https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64379
Ramana Radhakrishnan <ramana at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P3 |P4
Status|UNCONFIRMED |NEW
Last reconfirmed| |2015-01-13
CC| |ramana at gcc dot gnu.org
Ever confirmed|0 |1
--- Comment #8 from Ramana Radhakrishnan <ramana at gcc dot gnu.org> ---
(In reply to Donn Seeley from comment #7)
> Re -mapcs-frame: Yes, the failure is due to code in
> arm_expand_epilogue_apcs_frame() that explicitly requires / stomps on IP in
> order to restore VFP/NEON registers. Sorry, I should have mentioned that.
> The indirect tailcall register is chosen from CALLER_SAVE_REGS via the "Cs"
> constraint, and CALLER_SAVE_REGS contains the arg regs plus IP; if the arg
> regs are in use, then the tailcall register ends up being IP. Hence the
> conflict.
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, I do wonder
if the fix here is to just turn IP regnum into a fixed register in the presence
of mapcs-frame.
regards
Ramana
