[Mlir-commits] [mlir] [MLIR][XeGPU][XeVM] XeGPU to XeVM: Add lowering for xegpu.dpas_mx (PR #196981)

[Artem Kroviakov]

================
@@ -1066,6 +1076,78 @@ class AtomicRMWToXeVMPattern : public OpConversionPattern<xegpu::AtomicRMWOp> {
   }
 };
 
+class DpasMxToXeVMPattern : public OpConversionPattern<xegpu::DpasMxOp> {
+  using OpConversionPattern::OpConversionPattern;
+  LogicalResult
+  matchAndRewrite(xegpu::DpasMxOp op, xegpu::DpasMxOp::Adaptor adaptor,
+                  ConversionPatternRewriter &rewriter) const override {
+    auto loc = op.getLoc();
+    auto ctxt = rewriter.getContext();
+    auto aTy = op.getA().getType();
+    auto bTy = op.getB().getType();
+    auto resultType = cast<VectorType>(op.getType());
+
+    auto chipStr = xegpu::getChipStr(op);
+    if (!chipStr)
+      return rewriter.notifyMatchFailure(op, "cannot determine target chip");
+
+    const auto *uArch = xegpu::uArch::getUArch(*chipStr);
+    if (!uArch)
+      return rewriter.notifyMatchFailure(op, "unsupported target uArch");
+
+    // TODO: Add supported shape check
+
+    xevm::ElemType precATy = encodePrecision(aTy.getElementType());
+    xevm::ElemType precBTy = encodePrecision(bTy.getElementType());
+    Value c = op.getAcc();
+    if (!c) {
+      auto elementTy = resultType.getElementType();
+      Attribute initValueAttr;
+      if (isa<FloatType>(elementTy))
+        initValueAttr = FloatAttr::get(elementTy, 0.0);
+      else
+        initValueAttr = IntegerAttr::get(elementTy, 0);
+      c = arith::ConstantOp::create(
+          rewriter, loc, DenseElementsAttr::get(resultType, initValueAttr));
+    }
+
+    Value aVec = adaptor.getA();
+    Value bVec = adaptor.getB();
+    auto aVecTy = cast<VectorType>(aVec.getType());
+    auto bVecTy = cast<VectorType>(bVec.getType());
+    if (aVecTy.getElementTypeBitWidth() == 4)
+      aVec = vector::BitCastOp::create(
+          rewriter, loc,
+          VectorType::get(aVecTy.getNumElements() / 2, rewriter.getI8Type()),
+          aVec);
+    if (bVecTy.getElementTypeBitWidth() == 4)
+      bVec = vector::BitCastOp::create(
+          rewriter, loc,
+          VectorType::get(bVecTy.getNumElements() / 2, rewriter.getI8Type()),
+          bVec);
+    auto cvecty = cast<VectorType>(c.getType());
+    xevm::ElemType precCTy = encodePrecision(cvecty.getElementType());
+    xevm::ElemType precDTy = encodePrecision(resultType.getElementType());
+    VectorType cNty =
----------------
akroviakov wrote:

How is it different from 
`cast<VectorType>(adaptor.getAcc().getType())` or `getTypeConverter()->convertType(resultType)`?

https://github.com/llvm/llvm-project/pull/196981