https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122569
--- Comment #6 from ptomsich at gcc dot gnu.org --- The test case from comment #3 is different (and I am still looking where this came from originally): it is a CTZ constant and uses the (value - (value >> 1)) expression to isolate the highest set bit after the or-cascade. In this case, the recognition on the clz_table_index pattern misses.
