[clang] [OpenACC][CIR] Implement 'async' lowering. (PR #136626)

[Andy Kaylor via cfe-commits]

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@@ -97,11 +97,13 @@ class OpenACCClauseCIREmitter final
 
   // Handle a clause affected by the 'device-type' to the point that they need
   // to have the attributes added in the correct/corresponding order, such as
-  // 'num_workers' or 'vector_length' on a compute construct.
-  mlir::ArrayAttr
-  handleDeviceTypeAffectedClause(mlir::ArrayAttr existingDeviceTypes,
-                                 mlir::Value argument,
-                                 mlir::MutableOperandRange &argCollection) {
+  // 'num_workers' or 'vector_length' on a compute construct. For cases where we
+  // don't have an argument that needs to be added to an additional one (such as
+  // asyncOnly) we can use this with 'argument' as std::nullopt.
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andykaylor wrote:

Maybe mention that argCollection must not be null if an argument is provided?

https://github.com/llvm/llvm-project/pull/136626