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Re: CSE removing a load that is necessary

From: "Pranav Bhandarkar" <pranav dot bhandarkar at gmail dot com>
To: "Dave Korn" <dave dot korn at artimi dot com>
Cc: gcc at gcc dot gnu dot org
Date: Mon, 30 Jul 2007 16:07:54 +0530
Subject: Re: CSE removing a load that is necessary
References: <649555d50707271007p64000747tb6c003177e4ffe1d@mail.gmail.com> <m3lkd1220i.fsf@localhost.localdomain> <038201c7d235$6c41cde0$2e08a8c0@CAM.ARTIMI.COM>

Hi,

>   Or perhaps this could be another manifestation of the "cse gets confused by
> reg_equal notes on subparts of dimode pseudos if no movdi pattern is defined
> in the backend" bug[*]?  Pranav, is there a movdi pattern in your backend?
> There needs to be one, gcc does get it wrong if you rely on it to break
> everything down to si-sized movs.

Yes, It looks like a similar problem, but there seems to be no
consensus on a correct solution to this problem. I couldnt find the
bug number but  this thread describes the exact same problem ( but
with REG_EQUIV notes).

http://gcc.gnu.org/ml/gcc/2001-02/msg01372.html


Thanks,
Pranav

References:
- CSE removing a load that is necessary
  - From: Pranav Bhandarkar
- Re: CSE removing a load that is necessary
  - From: Ian Lance Taylor
- RE: CSE removing a load that is necessary
  - From: Dave Korn

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