[PATCH] D144844: [C++20] [Modules] Offer -fno-import-inter-module-function-defs to avoid duplicated compilation in modules

[David Blaikie via Phabricator via cfe-commits]

dblaikie added a comment.

Seem to recall @iains and others were concerned about the number of modules flags - this one I'd be inclined to suggest we shouldn't add if possible. If one way or the other is generally better - we should, at least initially, dictate that behavior entirely until someone can demonstrate divergent use cases that seem reasonable to support but must have different behavior here.

The performance of cross-module inlining could be achieved with something like ThinLTO if we were to lean in favor of not allowing cross-module inlining by default, for instance.

But if there are particular idioms where cross-module inlining is disadvantageous, perhaps we can implement better ways for clang to detect them (or if they're undetectable, offer users a way to annotate their code, maybe).

Could we key off -Os or -Oz or some other existing optimization/compile time tradeoff flags instead of introducing a new flag?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D144844/new/

https://reviews.llvm.org/D144844