This file tracks the status of the merger of the
"Introduce rtx subclasses" patches, and is slated for removal once all
are merged.

See https://gcc.gnu.org/ml/gcc-patches/2014-08/msg00498.html for more
information.

Phase 1: initial "scaffolding" commits:            DONE
Phase 2: per-file commits in main source dir:      DONE
Phase 3: per-file commits within "config" subdirs: DONE
Phase 4: removal of "scaffolding":                 IN PROGRESS
Phase 5: additional rtx_def subclasses:            TODO
Phase 6: use extra rtx_def subclasses:             TODO

TODO: "Scaffolding" to be removed
=================================
* DF_REF_INSN
* SET_BB_HEAD, SET_BB_END, SET_BB_HEADER, SET_BB_FOOTER
* SET_BB_NOTE_LIST
* SET_BND_TO
* SET_DEP_PRO, SET_DEP_CON
* SET_NEXT_INSN, SET_PREV_INSN
* SET_VINSN_INSN_RTX