[LLVMdev] understanding DAG: node creation

[Sam Parker]

Hi Dmitri,

If you have such a simple intrinsic which operates on a single register,  just lower the intrinsic to a target specific node which is only implemented by a single instruction. Like you were doing before and by using a chain operand. Hard code the instruction to use and define the global register and only pass the instruction the actual variable argument.

Hope that helps,
Sam

Sam Parker
Research Student
Electronic Systems Design Group
School of Electronic, Electrical and Systems Engineering
Loughborough University

----- Reply message -----
From: "Dmitri Kovalenko" <dmitri.a.kovalenko at gmail.com>
To: <llvmdev at cs.uiuc.edu>
Subject: [LLVMdev]  understanding DAG: node creation
Date: Sat, Aug 30, 2014 22:18

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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