[flang-commits] [flang] [flang] Add HLFIR-to-FIR pass pipeline extension points (PR #212194)

[Valentin Churavy via flang-commits]

vchuravy wrote:

Submitted as a stack so that folks can see my end-goal. I am using the changes here to develop an Enzyme-MLIR plugin for flang to differentiate through Fortran (see https://github.com/EnzymeAD/Enzyme/pull/2968)

The final PR in the stack contains a example plugin. 

https://github.com/llvm/llvm-project/pull/212194