parse empty operand bundles list

Author: Lancern

mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp

@@ -289,6 +289,9 @@ static std::optional<ParseResult> parseOpBundles(
   if (p.parseOptionalLSquare())
     return std::nullopt;
 
+  if (succeeded(p.parseOptionalRSquare()))
+    return success();
+
   auto bundleParser = [&] {
     return parseOneOpBundle(p, opBundleOperands, opBundleOperandTypes,
                             opBundleTags);

mlir/test/Target/LLVMIR/llvmir.mlir

@@ -2631,6 +2631,16 @@ llvm.func @intel_reqd_sub_group_size() attributes {intel_reqd_sub_group_size = 3
 
 llvm.func @foo()
 
+llvm.func @call_with_empty_opbundle() {
+  llvm.call @foo() [] : () -> ()
+  llvm.return
+}
+
+//      CHECK: define void @call_with_empty_opbundle() {
+// CHECK-NEXT:   call void @foo()
+// CHECK-NEXT:   ret void
+// CHECK-NEXT: }
+
 llvm.func @call_with_opbundle() {
   %0 = llvm.mlir.constant(1 : i32) : i32
   %1 = llvm.mlir.constant(2 : i32) : i32