[mlir][ArmSME] Audit arm_sme.tile_store

Makes that the following cases are rejected (as opposed causing the
mlir-opt to crash):

```mlir
arm_sme.tile_store %arg0, %arg1[%c0] : memref<?x4xi8>, vector<[4]x[4]xi32>
arm_sme.tile_store %arg0, %arg1[%c0] : memref<?xi8>, vector<[4]x[4]xi32>
```

Instead, we should be loading from a rank-2 MemRef, using 2 indices,
e.g.:

```mlir
arm_sme.tile_store %arg0, %arg1[%c0, %c0] : memref<?x?xi8>, vector<[4]x[4]xi32>
```

Fixes #118769

Author: banach-space

mlir/include/mlir/Dialect/ArmSME/IR/ArmSMEOps.td

@@ -369,7 +369,7 @@ def TileLoadOp : ArmSME_Op<"tile_load", [
     ```
   }];
   let arguments = (ins
-    Arg<AnyMemRef, "the reference to load from", [MemRead]>:$base,
+    Arg<MemRefRankOf<[AnyType], [2]>, "the reference to load from", [MemRead]>:$base,
     Variadic<Index>:$indices,
     Optional<AnyType>:$padding, Optional<AnyVectorOfNonZeroRank>:$mask,
     ArmSME_TileSliceLayoutAttr:$layout
@@ -443,7 +443,7 @@ def TileStoreOp : ArmSME_Op<"tile_store", [
     ```
   }];
   let arguments = (ins SMETile:$valueToStore,
-    Arg<AnyMemRef, "the reference to store to", [MemWrite]>:$base,
+    Arg<MemRefRankOf<[AnyType], [2]>, "the reference to store to", [MemWrite]>:$base,
     Variadic<Index>:$indices, Optional<AnyVectorOfNonZeroRank>:$mask,
     ArmSME_TileSliceLayoutAttr:$layout
   );

mlir/lib/Conversion/ArmSMEToSCF/ArmSMEToSCF.cpp

@@ -33,20 +33,15 @@ SmallVector<Value, 2> getMemrefIndices(ValueRange indices, unsigned rank,
                                        Value tileSliceIndex,
                                        Value tileSliceNumElts, Location loc,
                                        PatternRewriter &rewriter) {
-  assert((rank == 1 || rank == 2) && "memref has unexpected rank!");
+  assert(rank == 2 && "memref has unexpected rank!");
   SmallVector<Value, 2> outIndices;
 
   auto tileSliceOffset = tileSliceIndex;
-  if (rank == 1)
-    tileSliceOffset =
-        rewriter.create<arith::MulIOp>(loc, tileSliceOffset, tileSliceNumElts);
 
   auto baseIndexPlusTileSliceOffset =
       rewriter.create<arith::AddIOp>(loc, indices[0], tileSliceOffset);
   outIndices.push_back(baseIndexPlusTileSliceOffset);
-
-  if (rank == 2)
-    outIndices.push_back(indices[1]);
+  outIndices.push_back(indices[1]);
 
   return outIndices;
 }
@@ -60,6 +55,10 @@ FailureOr<scf::ForOp> createLoadStoreForOverTileSlices(
         makeLoopBody) {
   PatternRewriter::InsertionGuard guard(rewriter);
 
+  // TODO: This case should be captured and rejected by a verifier.
+  if (memrefIndices.size() != 2)
+    return rewriter.notifyMatchFailure(loc, "invalid number of indices");
+
   auto minTileSlices = rewriter.create<arith::ConstantIndexOp>(
       loc, arm_sme::getSMETileSliceMinNumElts(tileType.getElementType()));
   auto vscale =

mlir/test/Dialect/ArmSME/invalid.mlir

@@ -111,6 +111,15 @@ func.func @arm_sme_tile_load__pad_but_no_mask(%src : memref<?x?xf64>, %pad : f64
   return
 }
 
+// -----
+
+func.func @arm_sme_tile_load__bad_memref_rank(%src : memref<?xf64>, %pad : f64) {
+  %c0 = arith.constant 0 : index
+  // expected-error@+1 {{op operand #0 must be 2D memref of any type values, but got 'memref<?xf64>'}}
+  %tile = arm_sme.tile_load %src[%c0], %pad, : memref<?xf64>, vector<[2]x[2]xf64>
+  return
+}
+
 //===----------------------------------------------------------------------===//
 // arm_sme.load_tile_slice
 //===----------------------------------------------------------------------===//
@@ -138,6 +147,15 @@ func.func @arm_sme_tile_store__bad_mask_type(%tile : vector<[16]x[16]xi8>, %mask
   return
 }
 
+// -----
+
+func.func @arm_sme_tile_store__bad_memref_rank(%tile : vector<[16]x[16]xi8>, %dest : memref<?xi8>) {
+  %c0 = arith.constant 0 : index
+  // expected-error@+1 {{op operand #1 must be 2D memref of any type values, but got 'memref<?xi8>'}}
+  arm_sme.tile_store %tile, %dest[%c0] : memref<?xi8>, vector<[16]x[16]xi8>
+  return
+}
+
 //===----------------------------------------------------------------------===//
 // arm_sme.store_tile_slice
 //===----------------------------------------------------------------------===//