[MLIR][Vector] Implement TransferOpReduceRank as MaskableOpRewritePattern (#92426)

Implements `TransferOpReduceRank` as a `MaskableOpRewritePattern`.
Allowing to exit gracefully when run on a `vector::transfer_read`
located inside a `vector::MaskOp` instead of generating  `error: 'vector.mask'
op expects only one operation to mask` because the
pattern generated multiple ops inside the MaskOp.

Split of #90835

Author: nujaa

mlir/lib/Dialect/Vector/Transforms/LowerVectorTransfer.cpp

@@ -322,14 +322,20 @@ struct TransferWriteNonPermutationLowering
 ///     %v = vector.transfer_read ...
 ///         permutation_map: (d0, d1, d2, d3) -> (d1, 0, d3)
 ///     vector.broadcast %v
-struct TransferOpReduceRank : public OpRewritePattern<vector::TransferReadOp> {
-  using OpRewritePattern::OpRewritePattern;
+struct TransferOpReduceRank
+    : public MaskableOpRewritePattern<vector::TransferReadOp> {
+  using MaskableOpRewritePattern::MaskableOpRewritePattern;
 
-  LogicalResult matchAndRewrite(vector::TransferReadOp op,
-                                PatternRewriter &rewriter) const override {
+  FailureOr<mlir::Value>
+  matchAndRewriteMaskableOp(vector::TransferReadOp op,
+                            MaskingOpInterface maskOp,
+                            PatternRewriter &rewriter) const override {
     // TODO: support 0-d corner case.
     if (op.getTransferRank() == 0)
       return rewriter.notifyMatchFailure(op, "0-d corner case not supported");
+    // TODO: support masked case.
+    if (maskOp)
+      return rewriter.notifyMatchFailure(op, "Masked case not supported");
 
     AffineMap map = op.getPermutationMap();
     unsigned numLeadingBroadcast = 0;
@@ -369,9 +375,9 @@ struct TransferOpReduceRank : public OpRewritePattern<vector::TransferReadOp> {
             op.getLoc(), originalVecType.getElementType(), op.getSource(),
             op.getIndices());
       }
-      rewriter.replaceOpWithNewOp<vector::BroadcastOp>(op, originalVecType,
-                                                       newRead);
-      return success();
+      return rewriter
+          .create<vector::BroadcastOp>(op.getLoc(), originalVecType, newRead)
+          .getVector();
     }
 
     SmallVector<int64_t> newShape(
@@ -393,9 +399,9 @@ struct TransferOpReduceRank : public OpRewritePattern<vector::TransferReadOp> {
         op.getLoc(), newReadType, op.getSource(), op.getIndices(),
         AffineMapAttr::get(newMap), op.getPadding(), op.getMask(),
         newInBoundsAttr);
-    rewriter.replaceOpWithNewOp<vector::BroadcastOp>(op, originalVecType,
-                                                     newRead);
-    return success();
+    return rewriter
+        .create<vector::BroadcastOp>(op.getLoc(), originalVecType, newRead)
+        .getVector();
   }
 };
 

mlir/test/Dialect/Vector/vector-transfer-permutation-lowering.mlir

@@ -187,3 +187,49 @@ module attributes {transform.with_named_sequence} {
     transform.yield
   }
 }
+
+// -----
+
+
+//       CHECK:   #[[MAP:.*]] = affine_map<(d0, d1, d2, d3) -> (d1, 0, d3)>
+//       CHECK:   func.func @transfer_read_reduce_rank_scalable(
+//  CHECK-SAME:       %[[ARG_0:.*]]: memref<?x?x?x?xf32>) -> vector<8x[4]x2x3xf32> {
+//       CHECK:     %[[C0:.*]] = arith.constant 0 : index
+//       CHECK:     %[[TFR:.*]] = vector.transfer_read %arg0[%[[C0]], %[[C0]], %[[C0]], %[[C0]]]{{.*}} permutation_map = #[[MAP]]} : memref<?x?x?x?xf32>, vector<[4]x2x3xf32>
+//       CHECK:     %[[BC:.*]] = vector.broadcast %[[TFR]] : vector<[4]x2x3xf32> to vector<8x[4]x2x3xf32>
+//       CHECK:     return %[[BC]] : vector<8x[4]x2x3xf32>
+func.func @transfer_read_reduce_rank_scalable(%mem: memref<?x?x?x?xf32>) -> vector<8x[4]x2x3xf32> {
+  %c0 = arith.constant 0 : index
+  %cst_0 = arith.constant 0.000000e+00 : f32
+  %1 = vector.transfer_read %mem[%c0, %c0, %c0, %c0], %cst_0
+    {in_bounds = [true, true, true, true], permutation_map = affine_map<(d0, d1, d2, d3) -> (0, d1, 0, d3)>}
+    : memref<?x?x?x?xf32>, vector<8x[4]x2x3xf32>
+  return %1 : vector<8x[4]x2x3xf32>
+}
+
+// Masked case not supported.
+// CHECK-LABEL:   func.func @masked_transfer_read_reduce_rank(
+//  CHECK-SAME:       %[[ARG_0:.*]]: memref<?x?x?x?xf32>,
+//  CHECK-SAME:       %[[DIM:.*]]: index) -> vector<8x[4]x2x3xf32> {
+//   CHECK-NOT:     vector.broadcast
+//       CHECK:     %[[MASK:.*]] = vector.mask %0 { vector.transfer_read %arg0{{.*}} : memref<?x?x?x?xf32>, vector<8x[4]x2x3xf32> } : vector<[4]x3xi1> -> vector<8x[4]x2x3xf32>
+func.func @masked_transfer_read_reduce_rank(%mem: memref<?x?x?x?xf32>, %dim: index) -> vector<8x[4]x2x3xf32> {
+  %c0 = arith.constant 0 : index
+  %cst_0 = arith.constant 0.000000e+00 : f32
+  %mask = vector.create_mask %dim, %dim: vector<[4]x3xi1>
+  %res = vector.mask %mask { vector.transfer_read %mem[%c0, %c0, %c0, %c0], %cst_0
+    {in_bounds = [true, true, true, true], permutation_map = affine_map<(d0, d1, d2, d3) -> (0, d1, 0, d3)>}
+    : memref<?x?x?x?xf32>, vector<8x[4]x2x3xf32> } : vector<[4]x3xi1> -> vector<8x[4]x2x3xf32>
+  return %res : vector<8x[4]x2x3xf32>
+}
+
+module attributes {transform.with_named_sequence} {
+  transform.named_sequence @__transform_main(%module_op: !transform.any_op {transform.readonly}) {
+    %f = transform.structured.match ops{["func.func"]} in %module_op
+      : (!transform.any_op) -> !transform.any_op
+    transform.apply_patterns to %f {
+      transform.apply_patterns.vector.transfer_permutation_patterns
+    } : !transform.any_op
+    transform.yield
+  }
+}