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Date: Thu, 20 Nov 2014 13:38:00 -0000
From: Richard Biener <rguenther@suse.de>
To: Bernd Schmidt <bernds_cb1@t-online.de>
cc: Jan Hubicka <hubicka@ucw.cz>, gcc-patches@gcc.gnu.org,     "Joseph S. Myers" <joseph@codesourcery.com>,     Thomas Schwinge <thomas_schwinge@mentor.com>,     Julian Brown <julian@codesourcery.com>,     Cesar Philippidis <cesar_philippidis@mentor.com>
Subject: Re: LTO streaming of TARGET_OPTIMIZE_NODE
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References: <20141113040652.GB1984@kam.mff.cuni.cz> <546DDE1C.6060203@t-online.de>
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On Thu, 20 Nov 2014, Bernd Schmidt wrote:

> On 11/13/2014 05:06 AM, Jan Hubicka wrote:
> > this patch adds infrastructure for proper streaming and merging of
> > TREE_TARGET_OPTION.
> 
> This breaks the offloading path via LTO since it introduces an incompatibility
> in LTO format between host and offload machine.
> 
> A very quick patch to fix it is below - the OpenACC testcase I was using seems
> to be working again with this. Thoughts, suggestions?

The offload target needs to have the same target options as the host?

Are the offload functions marked somehow?  That is, can we avoid
setting TREE_TARGET_OPTION on them?  Or rather we need to have a
default TREE_TARGET_OPTION node for the offload target which we'd
need to set - how would you otherwise transfer different offload
target options to the offload compile?  How do you transfer
offload target options to the offload compile at all?

I think this just shows conceptual issues with the LTO approach...

Thanks,
Richard.