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Re: Commit: RL78: Include tree-pass.h


> But we should definitely have a way to register machine dependent
> passes, and what's wrong with the plugin interface?

IIRC I asked about how to schedule that pass when I wrote it, and "use
the plugin API" was the recommendation.

Some background...

The RL78 devirtualization pass is *not* a reorg pass, it has to happen
after reload but before debug info is set up.  The RL78 does not have
a consistent register set or addressing scheme, GCC cannot practically
support it.  So RL78 uses a virtual register set and machine
description until after reload, then copy data in and out of the
virtual registers to physical registers depending on the operations
required.  The only way to get decent performance and reasonable
debugging is to do that pass as soon after reload as possible, so the
remaining optimizations can work with real registers.

Basically, after the RL78 devirtualization pass, the RL78 is a
completely different target machine.


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