https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114769
--- Comment #2 from Tamar Christina <tnfchris at gcc dot gnu.org> --- I believe this is safe, but the interface is definitely not the cleanest. vect_recog_absolute_difference has two callers: 1. vect_recog_sad_pattern where if you return true with unprom not set, then *half_type will be NULL. The call to vect_supportable_direct_optab_p will always reject it since there's no vector mode for NULL. Note that if looking at the dump files, the convention in the dump files have always been that we first indicate that a pattern could possibly be recognize and then check that it's supported. This change somewhat incorrectly makes the diagnostic message get printed for "invalid" patterns. 2. vect_recog_abd_pattern, where if half_type is NULL, it then uses diff_stmt to set them. So while the note in the dump file is misleading, the code is safe. I will however slightly refactor it to prevent the confusion.
