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[Bug target/64379] VFP register restore in ARM epilogue can break indirect tailcalls
- From: "ebotcazou at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 13 Jan 2015 16:05:32 +0000
- Subject: [Bug target/64379] VFP register restore in ARM epilogue can break indirect tailcalls
- Auto-submitted: auto-generated
- References: <bug-64379-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64379
Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |ebotcazou at gcc dot gnu.org
--- Comment #9 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
> Uggh - these ancient options in the backend. mapcs-frame is quite ancient
> and isn't really something that's tested very often, no wonder it's rotting.
> In this case we seem to have regressed something that worked earlier,
Yes, indirect tailcalls used to be rejected by the back-end.
> I do wonder if the fix here is to just turn IP regnum into a fixed register in
> the presence of mapcs-frame.
This would only turn the problem into an ICE here. I think this needs to be
fixed in arm_function_ok_for_sibcall, either in a big-hammer-ish way (disable
again indirect tailcalls with -mapcs-frame) or in a more precise way.