tree-optimization/110614 - SLP splat and re-align (optimized)

The following properly guards the re-align (optimized) paths used
on old power CPUs for the added case of SLP splats from non-grouped
loads.  Testcases are existing in dg-torture.

Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.

	PR tree-optimization/110614
	* tree-vect-data-refs.cc (vect_supportable_dr_alignment):
	SLP splats are not suitable for re-align ops.

gcc/tree-vect-data-refs.cc

@@ -6815,10 +6815,11 @@ vect_supportable_dr_alignment (vec_info *vinfo, dr_vec_info *dr_info,
 	     same alignment, instead it depends on the SLP group size.  */
 	  if (loop_vinfo
 	      && STMT_SLP_TYPE (stmt_info)
-	      && !multiple_p (LOOP_VINFO_VECT_FACTOR (loop_vinfo)
-			      * (DR_GROUP_SIZE
-				 (DR_GROUP_FIRST_ELEMENT (stmt_info))),
-			      TYPE_VECTOR_SUBPARTS (vectype)))
+	      && (!STMT_VINFO_GROUPED_ACCESS (stmt_info)
+		  || !multiple_p (LOOP_VINFO_VECT_FACTOR (loop_vinfo)
+				  * (DR_GROUP_SIZE
+				       (DR_GROUP_FIRST_ELEMENT (stmt_info))),
+				  TYPE_VECTOR_SUBPARTS (vectype))))
 	    ;
 	  else if (!loop_vinfo
 		   || (nested_in_vect_loop