+/// isShuffleMaskLegal - Targets can use this to indicate that they only
+/// support *some* VECTOR_SHUFFLE operations, those with specific masks.
+/// By default, if a target supports the VECTOR_SHUFFLE node, all mask values
+/// are assumed to be legal.
+bool
+ARMTargetLowering::isShuffleMaskLegal(const SmallVectorImpl<int> &M,
+ EVT VT) const {
+ if (VT.getVectorNumElements() == 4 &&
+ (VT.is128BitVector() || VT.is64BitVector())) {
+ unsigned PFIndexes[4];
+ for (unsigned i = 0; i != 4; ++i) {
+ if (M[i] < 0)
+ PFIndexes[i] = 8;
+ else
+ PFIndexes[i] = M[i];
+ }
+
+ // Compute the index in the perfect shuffle table.
+ unsigned PFTableIndex =
+ PFIndexes[0]*9*9*9+PFIndexes[1]*9*9+PFIndexes[2]*9+PFIndexes[3];
+ unsigned PFEntry = PerfectShuffleTable[PFTableIndex];
+ unsigned Cost = (PFEntry >> 30);
+
+ if (Cost <= 4)
+ return true;
+ }
+
+ bool ReverseVEXT;
+ unsigned Imm, WhichResult;
+
+ return (ShuffleVectorSDNode::isSplatMask(&M[0], VT) ||
+ isVREVMask(M, VT, 64) ||
+ isVREVMask(M, VT, 32) ||
+ isVREVMask(M, VT, 16) ||
+ isVEXTMask(M, VT, ReverseVEXT, Imm) ||
+ isVTRNMask(M, VT, WhichResult) ||
+ isVUZPMask(M, VT, WhichResult) ||
+ isVZIPMask(M, VT, WhichResult));
+}
+
+/// GeneratePerfectShuffle - Given an entry in the perfect-shuffle table, emit
+/// the specified operations to build the shuffle.
+static SDValue GeneratePerfectShuffle(unsigned PFEntry, SDValue LHS,
+ SDValue RHS, SelectionDAG &DAG,
+ DebugLoc dl) {
+ unsigned OpNum = (PFEntry >> 26) & 0x0F;
+ unsigned LHSID = (PFEntry >> 13) & ((1 << 13)-1);
+ unsigned RHSID = (PFEntry >> 0) & ((1 << 13)-1);
+
+ enum {
+ OP_COPY = 0, // Copy, used for things like <u,u,u,3> to say it is <0,1,2,3>
+ OP_VREV,
+ OP_VDUP0,
+ OP_VDUP1,
+ OP_VDUP2,
+ OP_VDUP3,
+ OP_VEXT1,
+ OP_VEXT2,
+ OP_VEXT3,
+ OP_VUZPL, // VUZP, left result
+ OP_VUZPR, // VUZP, right result
+ OP_VZIPL, // VZIP, left result
+ OP_VZIPR, // VZIP, right result
+ OP_VTRNL, // VTRN, left result
+ OP_VTRNR // VTRN, right result
+ };
+
+ if (OpNum == OP_COPY) {
+ if (LHSID == (1*9+2)*9+3) return LHS;
+ assert(LHSID == ((4*9+5)*9+6)*9+7 && "Illegal OP_COPY!");
+ return RHS;
+ }
+
+ SDValue OpLHS, OpRHS;
+ OpLHS = GeneratePerfectShuffle(PerfectShuffleTable[LHSID], LHS, RHS, DAG, dl);
+ OpRHS = GeneratePerfectShuffle(PerfectShuffleTable[RHSID], LHS, RHS, DAG, dl);
+ EVT VT = OpLHS.getValueType();
+
+ switch (OpNum) {
+ default: llvm_unreachable("Unknown shuffle opcode!");
+ case OP_VREV:
+ return DAG.getNode(ARMISD::VREV64, dl, VT, OpLHS);
+ case OP_VDUP0:
+ case OP_VDUP1:
+ case OP_VDUP2:
+ case OP_VDUP3:
+ return DAG.getNode(ARMISD::VDUPLANE, dl, VT,
+ OpLHS, DAG.getConstant(OpNum-OP_VDUP0, MVT::i32));
+ case OP_VEXT1:
+ case OP_VEXT2:
+ case OP_VEXT3:
+ return DAG.getNode(ARMISD::VEXT, dl, VT,
+ OpLHS, OpRHS,
+ DAG.getConstant(OpNum-OP_VEXT1+1, MVT::i32));
+ case OP_VUZPL:
+ case OP_VUZPR:
+ return DAG.getNode(ARMISD::VUZP, dl, DAG.getVTList(VT, VT),
+ OpLHS, OpRHS).getValue(OpNum-OP_VUZPL);
+ case OP_VZIPL:
+ case OP_VZIPR:
+ return DAG.getNode(ARMISD::VZIP, dl, DAG.getVTList(VT, VT),
+ OpLHS, OpRHS).getValue(OpNum-OP_VZIPL);
+ case OP_VTRNL:
+ case OP_VTRNR:
+ return DAG.getNode(ARMISD::VTRN, dl, DAG.getVTList(VT, VT),
+ OpLHS, OpRHS).getValue(OpNum-OP_VTRNL);
+ }