replacing the backwards threader and more

Jeff Law jeffreyalaw@gmail.com
Tue Jun 15 04:03:37 GMT 2021



On 6/14/2021 12:40 AM, Richard Biener wrote:
>
>> I bet it's going to be tougher to remove DOM's threader.  It knows how
>> to do thinks like resolve memory references using temporary equivalences
>> and such.  But I bet it's enough to drop the VRP based threaders.
> Yes.  In fact I am wondering if adding threading to the not iterating FRE
> would make it possible to drop DOM, replacing it with instances of FRE.
I'd think so.  I'd approach as:

1. Remove the VRP threader instances.
2. Drop cprop and redundancy elimination from DOM using FRE instead
3. What's left of DOM is just forward jump threading.  Revamp & 
simplify.  Then either make it a distinct pass or as a sub-pass of FRE.

But one could just as easily look at adding threading to FRE and just 
killing DOM and its jump threading.

Jeff



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