parse empty operands within a bundle

Author: Lancern

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

@@ -264,15 +264,11 @@ static ParseResult parseOneOpBundle(
   if (p.parseLParen())
     return failure();
 
-  if (p.parseOperandList(operands))
-    return failure();
-  if (p.parseColon())
-    return failure();
-  if (p.parseTypeList(types))
-    return failure();
-
-  if (p.parseRParen())
-    return failure();
+  if (p.parseOptionalRParen()) {
+    if (p.parseOperandList(operands) || p.parseColon() ||
+        p.parseTypeList(types) || p.parseRParen())
+      return failure();
+  }
 
   opBundleOperands.push_back(std::move(operands));
   opBundleOperandTypes.push_back(std::move(types));

mlir/test/Target/LLVMIR/llvmir.mlir

@@ -2641,6 +2641,16 @@ llvm.func @call_with_empty_opbundle() {
 // CHECK-NEXT:   ret void
 // CHECK-NEXT: }
 
+llvm.func @call_with_empty_opbundle_operands() {
+  llvm.call @foo() ["tag"()] : () -> ()
+  llvm.return
+}
+
+//      CHECK: define void @call_with_empty_opbundle_operands() {
+// CHECK-NEXT:   call void @foo() [ "tag"() ]
+// 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