This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: Exploiting dual mode operation
- From: Leehod Baruch <LEEHOD at il dot ibm dot com>
- To: Joern Rennecke <joern dot rennecke at superh dot com>
- Cc: gcc at gcc dot gnu dot org, Mircea Namolaru <NAMOLARU at il dot ibm dot com>
- Date: Thu, 22 Apr 2004 16:33:45 +0300
- Subject: Re: Exploiting dual mode operation
Hello,
Thank you for your message.
We see redundant sign extension removal as a partial
redundancy problem. This will give us not only the redundant
sign extensions, but also better placement for the
remaining ones. As a result sign extension instructions
may be moved and instructions that uses the highpart
may be replaced with others that doesn't use it.
This is not equivalent with live information for the highest
part of the registers.
Our approach will not require changes in the description file
(which in our opinion is a major problem with your code) and will
limit the changes to much fewer files.
Leehod and Mircea
Joern Rennecke <joern.rennecke@superh.com>
21/04/2004 09:26 PM
To: Mircea Namolaru/Haifa/IBM@IBMIL
cc: gcc@gcc.gnu.org, Leehod Baruch/Haifa/IBM@IBMIL
Subject: Re: Exploiting dual mode operation
> We are working on an optimization for eliminating redundant sign
extension
> instructions by making use of this duality. Currently this is done only
in
> very
> simple cases.
I have already submitted a patch for this:
http://gcc.gnu.org/ml/gcc-patches/2004-01/msg03259.html
It is still waiting for review.