Re: kgr: dealing with optimalizations? (was Re: [RFC 06/16] kgr: add Documentat)ion

From: Michael Matz
Date: Fri May 09 2014 - 08:22:58 EST


Hi,

On Fri, 9 May 2014, Pavel Machek wrote:

> Ok, one big question: you are replacing single functions, and assume
> that's ok, right?
>
> But ... is it ok? gcc is allowed to do optimalization on whole source
> file (and whole source tree with LTO). How do you prevent situation
> where changing function foo() breaks optimalization in function bar()?

If such situation (behaviour changes with optimization) happens it's
either compiler or a source bug, so is of no direct concern to kgraft.
If you want to exchange an inlined function foo you of course have to take
care of actually exchanging all functions into which foo was inlined.
For that you need the inline tree for all kernels for which you want to
support kgrafting.

> Is turning off inter-procedural and inter-module optimalizations needed
> for kgraft to work?

No.


Ciao,
Michael.
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