tree-optimization/112404 - two issues with SLP of .MASK_LOAD
The following fixes an oversight in vect_check_scalar_mask when
the mask is external or constant. When doing BB vectorization
we need to provide a group_size, best via an overload accepting
the SLP node as argument.
When fixed we then run into the issue that we have not analyzed
alignment of the .MASK_LOADs because they were not identified
as loads by vect_gather_slp_loads. Fixed by reworking the
detection.
PR tree-optimization/112404
* tree-vectorizer.h (get_mask_type_for_scalar_type): Declare
overload with SLP node argument.
* tree-vect-stmts.cc (get_mask_type_for_scalar_type): Implement it.
(vect_check_scalar_mask): Use it.
* tree-vect-slp.cc (vect_gather_slp_loads): Properly identify
loads also for nodes with children, like .MASK_LOAD.
* tree-vect-loop.cc (vect_analyze_loop_2): Look at the
representative for load nodes and check whether it is a grouped
access before looking for load-lanes support.
* gfortran.dg/pr112404.f90: New testcase.