[flang-dev] Flang driver - next steps

[Andrzej Warzynski via flang-dev]

Hi Mehdi,

On 29/09/2021 19:24, Mehdi AMINI wrote:
> Something annoying with the clang driver is the lack of
> reproducibility of the optimization pipeline (`clang -O3` and `opt
> -O3` gives different results).
> It'd be great if flang was set up from the beginning to avoid this
> kind of issues!

Thanks for pointing this out! This should be relatively easy to achieve 
within LLVM Flang if we have a replacement for LLVM's `opt`.  IIUC, 
that's what `tco` [1] is for. We just need to make sure that `flang-new` 
and `tco` share pass-pipeline definitions. Are there any other reasons 
for `clang -O3` and `opt -O3` to give different results?

-Andrzej

[1] 
https://github.com/flang-compiler/f18-llvm-project/blob/fir-dev/flang/tools/tco/tco.cpp