[PATCH] D72579: Evaluate __{c11_,}atomic_is_lock_free to 0 (avoid libcall) if larger than MaxAtomicPromoteWidth

[Eli Friedman via Phabricator via cfe-commits]

efriedma added a comment.

Eagerly evaluating based on MaxAtomicPromoteWidth seems fine... assuming we're actually setting MaxAtomicPromoteWidth to something appropriate.  The value on PowerPC looks wrong.

If we're worried about constant-evaluating it in contexts where gcc doesn't, we can generate a diagnostic to prevent that from happening.  (See the handling of Builtin::BIstrcmp.)


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D72579/new/

https://reviews.llvm.org/D72579