m68k bootstrapping broken

[Jim Wilson]

Andreas Schwab wrote:
> I sometimes get bootstrap failures on ia64, and the one and only
> difference between stage2 and stage3 is two insns being swapped in a
> single object file without any semantic change.  Those failures go away
> when changing the environment in any way, and because of that I was unable
> to debug that yet.

There is a known problem with the scheduler's use of cselib.  This only 
happens on IA-64, because only IA-64 uses the sched-ebb.c file which 
enables use of cselib.

The problem is that the scheduler calls cselib, stores data returned 
from cselib in scheduler data structures, cselib frees the data when it 
doesn't need it anymore, and then the scheduler dereferences the 
already-freed data getting garbage.

There was a long discussion about this a few months ago, but it didn't 
come to any resolution.  It was either Jakub or Jan that tracked down 
the problem to the scheduler's use of cselib.  I think it was HJ that 
reported the initial bootstrapping bug.

I've never seen this problem on my machine.
-- 
Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com