Improve gpu::MemcpyOp verifier

Emit error in case either of the arguments are not
ranked memrefs or have non identity layout.

Author: arnab-polymage

mlir/lib/Dialect/GPU/IR/GPUDialect.cpp

@@ -1838,8 +1838,14 @@ static void printOffloadingHandler(OpAsmPrinter &printer, Operation *op,
 //===----------------------------------------------------------------------===//
 
 LogicalResult MemcpyOp::verify() {
-  auto srcType = getSrc().getType();
-  auto dstType = getDst().getType();
+  auto srcType = getSrc().getType().dyn_cast<MemRefType>();
+  auto dstType = getDst().getType().dyn_cast<MemRefType>();
+
+  if (!srcType || !dstType)
+    return emitOpError("arguments must be ranked memrefs");
+
+  if (!srcType.getLayout().isIdentity() || !dstType.getLayout().isIdentity())
+    return emitOpError("arguments must have identity layout");
 
   if (getElementTypeOrSelf(srcType) != getElementTypeOrSelf(dstType))
     return emitOpError("arguments have incompatible element type");