Bernd Schmidt <ber...@codesourcery.com> writes:
> I have added support for this to haifa-sched.c. I expect the question
> "why not use SMS" to come up; there were a number of reasons why I felt
> that code is unsuitable:
Fully agree that SMS is unsuitable here FWIW, but...
> There are (or were, when I started) some glaring weaknesses in SMS, such
> as giving up when the loop contains autoincrement addresses (which is
> the case in the example above), and by the looks of it fairly poor
> memory disambiguation compared to sched-ebb with cselib.
...I didn't see from an admittedly quick read of the patch how you
handle memory disambiguation between iterations. If a loop includes:
lb $3,($4)
sb $5,1($4)
then the two instructions can be reordered by normal ebb scheduling,
but the inter-iteration conflict is important for modulo scheduling.
Richard
