// fold (mul c1, c2) -> c1*c2
if (N0C && N1C)
- return DAG.getConstant(N0C->getValue() * N1C->getValue(),
- N->getValueType(0));
+ return DAG.getConstant(N0C->getValue() * N1C->getValue(), VT);
// canonicalize constant to RHS
if (N0C && !N1C)
return DAG.getNode(ISD::MUL, VT, N1, N0);
return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), N0);
// fold (mul x, (1 << c)) -> x << c
if (N1C && isPowerOf2_64(N1C->getValue()))
- return DAG.getNode(ISD::SHL, N->getValueType(0), N0,
+ return DAG.getNode(ISD::SHL, VT, N0,
DAG.getConstant(Log2_64(N1C->getValue()),
TLI.getShiftAmountTy()));
+ // fold (mul x, -(1 << c)) -> -(x << c) or (-x) << c
+ if (N1C && isPowerOf2_64(-N1C->getSignExtended())) {
+ // FIXME: If the input is something that is easily negated (e.g. a
+ // single-use add), we should put the negate there.
+ return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT),
+ DAG.getNode(ISD::SHL, VT, N0,
+ DAG.getConstant(Log2_64(-N1C->getSignExtended()),
+ TLI.getShiftAmountTy())));
+ }
+
+
// fold (mul (mul x, c1), c2) -> (mul x, c1*c2)
if (N1C && N0.getOpcode() == ISD::MUL) {
ConstantSDNode *N00C = dyn_cast<ConstantSDNode>(N0.getOperand(0));