https://gcc.gnu.org/bugzilla/show_bug.cgi?id=37021 Bug 37021 depends on bug 56766, which changed state.
Bug 56766 Summary: Fails to combine (vec_select (vec_concat ...)) to (vec_merge ...) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56766 What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution|--- |FIXED