https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111231
--- Comment #29 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
Sorry, I was looking at the wrong pair of insns. The earlier store to that
location was insn 111.
111: [r212:SI (1 MEM[(struct Vec128 *)_179]+0 S4 A64)] = {r0:SI..r3:SI}
It appears that the problem is a disagreement between alias_set_subset_of ()
and alias_sets_conflict_p(). The former thinks sets 1 and 2 have a permissible
subset relationship (2 is a subset of 1), so removes the later store during
postreload. The latter is then used by alias_sets_conflict_p which thinks
there is no conflict between the two sets and fails to add a scheduling
dependency before sched2.
