[Bug c++/82209] Compile error "X causes a section type conflict with Y" should provide more information

["noloader at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82209

--- Comment #2 from Jeffrey Walton <noloader at gmail dot com> ---
(In reply to Eric Gallager from comment #1)
> Do you have a complete standalone testcase we could use to reproduce?

Thanks Eric.

We were not able to reduce it to a minimal test case. That was part of the pain
for us.

We found moving the dtor out-of-line fixed the problem. We have no idea why it
fixed the problem. Also see
https://github.com/weidai11/cryptopp/commit/51752cb91aa6.

We also have no idea what caused the problem. The issue was not present going
back one week earlier to commit 67bcdaed9abb. We did not twiddle with things
like section alignments or attributes.

The one thing that changed between now and then was adding Power8 AES through
built-ins. The major commits in the series can be found at
https://github.com/weidai11/cryptopp/issues/497. But there's nothing special
about the commits; they look like AESNI and ARMv8 intrinsics.

Maybe the Power8 AES built-ins caused GCC to take slightly different code
paths, and that knocked something loose?

It would still be nice to get a better message from the compiler when the error
surfaces. We dumb-lucked into the fix. We were trying anything we could think
of.