[Bug tree-optimization/106794] [13 Regression] ICE in vect_transform_slp_perm_load_1 since r13-2288-g61c4c989034548f4

["cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106794

--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The trunk branch has been updated by Richard Sandiford <rsandifo@gcc.gnu.org>:

https://gcc.gnu.org/g:1005c89431cc78a68762643e1bc7249c3959927e

commit r13-2738-g1005c89431cc78a68762643e1bc7249c3959927e
Author: Richard Sandiford <richard.sandiford@arm.com>
Date:   Tue Sep 20 15:27:47 2022 +0100

    vect: Fix SLP layout handling of masked loads [PR106794]

    PR106794 shows that I'd forgotten about masked loads when
    doing the SLP layout changes.  These loads can't currently
    be permuted independently of their mask input, so during
    construction they never get a load permutation.

    (If we did support permuting masked loads in future, the mask
    would need to be in the right order for the load, rather than in
    the order implied by the result of the permutation.  Since masked
    loads can't be partly or fully scalarised in the way that normal
    permuted loads can be, there's probably no benefit to fusing the
    permutation and the load.  Permutation after the fact is probably
    good enough.)

    gcc/
            PR tree-optimization/106794
            PR tree-optimization/106914
            * tree-vect-slp.cc (vect_optimize_slp_pass::internal_node_cost):
            Only consider loads that already have a permutation.
            (vect_optimize_slp_pass::start_choosing_layouts): Assert that
            loads with permutations are leaf nodes.  Prevent any kind of
grouped
            access from changing layout if it doesn't have a load permutation.

    gcc/testsuite/
            * gcc.dg/vect/pr106914.c: New test.
            * g++.dg/vect/pr106794.cc: Likewise.