[BACKEND] Add generic support of convert_layout from distributed to shared (#1025)

lib/Dialect/TritonGPU/IR/Dialect.cpp

@@ -254,6 +254,11 @@ SmallVector<unsigned> getOrder(const Attribute &layout) {
   }
 };
 
+bool isaDistributedLayout(const Attribute &layout) {
+  return layout.isa<BlockedEncodingAttr>() || layout.isa<MmaEncodingAttr>() ||
+         layout.isa<SliceEncodingAttr>();
+}
+
 } // namespace gpu
 } // namespace triton
 } // namespace mlir