[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(
----------------
akroviakov wrote:

Can't we call a type conversion on the result type to get a 1d vector type at creation of `c` in this branch? 
If we also retrieve c through the adaptor
 ```
Value c = adaptor.getAcc();
```
then we should not need the `c` shape cast below (either way we have a 1d vector). 

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