIALIZE_PASS(MachineCopyPropagation, "machine-cp",
"Machine Copy Propagation Pass", false, false)
-FunctionPass *llvm::createMachineCopyPropagationPass() {
- return new MachineCopyPropagation();
-}
-
void
MachineCopyPropagation::SourceNoLongerAvailable(unsigned Reg,
DenseMap<unsigned, unsigned> &SrcMap,
// %RSP<def> = COPY %RAX
// CALL
// %RAX<def> = COPY %RSP
- CopyMI->getOperand(1).setIsKill(false);
+
+ // Clear any kills of Def between CopyMI and MI. This extends the
+ // live range.
+ for (MachineBasicBlock::iterator I = CopyMI, E = MI; I != E; ++I)
+ I->clearRegisterKills(Def, TRI);
+
MI->eraseFromParent();
Changed = true;
++NumDeletes;
// Not a copy.
SmallVector<unsigned, 2> Defs;
+ int RegMaskOpNum = -1;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(i);
+ if (MO.isRegMask())
+ RegMaskOpNum = i;
if (!MO.isReg())
continue;
unsigned Reg = MO.getReg();
}
}
+ // The instruction has a register mask operand which means that it clobbers
+ // a large set of registers. It is possible to use the register mask to
+ // prune the available copies, but treat it like a basic block boundary for
+ // now.
+ if (RegMaskOpNum >= 0) {
+ // Erase any MaybeDeadCopies whose destination register is clobbered.
+ const MachineOperand &MaskMO = MI->getOperand(RegMaskOpNum);
+ for (SmallSetVector<MachineInstr*, 8>::iterator
+ DI = MaybeDeadCopies.begin(), DE = MaybeDeadCopies.end();
+ DI != DE; ++DI) {
+ unsigned Reg = (*DI)->getOperand(0).getReg();
+ if (ReservedRegs.test(Reg) || !MaskMO.clobbersPhysReg(Reg))
+ continue;
+ (*DI)->eraseFromParent();
+ Changed = true;
+ ++NumDeletes;
+ }
+
+ // Clear all data structures as if we were beginning a new basic block.
+ MaybeDeadCopies.clear();
+ AvailCopyMap.clear();
+ CopyMap.clear();
+ SrcMap.clear();
+ continue;
+ }
+
for (unsigned i = 0, e = Defs.size(); i != e; ++i) {
unsigned Reg = Defs[i];