[mlir] Vectorize unpack op given no vector sizes

Enables vectorization of unpack op in the case of unknown vector size.
The vector sizes are determined by the result shape.

Author: pashu123

mlir/lib/Dialect/Linalg/Transforms/Vectorization.cpp

@@ -1597,6 +1597,16 @@ vectorizeAsTensorUnpackOp(RewriterBase &rewriter, tensor::UnPackOp unpackOp,
 
   RankedTensorType unpackTensorType = unpackOp.getSourceType();
 
+  // If the input vector sizes are not provided, then the vector sizes are
+  // determined by the result tensor shape. In case the vector sizes aren't
+  // provided, we update the inBounds attribute instead of masking.
+  bool doMasking = true;
+  if (inputVectorSizes.empty()) {
+    ArrayRef<int64_t> resultTensorShape = unpackOp.getDestType().getShape();
+    inputVectorSizes = resultTensorShape.take_front(unpackOp.getSourceRank());
+    doMasking = false;
+  }
+
   ArrayRef<int64_t> innerDimPos = unpackOp.getInnerDimsPos();
   ArrayRef<int64_t> innerTiles = unpackOp.getStaticInnerTiles();
 
@@ -1651,7 +1661,8 @@ vectorizeAsTensorUnpackOp(RewriterBase &rewriter, tensor::UnPackOp unpackOp,
   // to shape of source, then a mask is necessary.
   Value readResult = createReadOrMaskedRead(
       rewriter, loc, unpackOp.getSource(),
-      ArrayRef<int64_t>(readMaskShape.begin(), readMaskShape.end()), padValue);
+      ArrayRef<int64_t>(readMaskShape.begin(), readMaskShape.end()), padValue,
+      doMasking);
 
   PackingMetadata packMetadata;
   SmallVector<int64_t> lastDimToInsertPosPerm =
@@ -1827,8 +1838,14 @@ vectorizeUnPackOpPrecondition(tensor::UnPackOp unpackOp,
     LDBG("Inner-tiles must be constant: " << unpackOp << "\n");
     return failure();
   }
-  llvm::ArrayRef<int64_t> resultShape = unpackOp.getDestType().getShape();
-  if (!inputVectorSizes.empty() &&
+  ArrayRef<int64_t> resultShape = unpackOp.getDestType().getShape();
+  bool satisfyEmptyCond = true;
+  if (inputVectorSizes.empty()) {
+    if (!unpackOp.getDestType().hasStaticShape() ||
+        !unpackOp.getSourceType().hasStaticShape())
+      satisfyEmptyCond = false;
+  }
+  if (!satisfyEmptyCond &&
       failed(isValidMaskedInputVector(resultShape, inputVectorSizes)))
     return failure();
 

mlir/test/Dialect/Linalg/vectorization.mlir

@@ -985,3 +985,26 @@ module attributes {transform.with_named_sequence} {
     transform.yield
   }
 }
+
+  // -----
+
+func.func @test_vectorize_unpack_no_vector_sizes(%source: tensor<8x8x32x16xf32>, %dest: tensor<256x128xf32>) -> tensor<256x128xf32> {
+  // CHECK: %[[CST:.*]] = arith.constant 0.000000e+00 : f32
+  // CHECK: %[[C0:.*]] = arith.constant 0 : index
+  // CHECK: %[[READ:.*]] = vector.transfer_read {{.*}} : tensor<8x8x32x16xf32>, vector<8x8x32x16xf32>
+  // CHECK: %[[TRANSP:.*]] = vector.transpose %[[READ]], [0, 2, 1, 3] : vector<8x8x32x16xf32> to vector<8x32x8x16xf32>
+  // CHECK: %[[SHAPC:.*]] = vector.shape_cast %[[TRANSP]] : vector<8x32x8x16xf32> to vector<256x128xf32>
+  // CHECK: %[[EMPT:.*]] = tensor.empty() : tensor<256x128xf32>
+  // CHECK: %[[C00:.*]] = arith.constant 0 : index
+  // CHECK: %[[WRIT:.*]] = vector.transfer_write %[[SHAPC]], {{.*}} : vector<256x128xf32>, tensor<256x128xf32>
+  // CHECK: return %[[WRIT]] : tensor<256x128xf32>
+   %0 = tensor.unpack %source inner_dims_pos = [0, 1] inner_tiles = [32, 16] into %dest : tensor<8x8x32x16xf32> -> tensor<256x128xf32>
+   return %0 : tensor<256x128xf32>
+ }
+ module attributes {transform.with_named_sequence} {
+  transform.named_sequence @__transform_main(%arg0: !transform.any_op {transform.readonly}) {
+    %0 = transform.structured.match ops{["tensor.unpack"]} in %arg0 : (!transform.any_op) -> !transform.any_op
+   transform.structured.vectorize %0 : !transform.any_op
+    transform.yield
+  } 
+ }