[Bug lto/114505] static archives built with gcc --without-zstd cause ICE when read by gcc with zstd support

["eschwartz93 at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114505

--- Comment #12 from Eli Schwartz <eschwartz93 at gmail dot com> ---
(In reply to Xi Ruoyao from comment #1)
> Confirmed as I've seen it before.  At least we should turn it into a
> "normal" error message instead of ICE.
> 
> But note that even "downgrading the compression algorithm" is supported, it
> won't really help rolling-release distros.  When GCC itself is upgraded with
> a LTO API version change, all previous LTO static archives will be unusable
> anyway.  Generally the distros should not ship LTO static archives at all.

Agreed, figuring out how to solve that is an open ticket too:
https://bugs.gentoo.org/926120

Still would like to solve the zstd case :D especially since I am sure given the
flexibility of a from-source distro there will be users who insist they'd
rather rebuild the entire OS on a GCC upgrade, so reducing the compression
algorithm edge case will come in use.


(In reply to Andrew Pinski from comment #2)
> On the input side:
> Wait this should not happen.
> 
>       lto_end_uncompression (stream,
>                              file_data->lto_section_header.get_compression
> ());


I cannot swear this was the case but the error very specifically occurred as
part of a Gentoo profile change that caused zstd to be enabled.

The version of zstd should be the same, at least...