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Re: Register allocation issues
- From: dje at watson dot ibm dot com
- To: "Matt Lee" <reachmatt dot lee at gmail dot com>
- Cc: gcc at gcc dot gnu dot org
- Date: Thu, 6 Sep 2007 15:02:52 -0400
- Subject: Re: Register allocation issues
>>>>> Matt Lee writes:
Date: Thu, 06 Sep 2007 15:02:52 -0400
From: David Edelsohn <dje@watson.ibm.com>
Matt> There is no point trying to minimize usage of volatile hard registers,
Matt> is there? They are precisely there to be used up as much as needed.
Matt> The function is a leaf procedure as well, so there are no other
Matt> considerations. Lastly, architectures like PPC do make use of more
Matt> registers (without -frename-registers), so there has to be something
Matt> in the PPC back-end that allows for the liberal use or in mine that
Matt> prevents such.
GCC RA mostly is tuned for IA-32 with very few registers.
The rs6000 port defines the movmemsi pattern calling
expand_block_move() which generates many intermediate pseudos.
David