[PATCH] D109175: [openmp] Add clang cc1 option -fopenmp-skip-deferred-diags

Thu Sep 2 12:40:42 PDT 2021

wenlei added a comment.

In D109175#2980446 <https://reviews.llvm.org/D109175#2980446>, @lebedev.ri wrote:

> In D109175#2980333 <https://reviews.llvm.org/D109175#2980333>, @weiwang wrote:
>
>> Our internal codebase never uses the target directive. Once the deferred diags is bypassed, we observed 18% e2e build time improvement.
>
> Is that with `-fopenmp` or without?
> That seems, kinda a lot more than i would have expected,
> perhaps there are some other ways to reduce the overhead other than this approach?

Yeah, though the slow down in build time is blocking us from moving to newer llvm for many projects. Currently I think it makes sense to give user the option to decide whether they want faster build or better diagnostics. Of course if the slow down is fully addressed in the future, the switch could be removed too.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D109175/new/

https://reviews.llvm.org/D109175