Revert "[mlir][vector] Fix emulation of "narrow" type vector.store (llvm#133231)"

This reverts commit 2de936b.

Author: raikonenfnu

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

@@ -593,19 +593,10 @@ struct ConvertVectorStore final : OpConversionPattern<vector::StoreOp> {
     auto origElements = valueToStore.getType().getNumElements();
     // Note, per-element-alignment was already verified above.
     bool isDivisibleInSize = origElements % emulatedPerContainerElem == 0;
-    // Do the trailing dim for source and destination match? If yes, then the
-    // corresponding index must be 0.
-    // FIXME: There's no way to tell for dynamic shapes, so we should bail out.
-    // However, that makes some tests fail, so we need to audit first.
-    auto trailingDim = op.getBase().getType().getShape().back();
-    bool trailingDimsMatch =
-        ShapedType::isDynamic(trailingDim) || trailingDim == origElements;
 
     auto stridedMetadata =
         rewriter.create<memref::ExtractStridedMetadataOp>(loc, op.getBase());
 
-    // FIXME: ATM, we do not test cases where offsets, sizes, or strides are
-    // non-zero. As such, this is not needed.
     OpFoldResult linearizedIndices;
     memref::LinearizedMemRefInfo linearizedInfo;
     std::tie(linearizedInfo, linearizedIndices) =
@@ -617,9 +608,8 @@ struct ConvertVectorStore final : OpConversionPattern<vector::StoreOp> {
             getAsOpFoldResult(adaptor.getIndices()));
 
     std::optional<int64_t> foldedNumFrontPadElems =
-        (isDivisibleInSize && trailingDimsMatch)
-            ? 0
-            : getConstantIntValue(linearizedInfo.intraDataOffset);
+        isDivisibleInSize ? 0
+                          : getConstantIntValue(linearizedInfo.intraDataOffset);
 
     if (!foldedNumFrontPadElems) {
       return rewriter.notifyMatchFailure(
@@ -629,38 +619,15 @@ struct ConvertVectorStore final : OpConversionPattern<vector::StoreOp> {
 
     auto memrefBase = cast<MemRefValue>(adaptor.getBase());
 
-    // RMWs are not needed when:
-    //  * no _partial_ stores are required.
-    // A partial store is defined as a store in which only a part of the
-    // container element is overwritten, e.g.
-    //
-    //    Dest before (8 bits)
-    //        +----------+
-    //        | 11000000 |
-    //        +----------+
-    //
-    //    Dest after storing 0xF at offset 4 (in bits)
-    //        +----------+
-    //        | 11001111 |
-    //        +----------+
-    //
-    // At a higher level, this translats to:
+    // Conditions when atomic RMWs are not needed:
     // 1. The source vector size (in bits) is a multiple of byte size.
-    // 2. The address of the store is aligned to the container type width
-    //    boundary.
-    //
-    // EXAMPLE 1:
-    //  Requires partial store:
-    //    vector.store %arg0, %0[%c3] : memref<13xi2>, vector<4xi2>
+    // 2. The address of the store is aligned to the emulated width boundary.
     //
-    // EXAMPLE 2:
-    //  Does not require a partial store:
-    //    vector.store %arg0, %0[%c4] : memref<13xi2>, vector<4xi2>
-    //
-    // TODO: Take linearizedInfo.linearizedOffset into account. This is
-    // currently not needed/used/exercised as all our tests set offset to 0.
-    bool emulationRequiresPartialStores = *foldedNumFrontPadElems != 0;
-
+    // For example, to store a vector<4xi2> to <13xi2> at offset 4, does not
+    // need unaligned emulation because the store address is aligned and the
+    // source is a whole byte.
+    bool emulationRequiresPartialStores =
+        !isDivisibleInSize || *foldedNumFrontPadElems != 0;
     if (!emulationRequiresPartialStores) {
       // Basic case: storing full bytes.
       auto numElements = origElements / emulatedPerContainerElem;

mlir/test/Dialect/Vector/vector-emulate-narrow-type-unaligned.mlir

@@ -361,74 +361,6 @@ func.func @vector_maskedload_i2_constant_mask_unaligned(%passthru: vector<5xi2>)
 /// vector.store
 ///----------------------------------------------------------------------------------------
 
-// -----
-
-// Most basic example to demonstrate where partial stores are not needed.
-
-func.func @vector_store_i2_const_index_no_partial_store(%arg0: vector<4xi2>) {
-    %0 = memref.alloc() : memref<13xi2>
-    %c4 = arith.constant 4 : index
-    vector.store %arg0, %0[%c4] : memref<13xi2>, vector<4xi2>
-    return
-}
-// CHECK-LABEL:   func.func @vector_store_i2_const_index_no_partial_store(
-// CHECK-SAME:      %[[ARG_0:[0-9]+|[a-zA-Z$._-][a-zA-Z0-9$._-]*]]: vector<4xi2>) {
-// CHECK-NOT:       memref.generic_atomic_rmw
-// CHECK:           %[[ALLOC:.*]] = memref.alloc() : memref<4xi8>
-// CHECK:           %[[UPCAST:.*]] = vector.bitcast %[[ARG_0]] : vector<4xi2> to vector<1xi8>
-// CHECK:           %[[C1:.*]] = arith.constant 1 : index
-// CHECK:           vector.store %[[UPCAST]], %[[ALLOC]]{{\[}}%[[C1]]] : memref<4xi8>, vector<1xi8>
-
-// -----
-
-// Small modification of the example above to demonstrate where partial stores
-// are needed.
-
-func.func @vector_store_i2_const_index_two_partial_stores(%arg0: vector<4xi2>) {
-    %0 = memref.alloc() : memref<13xi2>
-    %c3 = arith.constant 3 : index
-    vector.store %arg0, %0[%c3] : memref<13xi2>, vector<4xi2>
-    return
-}
-
-// CHECK-LABEL:   func.func @vector_store_i2_const_index_two_partial_stores(
-// CHECK-SAME:      %[[ARG_0:[0-9]+|[a-zA-Z$._-][a-zA-Z0-9$._-]*]]: vector<4xi2>) {
-// CHECK:           %[[VAL_1:.*]] = memref.alloc() : memref<4xi8>
-
-// First atomic RMW:
-// CHECK:           %[[IDX_1:.*]] = arith.constant 0 : index
-// CHECK:           %[[MASK_1:.*]] = arith.constant dense<[false, false, false, true]> : vector<4xi1>
-// CHECK:           %[[INIT:.*]] = arith.constant dense<0> : vector<4xi2>
-// CHECK:           %[[SLICE_1:.*]] = vector.extract_strided_slice %[[ARG_0]] {offsets = [0], sizes = [1], strides = [1]} : vector<4xi2> to vector<1xi2>
-// CHECK:           %[[V1:.*]] = vector.insert_strided_slice %[[SLICE_1]], %[[INIT]] {offsets = [3], strides = [1]} : vector<1xi2> into vector<4xi2>
-// CHECK:           memref.generic_atomic_rmw %[[VAL_1]]{{\[}}%[[IDX_1]]] : memref<4xi8> {
-// CHECK:           ^bb0(%[[VAL_8:.*]]: i8):
-// CHECK:             %[[VAL_9:.*]] = vector.from_elements %[[VAL_8]] : vector<1xi8>
-// CHECK:             %[[DOWNCAST_1:.*]] = vector.bitcast %[[VAL_9]] : vector<1xi8> to vector<4xi2>
-// CHECK:             %[[SELECT_1:.*]] = arith.select %[[MASK_1]], %[[V1]], %[[DOWNCAST_1]] : vector<4xi1>, vector<4xi2>
-// CHECK:             %[[UPCAST_1:.*]] = vector.bitcast %[[SELECT_1]] : vector<4xi2> to vector<1xi8>
-// CHECK:             %[[RES_1:.*]] = vector.extract %[[UPCAST_1]][0] : i8 from vector<1xi8>
-// CHECK:             memref.atomic_yield %[[RES_1]] : i8
-// CHECK:           }
-
-// Second atomic RMW:
-// CHECK:           %[[VAL_14:.*]] = arith.constant 1 : index
-// CHECK:           %[[IDX_2:.*]] = arith.addi %[[IDX_1]], %[[VAL_14]] : index
-// CHECK:           %[[VAL_16:.*]] = vector.extract_strided_slice %[[ARG_0]] {offsets = [1], sizes = [3], strides = [1]} : vector<4xi2> to vector<3xi2>
-// CHECK:           %[[V2:.*]] = vector.insert_strided_slice %[[VAL_16]], %[[INIT]] {offsets = [0], strides = [1]} : vector<3xi2> into vector<4xi2>
-// CHECK:           %[[MASK_2:.*]] = arith.constant dense<[true, true, true, false]> : vector<4xi1>
-// CHECK:            memref.generic_atomic_rmw %[[VAL_1]]{{\[}}%[[IDX_2]]] : memref<4xi8> {
-// CHECK:           ^bb0(%[[VAL_20:.*]]: i8):
-// CHECK:             %[[VAL_21:.*]] = vector.from_elements %[[VAL_20]] : vector<1xi8>
-// CHECK:             %[[DONWCAST_2:.*]] = vector.bitcast %[[VAL_21]] : vector<1xi8> to vector<4xi2>
-// CHECK:             %[[SELECT_2:.*]] = arith.select %[[MASK_2]], %[[V2]], %[[DONWCAST_2]] : vector<4xi1>, vector<4xi2>
-// CHECK:             %[[UPCAST_2:.*]] = vector.bitcast %[[SELECT_2]] : vector<4xi2> to vector<1xi8>
-// CHECK:             %[[RES_2:.*]] = vector.extract %[[UPCAST_2]][0] : i8 from vector<1xi8>
-// CHECK:             memref.atomic_yield %[[RES_2]] : i8
-// CHECK:           }
-
-// -----
-
 func.func @vector_store_i2_const_index_two_partial_stores(%arg0: vector<3xi2>) {
     %src = memref.alloc() : memref<3x3xi2>
     %c0 = arith.constant 0 : index

mlir/test/Dialect/Vector/vector-emulate-narrow-type.mlir

@@ -439,11 +439,6 @@ func.func @vector_store_i4(%arg0: vector<8xi4>, %arg1: index, %arg2: index) {
 
 // -----
 
-// FIXME: This example assumes that the store happens at a byte boundary, but
-// that's not guaranteed. Below is a counter-example with specific dimensions:
-//    vector.store %arg0, %0[0, 3] : memref<2x13xi4>, vector<8xi4>
-// TODO: Revisit post #136797
-
 func.func @vector_store_i4_dynamic(%arg0: vector<8xi4>, %arg1: index, %arg2: index, %arg3: index, %arg4: index) {
     %0 = memref.alloc(%arg1, %arg2) : memref<?x?xi4>
     vector.store %arg0, %0[%arg3, %arg4] : memref<?x?xi4>, vector<8xi4>