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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libffi/102923] [12 Regression] powerpc64 (BE) linux all languages bootstrap broken after libffi 3.4.2 import.
Date: Mon, 25 Oct 2021 15:59:20 +0000 [thread overview]
Message-ID: <bug-102923-4-QV5EnZqft4@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-102923-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102923
--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Segher Boessenkool from comment #4)
> > At least in linux64_closure.S, perhaps guarding it with #ifdef __VEC__ might
> > be ok, because the C code will not use that code if __VEC__ isn't defined:
> > #elif !defined(__VEC__)
> > /* If compiled without vector register support (used by assembly)... */
> > if ((cif->abi & FFI_LINUX_LONG_DOUBLE_IEEE128) != 0)
> > return FFI_BAD_ABI;
> > But not sure about linux64.S if it doesn't suffer from the same problem.
>
> Note that __VEC__ does not mean the current CPU can execute those insns,
> of course, so these #ifdefs are only good if you compile this file twice,
> or similar?
Sure. I think the expectation is that one gets the ieee128 long double support
in libffi only if libffi is built with -mcpu=power8 (or -mcpu=power7 or -mvsx).
And the assumption is that the *.S files are compiled with the same
-mcpu=/-mvsx flags as the C files.
So the only question is if all the lvx/stvx instructions are in code path that
will not be reached when __VEC__ support isn't seen on the C side.
The whole inital patch is:
https://github.com/libffi/libffi/commit/73dd43afc8a447ba98ea02e9aad4c6898dc77fb0
next prev parent reply other threads:[~2021-10-25 15:59 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-25 8:45 [Bug bootstrap/102923] New: " iains at gcc dot gnu.org
2021-10-25 8:52 ` [Bug bootstrap/102923] " rguenth at gcc dot gnu.org
2021-10-25 9:08 ` jakub at gcc dot gnu.org
2021-10-25 9:11 ` iains at gcc dot gnu.org
2021-10-25 13:07 ` [Bug libffi/102923] " hjl.tools at gmail dot com
2021-10-25 15:50 ` segher at gcc dot gnu.org
2021-10-25 15:59 ` jakub at gcc dot gnu.org [this message]
2021-10-25 17:07 ` hjl.tools at gmail dot com
2021-10-25 17:11 ` hjl.tools at gmail dot com
2021-10-25 21:28 ` segher at gcc dot gnu.org
2021-12-29 15:36 ` jakub at gcc dot gnu.org
2021-12-29 19:46 ` segher at gcc dot gnu.org
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