Index: mlir/lib/Conversion/SCFToGPU/SCFToGPU.cpp
===================================================================
--- mlir/lib/Conversion/SCFToGPU/SCFToGPU.cpp
+++ mlir/lib/Conversion/SCFToGPU/SCFToGPU.cpp
@@ -517,6 +517,16 @@
     }
     cloningMap.map(iv, newIndex);
   }
+
+  // Propagate custom user defined optional attributes, that can be used at
+  // later stage, such as extension data for GPU kernel dispatch
+  for (const auto &namedAttr : parallelOp.getAttrs()) {
+    if (namedAttr.first == gpu::getMappingAttrName() ||
+        namedAttr.first == ParallelOp::getOperandSegmentSizeAttr())
+      continue;
+    launchOp.setAttr(namedAttr.first, namedAttr.second);
+  }
+
   Block *body = parallelOp.getBody();
   worklist.reserve(worklist.size() + body->getOperations().size());
   for (Operation &op : llvm::reverse(body->without_terminator()))