[Bug c++/127668] GCC `__builtin_bitreverseg` ICEs (segfault in the C++ mangler) when applied to a dependent operand in a template signature

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127668

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org
           Assignee|unassigned at gcc dot gnu.org      |jakub at gcc dot gnu.org
             Status|NEW                         |ASSIGNED

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 65725
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=65725&action=edit
gcc17-pr127668.patch

Untested fix.

This mangles it similarly to e.g.
template <typename T>auto foo (T t) -> decltype (__builtin_popcountg (t)) {
return t; }template int foo <unsigned> (unsigned);
Just for the latter we actually have a builtin, while for
__builtin_bswapg/__builtin_bitreverseg (because those don't have just
type-generic operand, but also result) we have just keywords.