[PATCH] D71082: Allow system header to provide their own implementation of some builtin

[Reid Kleckner via Phabricator via cfe-commits]

rnk added a comment.

I agree, raising -fgnuc-version is not an acceptable workaround, and we can't ship a clang that doesn't work with old versions of glibc. I think we need a different workaround. The simplest one I can think of is to make `__warn_memset_zero_len` a recognized builtin that generates no code.

Clang already emits this warning when it would be useful, before inlining. `memset(ptr, c, n)` when `n` is zero at runtime or at compile time after inlining should not be a warning or link error.

I believe we also branched 10.0 between this change and its revert. Can you please follow up and merge the eventual fix to the release?


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D71082/new/

https://reviews.llvm.org/D71082