[LLVMdev] Re: InstructionSelectBasicBlock question

[Chris Lattner]

On Thu, 2 Mar 2006, Vladimir Prus wrote:
>>     stack, so these hacks are worthwhile.  The IA64 presumably copied the
>>     implementation from the PPC backend).
>
> Let me make sure I understand: the hacks are to reduce stack space of the
> *instruction selector*? So, if I use PPC codegen on darwin/ppc, things will
> work, but if I use X86 codegen on the same darwin/ppc machine, X86 won't
> use those stack-space reducing hacks and stack with blow up?

Yes, exactly.

>> To me, I think it would make sense to move the implementation in the PPC
>> backend up to the SelectionDAGISel class.  The stack space reducing hacks
>> can benefit all targets, and the algorithm is the same for all (like you
>> said, except for the enum).  The X86 backend can override it, explicitly
>> call the superclass, then do the magic it wants.
>
> To clarify, the base method should have implementation and should not be
> pure, right?

Correct.

>> Would you be interested in working on this?
>
> Yes, I hope to do this in near future.

Great!

-Chris

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