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From: "lhyatt at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug lto/106274] Loss of macro tracking information with -flto
Date: Wed, 13 Jul 2022 12:13:38 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D106274

--- Comment #3 from Lewis Hyatt <lhyatt at gcc dot gnu.org> ---
(In reply to Martin Li=C5=A1ka from comment #2)
> I think it's a dup of PR80922.

I think it's a bit different, if I understand correctly, PR80922 is asking =
for
something much more difficult, it wants the LTO streaming process to be abl=
e to
remember that it saw a diagnostic pragma, so that the LTO frontend can know
about it when reading the data back in, and so suppress new warnings it is =
able
to generate due to the power of the interprocedural analysis it has access =
to.
That seems pretty challenging, given we still have a lot of bugs with just
handling diagnostic pragmas properly in the non-LTO case.

In my testcase here, the diagnostic is emitted by cc1/cc1plus while produci=
ng
the data for LTO, not by the LTO frontend, and everything is fine with it
except that it gets printed with a barebones printer, rather than a virtual
location aware printer.=