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Re: hard register reload patch
- To: law at cygnus dot com
- Subject: Re: hard register reload patch
- From: Joern Rennecke <amylaar at cygnus dot co dot uk>
- Date: Wed, 1 Dec 1999 03:11:27 +0000 (GMT)
- Cc: bernds at darkstar dot frop dot org, amylaar at cygnus dot co dot uk, gcc-patches at gcc dot gnu dot org
> > registers. Joerns patch is a step in that direction (combine_reloads goes
> > away).
> How related is this to your reload cleanup patch. It sounds like the same
> thing, and I've already agreed that we're going in the right direction.
> Continuing down this road seems like a reasonable thing to do.
But that aspecty can't be simply broken out - combine_reload reuses hard
registers that die. If you remove it without a replacement, register pressure
will increase, resulting in worse code and more reload aborts when it runs
out of spill registers.
By patch replaces the functionality of combine_reloads because registers that
die become available as spill registers, and the times they are not usable
are encoded in the hard reloads.