combine two load insns

[Frédéric RISS]

Le mardi 07 décembre 2010 à 06:18 -0700, Jeff Law a écrit :
> On 12/06/10 15:07, Ian Lance Taylor wrote:
> Given the two loads don't have a def-use data dependency combine won't 
> ever get the opportunity to do anything with them.  In general there is 
> no pass which combines insns without a true data dependency and targets 
> which have such insns have had to handle those combinations in machine 
> dependent reorg.  In fact, it was the combination of independent insns 
> which led to the introduction of the machine dependent reorg pass eons ago.

The issue with this approach is that reorg runs very late. I suppose
that if one wants to combine 2 SI loads into a DI load, it needs to be
done before IRA to satisfy the generated register constraints.

Fred