vect: Adjust vectorizable_load costing on VMAT_CONTIGUOUS_PERMUTE

This patch adjusts the cost handling on
VMAT_CONTIGUOUS_PERMUTE in function vectorizable_load.  We
don't call function vect_model_load_cost for it any more.

As the affected test case gcc.target/i386/pr70021.c shows,
the previous costing can under-cost the total generated
vector loads as for VMAT_CONTIGUOUS_PERMUTE function
vect_model_load_cost doesn't consider the group size which
is considered as vec_num during the transformation.

This patch makes the count of vector load in costing become
consistent with what we generates during the transformation.
To be more specific, for the given test case, for memory
access b[i_20], it costed for 2 vector loads before,
with this patch it costs 8 instead, it matches the final
count of generated vector loads basing from b.  This costing
change makes cost model analysis feel it's not profitable
to vectorize the first loop, so this patch adjusts the test
case without vect cost model any more.

But note that this test case also exposes something we can
improve further is that although the number of vector
permutation what we costed and generated are consistent,
but DCE can further optimize some unused permutation out,
it would be good if we can predict that and generate only
those necessary permutations.

gcc/ChangeLog:

	* tree-vect-stmts.cc (vect_model_load_cost): Assert this function only
	handle memory_access_type VMAT_CONTIGUOUS, remove some
	VMAT_CONTIGUOUS_PERMUTE related handlings.
	(vectorizable_load): Adjust the cost handling on VMAT_CONTIGUOUS_PERMUTE
	without calling vect_model_load_cost.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/pr70021.c: Adjust with -fno-vect-cost-model.

0 files changed, 0 insertions, 0 deletions