llvm-project

775ad3e4 - [flang][acc] Ensure all acc.loop get a default parallelism determination mode (#143623)

[flang][acc] Ensure all acc.loop get a default parallelism determination mode (#143623) This PR updates the flang lowering to explicitly implement the OpenACC rules: - As per OpenACC 3.3 standard section 2.9.6 independent clause: A loop construct with no auto or seq clause is treated as if it has the independent clause when it is an orphaned loop construct or its parent compute construct is a parallel construct. - As per OpenACC 3.3 standard section 2.9.7 auto clause: When the parent compute construct is a kernels construct, a loop construct with no independent or seq clause is treated as if it has the auto clause. - Loops in serial regions are `seq` if they have no other parallelism marking such as gang, worker, vector. For now the `acc.loop` verifier has not yet been updated to enforce this.