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Re: RFD, draft patch: IRA costs for reg_equiv_invariant regs
- From: Vladimir Makarov <vmakarov at redhat dot com>
- To: Jeff Law <law at redhat dot com>
- Cc: Bernd Schmidt <bernds at codesourcery dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>, Maxim Kuvyrkov <maxim at codesourcery dot com>
- Date: Wed, 02 Jun 2010 17:05:17 -0400
- Subject: Re: RFD, draft patch: IRA costs for reg_equiv_invariant regs
- References: <4BE46C12.6090206@codesourcery.com> <4BEC8539.5030804@redhat.com> <4C06851A.6040608@codesourcery.com> <4C06AE45.1040305@redhat.com> <4C06BF71.20209@redhat.com>
Jeff Law wrote:
On 06/02/10 13:17, Vladimir Makarov wrote:
Bernd Schmidt wrote:
On a not-quite-unrelated note, in the 2004 GCC summit proceedings you
write that you had implemented rematerialization. Do you still have
the
patch?
Here some code I found. It is very old I have no idea its state but
it is enough to get an idea about rematerlization between RA and
reload. IMHO, that is where rematerialization should be implemented
(reload is another place but it could make reload even more
complicated). We discussed it recently with Maxim and I am CCing him
too.
I would strongly discourage handling rematerialization in reload.
Ideally work on rematerialization would dovetail with my own to split
ranges. ie, when an expression is rematerialized, do so into a new
pseudo/allocno which is then allocated by the existing ira allocation
callbacks.
Right. It is really worth for Bernd and Maxim to look at your branch
reload-v2.