[Bug c++/65985] New: compiler segfault with assert() in constexpr constructor body

[Bug c++/65985] New: compiler segfault with assert() in constexpr constructor body

[rhalbersma at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65985

            Bug ID: 65985
           Summary: compiler segfault with assert() in constexpr
                    constructor body
           Product: gcc
           Version: 5.1.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rhalbersma at gmail dot com
  Target Milestone: ---

The following code segfaults with -std=c++1y for g++ 5.1.0 and trunk 20150502
on the combination of constexpr and assert() in the constructor body (removing
either the constexpr keyword everywhere or the assert() will compile cleanly).  

#include <cassert>

class Angle
{
        int degrees = 0;

        constexpr auto invariant() const noexcept
        {
                return 0 <= degrees && degrees < 360;
        }

public:
        explicit constexpr Angle(int n) noexcept
        :
                degrees{n % 360}
        {
                assert(invariant());
        }

        /* implicit */ constexpr operator auto() const noexcept
        {
                return degrees;
        }          
};

int main() 
{
        static_assert(Angle{360} == 0, "");
}

This code correctly compiles with -std=c++14 from Clang 3.3 and higher.

[Bug c++/65985] compiler segfault with assert() in constexpr constructor body

[rhalbersma at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65985

--- Comment #1 from rhalbersma <rhalbersma at gmail dot com> ---
See also LWG active issue 2234
http://cplusplus.github.io/LWG/lwg-active.html#2234

[Bug c++/65985] [5/6 Regression] compiler segfault with assert() in constexpr constructor body

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65985

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |5.2
            Summary|compiler segfault with      |[5/6 Regression] compiler
                   |assert() in constexpr       |segfault with assert() in
                   |constructor body            |constexpr constructor body

[Bug c++/65985] [5/6 Regression] compiler segfault with assert() in constexpr constructor body

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65985

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |DUPLICATE

--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Actually I think it's a dup.

*** This bug has been marked as a duplicate of bug 65973 ***

[Bug c++/65985] [5/6 Regression] compiler segfault with assert() in constexpr constructor body

[daniel.kruegler at googlemail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65985

--- Comment #4 from Daniel Krügler <daniel.kruegler at googlemail dot com> ---
(In reply to Marek Polacek from comment #3)
> Actually I think it's a dup.

Can we nonetheless ensure that the assert example would become a test case?
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Subject: [Bug c++/65973] [5/6 Regression] segmentation fault when compiling C++14 code
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https://gcc.gnu.org/bugzilla/show_bug.cgi?ide973

--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
When fixing this, remember to also add the testcase in PR65985.