Re: [PATCH] Fix IVOPTs problem

[Jeffrey A Law <law at redhat dot com>]

On Thu, 2005-08-25 at 10:48 +0200, Richard Guenther wrote:

> 
> I think we cannot avoid loosing aliasing precision without directly
> storing the necessary information to re-construct aliasing information
> at get_tmr_operands time.
It certainly needs to be stored in the TARGET_MEM_REF expression, I
don't know when the best time to record this information will be.

So I think we have a few questions we need to answer, some are
shorter term, some are long term.

First, for 4.1, do we think we can get into similar situation where
IVOPTs changes the computed aliasing information, but without the
patch to muck around with ARRAY_REFs?  If so, then we need a simple
and safe solution for 4.1.


Second, for 4.2 and beyond, do we want to first ensure that we
can attach the aliasing information to the TARGET_MEM_REF and 
make that a prerequisite for the ARRAY_REF patch?

Or do we want to go with a simple solution, then install the
ARRAY_REF patch, then work on carrying the aliasing information
in the TARGET_MEM_REF expression.

I've got no strong opinions on how we want to deal with this
for 4.2, mostly because I haven't thought through how much
work it will be to carry all the aliasing information on the
TARGET_MEM_REF and use that in the operand scanning code.

jeff