This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: Update: reload register allocation patch
- To: Joern Rennecke <amylaar at cygnus dot co dot uk>
- Subject: Re: Update: reload register allocation patch
- From: Bernd Schmidt <bernds at pathia dot cygnus dot co dot uk>
- Date: Sat, 27 Nov 1999 16:10:57 +0000 (GMT)
- cc: gcc-patches at gcc dot gnu dot org
On Tue, 23 Nov 1999, Joern Rennecke wrote:
> However, when I look at the code that sets spill_cost and spill_add_cost,
> I see that you don't take the width of the spilled register into account.
> The more hard register are allocated to a pseudo, the more expensive it
> is to spill it, since usually you have to reload all the hard registers
> of the pseudo.
Good point. I don't think the current code takes this into account either,
though.
> Or does it turn out to be advantagous to be a little more mean to multi-
> hard-reg pseudos because that frees up multiple spill registers at once?
No idea. I'll experiment a little. The obvious way to adjust the cost would
be to multiply by nregs; do you have any other ideas how to tune it?
Bernd