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RE: How can INITIAL_FRAME_POINTER_OFFSET be made correct?
- From: "Dave Korn" <dk at artimi dot com>
- To: "'Joern Rennecke'" <joern dot rennecke at superh dot com>
- Cc: <gcc at gcc dot gnu dot org>
- Date: Fri, 19 Mar 2004 17:54:47 -0000
- Subject: RE: How can INITIAL_FRAME_POINTER_OFFSET be made correct?
> -----Original Message-----
> From: Joern Rennecke
> Sent: 19 March 2004 17:24
> If you mention LINK_REGS in EPILOGUE_USES, you'll have to
> assume that it is always 'used', and use REG_N_SETS to check
> if it's clobbered.
Hmmm, actually there's no definition for EPILOGUE_USES at all, despite the
fact that it does actually use LINK_REGNUM. Dunno if that's really a
problem or not. It *is* marked as a CALL_USED register.
> Otherwise, I'd suggest setting a watchpoint to find out where
> exactly regs_ever_live[LINK_REGS] is set.
Yeh, I guess that'll give me the definitive answer. I was kinda hoping
that someone would be able to give me a definite answer about the scope of
validity of regs_ever_live, such as "It's only guaranteed to be completely
up-to-date by the time emit_prologue is called".
ISTM that it would be very bad of the docs to suggest using regs_ever_live
at a time when the information in it was incorrect or incomplete, but maybe
it's not meant to change after IFPO and it's just a bug that is causing the
inconsistency.
cheers,
DaveK
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