+ // 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;
+ }
+