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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/94929] [8 Regression] GCC 8 chokes on std::max in alignas
Date: Sun, 03 May 2020 08:49:47 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D94929

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|                            |6.4.0, 7.5.0, 8.4.0
                 CC|                            |polacek at redhat dot com
     Ever confirmed|0                           |1
           Keywords|                            |rejects-valid
             Status|RESOLVED                    |NEW
      Known to work|                            |10.0, 11.0, 5.5.0, 9.2.0
   Last reconfirmed|                            |2020-05-03
         Resolution|DUPLICATE                   |---

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Hmm, although this was fixed for gcc 9.2 by the patch for PR 90736 it seems=
 to
be a different root cause. This compiled with GCC 5 but not 6, 7 or 8:

template<typename T>
constexpr const T& max(const T& a, const T& b) { return a < b ? b : a; }

struct One {};
struct Two {};
struct Foo { alignas(max(alignof(One), alignof(Two))) char value; };

This regressed with r230365, "Merge C++ delayed folding branch."

Marek, looks like backporting r272219 would fix this.=