Re: Delay branch scheduling vs. the CFG

[Jeffrey A Law <law at redhat dot com>]

On Sun, 2005-11-13 at 22:20 +0100, Steven Bosscher wrote:
> On Sunday 13 November 2005 22:02, Jeffrey A Law wrote:
> > No great insights on how to make dbr_schedule CFG aware -- just
> > remember that a filled delay slot can represent 3 different cases:
> >
> >   1. An extension of the block containing the sequence.
> >
> >   2. An extension of the block at the target of a branch.
> >
> >   3. An extension of the fall-thru block.
> >
> >   4. An entirely new basic block on its own.
> 
> When can option 4 happen??
IIRC it occurs when there was only 1 insn in either the target
or fall-thru block.    When it gets sucked into the delay
slot of a branch, then it is effectively its own basic
block.

Or something along those lines -- it's been about 15 years since
I've had to reconstruct CFGs from PA assembly code and branch
traces ;)


jeff