RTL sharing bootstrap failure on sparc-sun-solaris2.10

Ian Lance Taylor iant@google.com
Thu Sep 6 19:25:00 GMT 2007


Jan Hubicka <jh@suse.cz> writes:

> > Jan Hubicka <hubicka@ucw.cz> writes:
> > 
> > > Producing USE expressions embedding whole INSN.  The comment promise
> > > that those will be removed before reorg ends, but they are not.  This
> > > patch just adds simple code to remove them in very last dbr_schedule
> > > pass. 
> > 
> > I see code in dbr_schedule to delete them:
> > 
> >   /* Delete any USE insns made by update_block; subsequent passes don't need
> >      them or know how to deal with them.  */
> >   for (insn = first; insn; insn = next)
> >     {
> >       next = NEXT_INSN (insn);
> > 
> >       if (NONJUMP_INSN_P (insn) && GET_CODE (PATTERN (insn)) == USE
> > 	  && INSN_P (XEXP (PATTERN (insn), 0)))
> > 	next = delete_related_insns (insn);
> >     }
> > 
> > Why is that not working?
> 
> Hmm, good catch. I didn't noticed that code.
> The problem is that update_block is still called after this loop is
> done, at least moving that loop down past the loop just bellow it solves
> the ICE too.

Ah, it's from the calls to fill_simple_delay_slots in
make_return_insns.  The "Delete any USE insns" loop needs to move
below that.

> I must admit I have no idea what those placeholders are good for...

They tell mark_target_live_regs that the registers used by the insn
which was moved are live.

Ian



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