[PATCH] D137205: [clang-tidy] Add performance-unnecessary-copy-on-last-use check

Mon Mar 27 11:24:37 PDT 2023

firewave added a comment.

In D137205#4225006 <https://reviews.llvm.org/D137205#4225006>, @Febbe wrote:

> Yes, I agree, while I can't understand, why someone still wants to use only c++11 I can totally understand, that a single Software Engineer can't do anything about this, when the corporation does not permit it. 
> But it should not be removed, since this warning can still show some pitfalls in performance critical code. A way in c++11 to fix the warning, is to create a functor, instead of a lambda.

Well, compatibility with older platforms. And I personally have lots of quarrels with modern (and more recently even early) C++, but let's not get into that. Being able to move within captures is not one of them though...

I still think being able to tune that check for certain parts would be helpful - especially if it would not be fixable with a fix-it. It should also help with applying these findings to an existing code base as you could enable it incrementally (especially if you need to introduce something like functors).
Recent Clang additions like `misc-const-correctness` or `-Wunsafe-buffer-usage` would have profited from being just a bit more granular as they produce such a flood of warnings even for small code bases which makes it quite troublesome to adopt the code for those warnings as some of them are not just applying the fix-it but also need to be looked at in the bigger picture to see if they might not impact things negatively in the future.

Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D137205/new/

https://reviews.llvm.org/D137205