[lto][patch] Use decl uid instead of node uid in ipa-pure-const

[Jan Hubicka]

> > Ah, but it should not change nodes ids, it is simply resusing dead IDs
> > for new nodes. If it changes IDs on LTO, then something is wrong.
> 
> I am sorry that I don't remember the details, but I think what was
> happening was something like
> 
> * A node with id 42 is created
> * We (LTO) remember something about the node
> * That node is removed

When node is removed, the node removal hook is called that should
release the data.  So it looks like bug is caused removing node w/o
calling the removal hook.  I will revert the patch and look into it.

Honza
> * A new node with id 42 is created
> * LTO gets confused
> 
> As Diego noticed, the clone infrastructure changed and the patch might
> not be necessary any more. What I would suggest is to revert it a tree
> and see if libgomp.c++/for-4.C still works. If it does, just remove
> the patch for real and continue with the merge.
> 
> Cheers,
> -- 
> Rafael Avila de Espindola
> 
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