Re: [PATCH, take 2] Fix PR tree-optimization/49960 ,Fix self data dependence

[Jakub Jelinek <jakub at redhat dot com>]

On Mon, Nov 21, 2011 at 06:56:55PM +0200, Razya Ladelsky wrote:
> I have some non-affine cases for which compute_affine_dependence is called 
> (as it is called for 
> ALL dependences from compte_all_depepndences()), and no harm is done.
> I looked a little bit closer into the code, and this is what happens for 
> non affine accesses:
> 
> initialize_data_dependence_relation() assigns 
> DDR_ARE_DEPENDENT (res) = chrec_dont_know for the dr.

It can be chrec_known too (that's actually the only interesting case for us
unless it is a read-read ddr), but you're right that likely
object_address_invariant_in_loop_p should be false.

> Then, compute_affine_depepndence()
> tests if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE), and does nothing 
> otherwise.
> Since the dr was initialized with chrec_dont_know, no harm is done.
> 
> Anyway, since it is useless for your gather case, I'll just remove it, 
> along with compute_self_dependence().
> 
> OK?

Yes, patch preapproved.

	Jakub