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[Bug tree-optimization/68707] [6 Regression] testcase gcc.dg/vect/O3-pr36098.c vectorized using VEC_PERM_EXPR rather than VEC_LOAD_LANES
- From: "rguenther at suse dot de" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 08 Dec 2015 14:29:26 +0000
- Subject: [Bug tree-optimization/68707] [6 Regression] testcase gcc.dg/vect/O3-pr36098.c vectorized using VEC_PERM_EXPR rather than VEC_LOAD_LANES
- Auto-submitted: auto-generated
- References: <bug-68707-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68707
--- Comment #7 from rguenther at suse dot de <rguenther at suse dot de> ---
On Tue, 8 Dec 2015, alalaw01 at gcc dot gnu.org wrote:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68707
>
> --- Comment #6 from alalaw01 at gcc dot gnu.org ---
> Well, I can confirm that the patch generates load-lanes/store-lanes instead of
> SLP, all over the (vect) testsuite. All execution tests are passing :) so it
> *may* just be a case of updating a lot of scan-tree-dump tests but we'll need
> to do at least some performance evaluation, watch this space.
Eh ;) From discussion on IRC it seems that we should retain SLP
if the SLP code wouldn't need any permutation (and then we can also
include some special-casing of very low-trip loops). I'll update the patch
tomorrow also trying to handle the interleaving case (to make testing
effects on my side easier).