llvm-project

ef4fbb55 - [flang][OpenACC] add pass to bufferize fir.box recipes (#163543)

[flang][OpenACC] add pass to bufferize fir.box recipes (#163543) When working on privatization, it is easier to work with fir.box explicitly in memory, otherwise, there is no way to express that the fir.box will end-up being a descriptor address in FIR which makes it hard to deal with data management. However, introducing fir.ref<fir.box> early can pessimize early HLFIR optimization because it is harder to reason about the aliasing of `fir.ref<fir.box>` because of the extra memory indirection. This patch introduces a pass that turns acc `!fir.box<T>` recipes into `!fir.ref<!fir.box<T>>` recipes and updated the related recipe usages to use `!fir.ref<!fir.box<T>>` (creating new alloca+store+load). It is added to flang and not OpenACC because it is specific to the `fir.box` type, so it makes little sense to make it an OpenACC generic pass and to create a new OpenACC dialect type interface for this use case.