[flang][acc] Extend coverage for offload target verifier (#220468) This PR builds upon acc::isValidSymbolUse and acc::isValidValueUse to ensure that FIR and CUF specific handling is considered. FIR now provides fir::acc::isValidSymbolUse and fir::acc::isValidValueUse. Symbol uses treat Fortran runtime and non-host CUDA Fortran procedures as valid, and accept fir.use_stmt references that may have no local definition. Value uses accept FIR scalars that are passed by value, including those reachable through declare and similar wrappers, and allow trivially copyable scalars into CUF kernels. The OpenACC analysis delegates to these utilities. The dialect helpers are extended so symbols defined in a gpu.module and arguments of an acc routine are treated as already on the device. GitOrigin-RevId: 93aa6c4b53d28c19aeeaa8c3f00ba07ebf24a10b
Flang is a ground-up implementation of a Fortran front end written in modern C++. It started off as the f18 project (https://github.com/flang-compiler/f18) with an aim to replace the previous flang project (https://github.com/flang-compiler/flang) and address its various deficiencies. F18 was subsequently accepted into the LLVM project and rechristened as Flang.
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