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Re: Register allocation trouble


Thanks to all those who replied. :-)

Here's what I've done to fix the problem:

1. Set the base rclass to A only.

2. Configured secondary reloads to B via A.

3. Disabled the Rb constraint. [*]

That's enough to create correct code, but it's pretty horrible, so I also added new patterns of the form Nathan suggested so that the base register can be allocated directly, as an optimization. These occur before the main mov insn in the search order, and catch only valid MEMs that won't get meddled with, so I believe that the "one mov per mode" rule can be safely ignored. The main mov pattern can still do the loads/stores, via the secondary reloads, so I believe that to be safe too.

Thanks again

Andrew

[*] I've not removed it because actually it's still active for some address spaces, but that's a detail I glossed over previously.


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