[Bug c++/107161] gcc doesn't constant fold member if any other member is mutable

[vanyacpp at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107161

--- Comment #2 from Ivan Sorokin  ---
> Do constexpr/consteval work in such circumstances?

Yes, constexpr works for variables like "p.a":

extern constexpr mytype p = {1, 2};

int foo()
{
constexpr int t = p.a + 10;
return t;
}

foo():
mov eax, 11
ret

https://godbolt.org/z/K9a69E4ar

[Bug c++/107161] gcc doesn't constant fold member if any other member is mutable

[rguenth at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107161

--- Comment #1 from Richard Biener  ---
GCC relies on 'p' being in .rodata for the folding which of course cannot be
the case with a mutable member.  Note the frontend clears the 'const' from the
declaration because of the mutable member and we have no way to distinguish
constant from non-constant members here.

Do constexpr/consteval work in such circumstances?

[Bug c++/107161] gcc doesn't constant fold member if any other member is mutable

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107161

Andrew Pinski  changed:

   What|Removed |Added

   Severity|normal  |enhancement
   Keywords||missed-optimization