================
@@ -4825,6 +4827,72 @@ SDValue AArch64TargetLowering::getPStateSM(SelectionDAG
&DAG, SDValue Chain,
Mask);
}
+SDValue LowerSMELdrStr(SDValue N, SelectionDAG &DAG, bool IsLoad) {
+ // Lower an SME LDR/STR ZA intrinsic to LDR_ZA_PSEUDO or STR_ZA.
+ // If the vector number is an immediate between 0 and 15 inclusive then we
can
+ // put that directly into the immediate field of the instruction. If it's
+ // outside of that range then we modify the base and slice by the greatest
+ // multiple of 15 smaller than that number and put the remainder in the
+ // instruction field. If it's not an immediate then we modify the base and
+ // slice registers by that number and put 0 in the instruction.
+ SDLoc DL(N);
+
+ SDValue TileSlice = N->getOperand(2);
+ SDValue Base = N->getOperand(3);
+ SDValue VecNum = N->getOperand(4);
+ SDValue Remainder = DAG.getTargetConstant(0, DL, MVT::i32);
+
+ // true if the base and slice registers need to me modified
+ bool NeedsAdd = true;
+ if (auto ImmNode = dyn_cast<ConstantSDNode>(VecNum)) {
+ int Imm = ImmNode->getSExtValue();
+ if (Imm >= 0 && Imm <= 15) {
+ Remainder = DAG.getTargetConstant(Imm, DL, MVT::i32);
+ NeedsAdd = false;
+ } else {
+ Remainder = DAG.getTargetConstant(Imm % 15, DL, MVT::i32);
+ NeedsAdd = true;
+ VecNum = DAG.getConstant(Imm - (Imm % 15), DL, MVT::i32);
+ }
+ } else if (VecNum.getOpcode() == ISD::ADD) {
+ // If the vnum is an add, we can fold that add into the instruction if the
+ // operand is an immediate in range
+ if (auto ImmNode = dyn_cast<ConstantSDNode>(VecNum.getOperand(1))) {
+ int Imm = ImmNode->getSExtValue();
+ if (Imm >= 0 && Imm <= 15) {
----------------
SamTebbs33 wrote:
My latest two commits do this, which improves the codegen as well since we
properly fold successive loads/stores with adds of large immediates. See the
test [here](https://media.tenor.com/vYhPH4gA184AAAAC/vroom-car.gif). Thanks for
the idea!
https://github.com/llvm/llvm-project/pull/68565
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