From 72619d101fda15a98b8f406e6009c5da06e3f835 Mon Sep 17 00:00:00 2001
From: Mogball <jeffniu22@gmail.com>
Date: Tue, 8 Feb 2022 21:13:58 +0000
Subject: [PATCH] [mlir][ods] NFC fix tblgen crash with empty assembly format

---
 mlir/tools/mlir-tblgen/AttrOrTypeFormatGen.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mlir/tools/mlir-tblgen/AttrOrTypeFormatGen.cpp b/mlir/tools/mlir-tblgen/AttrOrTypeFormatGen.cpp
index d697ad2b4ea4..2a1fcf936237 100644
--- a/mlir/tools/mlir-tblgen/AttrOrTypeFormatGen.cpp
+++ b/mlir/tools/mlir-tblgen/AttrOrTypeFormatGen.cpp
@@ -812,6 +812,8 @@ LogicalResult DefFormatParser::verify(SMLoc loc,
                                 it.value().getName());
     }
   }
+  if (elements.empty())
+    return success();
   // A `struct` directive that contains optional parameters cannot be followed
   // by a comma literal, which is ambiguous.
   for (auto it : llvm::zip(elements.drop_back(), elements.drop_front())) {