[Mlir-commits] [mlir] [mlir][amdgpu] implement amdgpu.sparse_mfma wrapper for smfmac instructions (PR #171968)

[Jakub Kuderski]

================
@@ -1291,6 +1413,49 @@ struct ScaledMFMAOpLowering : public ConvertOpToLLVMPattern<ScaledMFMAOp> {
   }
 };
 
+struct SparseMFMAOpLowering : public ConvertOpToLLVMPattern<SparseMFMAOp> {
+  SparseMFMAOpLowering(const LLVMTypeConverter &converter, Chipset chipset)
+      : ConvertOpToLLVMPattern<SparseMFMAOp>(converter), chipset(chipset) {}
+
+  Chipset chipset;
+
+  LogicalResult
+  matchAndRewrite(SparseMFMAOp op, SparseMFMAOpAdaptor adaptor,
+                  ConversionPatternRewriter &rewriter) const override {
+    Location loc = op.getLoc();
+    auto outType =
+        typeConverter->convertType<VectorType>(op.getDestC().getType());
+    if (!outType)
+      return rewriter.notifyMatchFailure(op, "type conversion failed");
+
+    // smfmac is supported on gfx942 and gfx950
+    if (chipset.majorVersion != 9 || chipset < kGfx942)
+      return op->emitOpError("sparse MFMA (smfmac) only supported on gfx942+");
+    bool isGfx950 = chipset >= kGfx950;
+
+    Value a = convertSparseMFMAVectorOperand(rewriter, loc,
+                                             adaptor.getSourceA(), isGfx950);
+    Value b = convertSparseMFMAVectorOperand(rewriter, loc,
+                                             adaptor.getSourceB(), isGfx950);
+    Value c = adaptor.getDestC();
+
+    std::optional<StringRef> maybeIntrinsic = smfmacOpToIntrinsic(op, isGfx950);
+
+    if (!maybeIntrinsic.has_value())
----------------
kuhar wrote:

```suggestion
    std::optional<StringRef> maybeIntrinsic = smfmacOpToIntrinsic(op, isGfx950);
    if (!maybeIntrinsic.has_value())
```

https://github.com/llvm/llvm-project/pull/171968