vect: ICE: in vectorizable_load, at tree-vect-stmts.c:9173 [PR94398]

vect: ICE: in vectorizable_load, at tree-vect-stmts.c:9173 [PR94398]

In the testcase for PR94398, we're trying to compute:

  alignment_support_scheme
    = vect_supportable_dr_alignment (first_dr_info, false);
  gcc_assert (alignment_support_scheme);

even for VMAT_GATHER_SCATTER, which always accesses individual elements.
Here we should set alignment_support_scheme to dr_unaligned_supported
the gather/scatter case instead of calling vect_supportable_dr_alignment.

2020-03-31  Felix Yang  <felix.yang@huawei.com>

gcc/
	PR tree-optimization/94398
	* tree-vect-stmts.c (vectorizable_store): Instead of calling
	vect_supportable_dr_alignment, set alignment_support_scheme to
	dr_unaligned_supported for gather-scatter accesses.
	(vectorizable_load): Likewise.

gcc/testsuite/
	PR tree-optimization/94398
	* gcc.target/aarch64/pr94398.c: New test.