[Mlir-commits] [mlir] [mlir][vector] Add support for linearizing Extract, ExtractStridedSlice, Shuffle VectorOps in VectorLinearize (PR #88204)

[Diego Caballero]

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@@ -103,6 +108,252 @@ struct LinearizeVectorizable final
     return success();
   }
 
+private:
+  unsigned targetVectorBitWidth;
+};
+
+/// This pattern converts the ExtractStridedSliceOp into a ShuffleOp that works
+/// on a linearized vector.
+/// Following,
+///   vector.extract_strided_slice %source
+///         { offsets = [..], strides = [..], sizes = [..] }
+/// is converted to :
+///   %source_1d = vector.shape_cast %source
+///   %out_1d = vector.shuffle %source_1d, %source_1d [ shuffle_indices_1d ]
+///   %out_nd = vector.shape_cast %out_1d
+/// `shuffle_indices_1d` is computed using the offsets and sizes of the
+/// extraction.
+struct LinearizeVectorExtractStridedSlice final
+    : public mlir::OpConversionPattern<mlir::vector::ExtractStridedSliceOp> {
+  using OpConversionPattern::OpConversionPattern;
+  LinearizeVectorExtractStridedSlice(
+      const TypeConverter &typeConverter, MLIRContext *context,
+      unsigned targetVectBitWidth = std::numeric_limits<unsigned>::max(),
+      PatternBenefit benefit = 1)
+      : OpConversionPattern(typeConverter, context, benefit),
+        targetVectorBitWidth(targetVectBitWidth) {}
+
+  LogicalResult
+  matchAndRewrite(vector::ExtractStridedSliceOp extractOp, OpAdaptor adaptor,
+                  ConversionPatternRewriter &rewriter) const override {
+    auto dstType = getTypeConverter()->convertType(extractOp.getType());
+    assert(!(extractOp.getVector().getType().isScalable() ||
+             dstType.cast<VectorType>().isScalable()) &&
+           "scalable vectors are not supported.");
+    if (!isLessThanTargetBitWidth(extractOp, targetVectorBitWidth))
+      return rewriter.notifyMatchFailure(
+          extractOp, "Can't flatten since targetBitWidth <= OpSize");
+
+    auto offsets = extractOp.getOffsets();
+    auto sizes = extractOp.getSizes();
+    auto strides = extractOp.getStrides();
+    if (!isConstantIntValue(strides[0], 1))
+      return rewriter.notifyMatchFailure(
+          extractOp, "Strided slice with stride != 1 is not supported.");
+    Value srcVector = adaptor.getVector();
+    // If kD offsets are specified for nd source vector (n > k), the granularity
+    // of the extraction is greater than 1. In this case last (n-k) dimensions
+    // form the extraction granularity.
+    // Example :
+    //  vector.extract_strided_slice %src {
+    //      offsets = [0, 0], sizes = [2, 2], strides = [1, 1]} :
+    //      vector<4x8x8xf32> to vector<2x2x8xf32>
+    // Here, extraction granularity is 8.
+    int64_t extractGranularitySize = 1;
+    auto n = extractOp.getSourceVectorType().getRank();
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dcaballe wrote:

nit: please, spell out the type when it's not literally redundant in the statement.

https://github.com/llvm/llvm-project/pull/88204