Re: [PATCH] Fix PR62283

["H.J. Lu" <hjl.tools@gmail.com>]

On Tue, Apr 28, 2015 at 1:29 AM, Richard Biener <rguenther@suse.de> wrote:
>
> The following fixes a missed optimization in basic-block vectorization.
> Currently we require the SLP chain to end up in a sequence of loads
> we support.  But of course we can in theory end the SLP chain at
> any point and simply construct the vector operand of the uses by
> pieces.  This is what the patch does to handle the case where
> "external" defs are not really external.  As the patch is somewhat
> more generic it also handles more cases and relies on the cost model
> to reject the outright non-profitable ones (like the bb-slp-14.c
> case which is run with -fno-vect-cost-model though).
>
> Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
>
> Richard.
>
> 2015-04-28  Richard Biener  <rguenther@suse.de>
>
>         PR tree-optimization/62283
>         * tree-vect-slp.c (vect_build_slp_tree): When the SLP build
>         fails fatally and we are vectorizing a basic-block simply
>         cause the child to be constructed piecewise.
>         (vect_analyze_slp_cost_1): Adjust.
>         (vect_detect_hybrid_slp_stmts): Likewise.
>         (vect_bb_slp_scalar_cost): Likewise.
>         (vect_get_constant_vectors): For piecewise constructed
>         constants place them after the last def.
>         (vect_get_slp_defs): Adjust.
>         * tree-vect-stmts.c (vect_is_simple_use): Detect in-BB
>         externals for basic-block vectorization.
>

This caused:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65935


-- 
H.J.