+ // fold (shl (sr[la] exact X, C1), C2) -> (shl X, (C2-C1)) if C1 <= C2
+ // fold (shl (sr[la] exact X, C1), C2) -> (sr[la] X, (C2-C1)) if C1 > C2
+ if (N1C && (N0.getOpcode() == ISD::SRL || N0.getOpcode() == ISD::SRA) &&
+ cast<BinaryWithFlagsSDNode>(N0)->Flags.hasExact()) {
+ if (ConstantSDNode *N0C1 = isConstOrConstSplat(N0.getOperand(1))) {
+ uint64_t C1 = N0C1->getZExtValue();
+ uint64_t C2 = N1C->getZExtValue();
+ SDLoc DL(N);
+ if (C1 <= C2)
+ return DAG.getNode(ISD::SHL, DL, VT, N0.getOperand(0),
+ DAG.getConstant(C2 - C1, DL, N1.getValueType()));
+ return DAG.getNode(N0.getOpcode(), DL, VT, N0.getOperand(0),
+ DAG.getConstant(C1 - C2, DL, N1.getValueType()));
+ }
+ }
+