llvm dev - Jan 2015 - [LLVMdev] Making a CopyToReg/CopyFromReg into a zext/sext?

I have a CopyToReg that is copying from different size types, what's the
best way to change that to a zext or sext node based on signed or unsigned?

I'm fairly unfamiliar with SelectionDAG process (outside of the docs on
llvm website).

It seems like I should be able to insert a custom hook using the register
class to identify the type, potentially in ISelDAGToDag.cpp or is there a
better place for this to be done?

Thanks.
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20150127/4f69073d/attachment.html>

On 01/27/2015 12:16 PM, Ryan Taylor wrote:
> I have a CopyToReg that is copying from different size types, what's 
> the best way to change that to a zext or sext node based on signed or 
> unsigned?
>
> I'm fairly unfamiliar with SelectionDAG process (outside of the docs 
> on llvm website).
>
> It seems like I should be able to insert a custom hook using the 
> register class to identify the type, potentially in ISelDAGToDag.cpp 
> or is there a better place for this to be done?
>
> Thanks.
>
It sounds to me like you are looking for the AssertSext / AssertZext nodes

-Matt
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20150127/7eb003f4/attachment.html>

Thanks for getting back to me.

So those nodes record if the type has already been expanded from a narrower
type. Can you elaborate how I could use these to help? Again, I'm pretty
unfamiliar with the SDNodes.

Thanks.

On Tue, Jan 27, 2015 at 3:22 PM, Matt Arsenault <Matthew.Arsenault at
amd.com>
wrote:
>  On 01/27/2015 12:16 PM, Ryan Taylor wrote:
>
>  I have a CopyToReg that is copying from different size types, what's
the
> best way to change that to a zext or sext node based on signed or unsigned?
>
>  I'm fairly unfamiliar with SelectionDAG process (outside of the docs
on
> llvm website).
>
>  It seems like I should be able to insert a custom hook using the
> register class to identify the type, potentially in ISelDAGToDag.cpp or is
> there a better place for this to be done?
>
>  Thanks.
>
>
> It sounds to me like you are looking for the AssertSext / AssertZext nodes
>
> -Matt
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20150127/5e0b18d4/attachment.html>