[patch] Fix PR43464: update loop closed SSA form once copy prop is done

[Kenneth Zadeck]

On 03/24/2010 12:58 AM, Sebastian Pop wrote:
> On Tue, Mar 23, 2010 at 22:40, Kenneth Zadeck
> <Kenneth.Zadeck@naturalbridge.com> wrote:
>   
>> Let me try to bring some perspective back into this discussion,
>> because it is clear that this is getting out of hand.
>>
>> There are two solutions that must be considered: a short term one and
>> a long term one.
>>
>> At this stage, a rewrite of a pass of the compiler is not acceptable,
>> so calling that rewrite_into_closed_loop_ssa form in a place
>> immediately after the pass that messed it up is the correct short term
>> solution.  And it is purely Richard's call as to how careful that
>> patch needs to be about checking if things get messed up.
>>
>> However, I agree with Steven that this is a very poor long term
>> solution that should be strongly avoided.  Unswitching needs to be
>> more careful about the damage that it does to the representation.
>>     
> Ok, I stand corrected.
>
> I will work on getting all the patches necessary to maintain the
> LCSSA form during the LNO.  As this will take time and could
> introduce new errors, I will propose these changes only for 4.6.
>
> Sebastian
>   
thanks

kenny