[PATCH] D59038: [8.0 Regression] Fix handling of `__builtin_constant_p` inside the enable_if attribute.

Thu Mar 7 03:45:41 PST 2019

EricWF added a comment.

In D59038#1421310 <https://reviews.llvm.org/D59038#1421310>, @hans wrote:

> I think I'll have to defer to Richard for reviewing this, since I'm not familiar with the code. Since it's a regression we probably want to merge it to clang 8. Can you give any guidance to how bad a regression this is, e.g. does it break some important piece of code?

It breaks `absl::StrFormat` [1][2]. And it breaks libstdc++'s `std::string_view` inside unevaluated constant expressions [3].

This regression is a problem for Abseil.

[1] https://godbolt.org/z/Q_J2JP
[2] https://github.com/abseil/abseil-cpp/issues/271
[3 https://godbolt.org/z/Fg1sqM]

Repository:
  rC Clang

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  https://reviews.llvm.org/D59038/new/

https://reviews.llvm.org/D59038