How can INITIAL_FRAME_POINTER_OFFSET be made correct?

[Dave Korn]

> -----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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