bool ARMDAGToDAGISel::SelectT2AddrModeImm8(SDValue Op, SDValue N,
SDValue &Base, SDValue &OffImm) {
- if (N.getOpcode() == ISD::ADD) {
+ if ((N.getOpcode() == ISD::ADD) || (N.getOpcode() == ISD::SUB)) {
if (ConstantSDNode *RHS = dyn_cast<ConstantSDNode>(N.getOperand(1))) {
- int RHSC = (int)RHS->getZExtValue();
- if (RHSC < 0 && RHSC > -0x100) { // 8 bits.
+ int RHSC = (int)RHS->getSExtValue();
+ if (N.getOpcode() == ISD::SUB)
+ RHSC = -RHSC;
+
+ if ((RHSC >= -255) && (RHSC <= 255)) { // sign + 8 bits.
Base = N.getOperand(0);
OffImm = CurDAG->getTargetConstant(RHSC, MVT::i32);
return true;
}
- }
- } else if (N.getOpcode() == ISD::SUB) {
- if (ConstantSDNode *RHS = dyn_cast<ConstantSDNode>(N.getOperand(1))) {
- int RHSC = (int)RHS->getZExtValue();
- if (RHSC >= 0 && RHSC < 0x100) { // 8 bits.
- Base = N.getOperand(0);
- OffImm = CurDAG->getTargetConstant(-RHSC, MVT::i32);
- return true;
- }
+ } else if (N.getOpcode() == ISD::SUB) {
+ Base = N;
+ OffImm = CurDAG->getTargetConstant(0, MVT::i32);
+ return true;
}
}
return true;
}
+ // Thumb2 does not support (R - R) or (R - (R << [1,2,3])).
+ if (N.getOpcode() != ISD::ADD)
+ return false;
+
// Look for (R + R) or (R + (R << [1,2,3])).
unsigned ShAmt = 0;
Base = N.getOperand(0);
ShOpcVal = ARM_AM::no_shift;
}
} else if (SelectT2AddrModeImm12(Op, N, Base, ShImm) ||
- SelectT2AddrModeImm8 (Op, N, Base, ShImm))
+ SelectT2AddrModeImm8 (Op, N, Base, ShImm)) {
// Don't match if it's possible to match to one of the r +/- imm cases.
return false;
+ }
ShImm = CurDAG->getTargetConstant(ShAmt, MVT::i32);