This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: A Question About LRA/reload
- From: Kugan <kugan dot vivekanandarajah at linaro dot org>
- To: lin zuojian <manjian2006 at gmail dot com>, gcc at gcc dot gnu dot org
- Date: Tue, 09 Dec 2014 21:08:46 +1100
- Subject: Re: A Question About LRA/reload
- Authentication-results: sourceware.org; auth=none
- References: <20141209093747 dot GA25618 at ubuntu>
On 09/12/14 20:37, lin zuojian wrote:
> Hi,
> I have read ira/lra code for a while, but still fails to understand
> their relationship. The main question is why ira do color so early?
> lra pass will do the assignment anyway. Sorry if I mess up coloring
> and hard register assignment, but I think it's better to get job
> done after lra elimiation, inheriation, ...
IRA does the register allocation and LRA matches insn constraints.
Therefore IRA has to do the coloring. LRA, in the process matching
constraints may change some of these assignment. Please look at the
following links for more info.
https://ols.fedoraproject.org/GCC/Reprints-2007/makarov-reprint.pdf
https://gcc.gnu.org/wiki/cauldron2012?action=AttachFile&do=get&target=Local_Register_Allocator_Project_Detail.pdf
Thanks,
Kugan