[PATCH] D23692: Interpret strlen as constexpr for GCC Compatibility

[Erich Keane via cfe-commits]

erichkeane abandoned this revision.
erichkeane added a comment.

In https://reviews.llvm.org/D23692#520081, @rsmith wrote:

> This is not a conforming extension. We are explicitly not allowed to make standard library functions `constexpr` if the standard doesn't say they are; see [constexpr.functions] (17.6.5.6) in the C++ standard. Clang previously used to allow constant-folding `strlen` calls, but we removed that support intentionally for this reason.
>
> It would seem reasonable for this constant-folding to be enabled for `strlen` if the callee was explicitly marked as `constexpr` in the source code. That way, if the standard library chooses to mark it as `constexpr` as a (currently) non-conforming extension, we would provide an optimized implementation.


Ok, thank you for your prompt response.  I'll see if that is a viable solution for this case.

Thanks!


Repository:
  rL LLVM

https://reviews.llvm.org/D23692