llvm dev - Aug 2014 - [LLVMdev] understanding DAG: node creation

I have an intrinsic and it must be lowered to instruction, which works with
fixed register.
So, it takes contents of this register and another argument as input. After
execution, the result of the instruction is placed into that same fixed
register.

What should I do in SelectionDAGBuilder::visitIntrinicCall to describe such
behaviour for a SDNode?

Thank you for the ideas and insights.
-- 
Sincerely,
Dmitri Kovalenko
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On Sun, Aug 31, 2014 at 01:18:38AM +0400, Dmitri Kovalenko
wrote:
> I have an intrinsic and it must be lowered to instruction, which works with
> fixed register.
> So, it takes contents of this register and another argument as input. After
> execution, the result of the instruction is placed into that same fixed
> register.
> 
> What should I do in SelectionDAGBuilder::visitIntrinicCall to describe such
> behaviour for a SDNode?
If this is a target specific intrinsic, you should custom lower it in
XXXTargetLowering::LowerOperation().  There are several examples of this
in lib/Target/

-Tom
> 
> Thank you for the ideas and insights.
> -- 
> Sincerely,
> Dmitri Kovalenko
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