Initial work on memref ops

Author: Jaddyen

mlir/lib/Conversion/MemRefToEmitC/MemRefToEmitC.cpp

@@ -77,6 +77,31 @@ struct ConvertAlloca final : public OpConversionPattern<memref::AllocaOp> {
   }
 };
 
+struct ConvertCopy final : public OpConversionPattern<memref::CopyOp> {
+  using OpConversionPattern::OpConversionPattern;
+
+  LogicalResult
+  matchAndRewrite(memref::CopyOp op, OpAdaptor operands,
+                  ConversionPatternRewriter &rewriter) const override {
+    return failure();
+  }
+};
+
+static Type convertGlobalMemrefTypeToEmitc(MemRefType type,
+                                           const TypeConverter &typeConverter) {
+  Type elementType = typeConverter.convertType(type.getElementType());
+  Type arrayTy = elementType;
+  // Shape has the outermost dim at index 0, so need to walk it backwards
+  auto shape = type.getShape();
+  if (shape.empty()) {
+    arrayTy = emitc::ArrayType::get({1}, arrayTy);
+  } else {
+    // For non-zero dimensions, use the original shape
+    arrayTy = emitc::ArrayType::get(shape, arrayTy);
+  }
+  return arrayTy;
+}
+
 struct ConvertGlobal final : public OpConversionPattern<memref::GlobalOp> {
   using OpConversionPattern::OpConversionPattern;
 
@@ -95,7 +120,8 @@ struct ConvertGlobal final : public OpConversionPattern<memref::GlobalOp> {
           op.getLoc(), "global variable with alignment requirement is "
                        "currently not supported");
     }
-    auto resultTy = getTypeConverter()->convertType(op.getType());
+    auto resultTy =
+        convertGlobalMemrefTypeToEmitc(op.getType(), *getTypeConverter());
     if (!resultTy) {
       return rewriter.notifyMatchFailure(op.getLoc(),
                                          "cannot convert result type");
@@ -114,6 +140,15 @@ struct ConvertGlobal final : public OpConversionPattern<memref::GlobalOp> {
     bool externSpecifier = !staticSpecifier;
 
     Attribute initialValue = operands.getInitialValueAttr();
+    if (op.getType().getRank() == 0) {
+      auto elementsAttr = llvm::cast<ElementsAttr>(*op.getInitialValue());
+      auto scalarValue = elementsAttr.getSplatValue<Attribute>();
+
+      // Convert scalar value to single-element array
+      initialValue = DenseElementsAttr::get(
+          RankedTensorType::get({1}, elementsAttr.getElementType()),
+          {scalarValue});
+    }
     if (isa_and_present<UnitAttr>(initialValue))
       initialValue = {};