const TargetInstrInfo &TII = *TM.getInstrInfo();
const TargetRegisterInfo &TRI = *TM.getRegisterInfo();
+ // Remat clients assume operand 0 is the defined register.
+ if (!MI->getNumOperands() || !MI->getOperand(0).isReg())
+ return false;
+ unsigned DefReg = MI->getOperand(0).getReg();
+
// A sub-register definition can only be rematerialized if the instruction
// doesn't read the other parts of the register. Otherwise it is really a
// read-modify-write operation on the full virtual register which cannot be
// moved safely.
- unsigned Reg = MI->getOperand(0).getReg();
- if (TargetRegisterInfo::isVirtualRegister(Reg) &&
- MI->getOperand(0).getSubReg() && MI->readsVirtualRegister(Reg))
+ if (TargetRegisterInfo::isVirtualRegister(DefReg) &&
+ MI->getOperand(0).getSubReg() && MI->readsVirtualRegister(DefReg))
return false;
// A load from a fixed stack slot can be rematerialized. This may be
continue;
}
- // Only allow one virtual-register def, and that in the first operand.
- if (MO.isDef() != (i == 0))
+ // Only allow one virtual-register def. There may be multiple defs of the
+ // same virtual register, though.
+ if (MO.isDef() && Reg != DefReg)
return false;
// Don't allow any virtual-register uses. Rematting an instruction with