https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91453
--- Comment #2 from Uroš Bizjak <ubizjak at gmail dot com> --- Latest SVN creates the following RTX in _.ira dump: (insn 144 12 145 2 (set (subreg:V2DI (reg:DI 161) 0) (vec_merge:V2DI (vec_duplicate:V2DI (reg:DI 111 [ ubound.0 ])) (const_vector:V2DI [ (const_int 0 [0]) repeated x2 ]) (const_int 1 [0x1]))) "deferred_character_23.f90":27:0 -1 (nil)) This is suspiciously close to PR91454. "-1" hints at unknown insn.