[Mlir-commits] [mlir] [MLIR][XeGPU] XeVM lowering support for load_matrix/store_matrix (PR #162780)

[Adam Siemieniuk]

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@@ -503,6 +506,187 @@ class LoadStoreToXeVMPattern : public OpConversionPattern<OpType> {
   }
 };
 
+// Lower xegpu::CreateMemDescOp to memref::ViewOp. Since SLM access instructions
+// on Xe2 and Xe3 operate on 32-bit or 64-bit units, all data types smaller than
+// 32 bits will be converted to 32 bits.
+class CreateMemDescOpPattern final
+    : public OpConversionPattern<xegpu::CreateMemDescOp> {
+public:
+  using OpConversionPattern<xegpu::CreateMemDescOp>::OpConversionPattern;
+  LogicalResult
+  matchAndRewrite(xegpu::CreateMemDescOp op, OpAdaptor adaptor,
+                  ConversionPatternRewriter &rewriter) const override {
+    TypedValue<MemRefType> src = op.getSource();
+    auto resTy = cast<xegpu::MemDescType>(op.getResult().getType());
+
+    // Create the result MemRefType with the same shape, element type, and
+    // memory space
+    auto newResTy = getTypeConverter()->convertType<MemRefType>(resTy);
+
+    Value zero = arith::ConstantIndexOp::create(rewriter, op.getLoc(), 0);
+    auto viewOp = memref::ViewOp::create(rewriter, op.getLoc(), newResTy,
+                                         Value(src), zero, ValueRange());
+    rewriter.replaceOp(op, viewOp);
+    return success();
+  }
+};
+
+class MemDescSubviewOpPattern final
+    : public OpConversionPattern<xegpu::MemDescSubviewOp> {
+public:
+  using OpConversionPattern<xegpu::MemDescSubviewOp>::OpConversionPattern;
+  LogicalResult
+  matchAndRewrite(xegpu::MemDescSubviewOp op, OpAdaptor adaptor,
+                  ConversionPatternRewriter &rewriter) const override {
+    return rewriter.notifyMatchFailure(
+        op, "MemDescSubviewOp are not supported on Xe2/Xe3 architecture.");
----------------
adam-smnk wrote:

To me, it's still an open question how we'll help users across different generations.
A separate arch specific verifier pass might be needed.

For now, I'd be leaning toward leaving this as is just to slightly improve discoverability when ppl start wondering why this is missing or not working.

https://github.com/llvm/llvm-project/pull/162780