• Matthias Braun's avatar
    cleanup special tarval and Unknown usage · af666143
    Matthias Braun authored
    This commit does:
    - Remove tarval_reachable+tarval_unreachable, dataflow analysis rather
      use top/bottom instead of other special values.
    - Rename tarval_undefined to tarval_unknown as it corresponds to the
      Unknown node (=a value which we don't know)
    - Remove predefined tarval_top/tarval_bottom from tv.h and place the
      defines into combo.c
    - Change compute_XXX constant folding functions to return tarval_unknown
      instead of tarval_bad if folding failed
    - compute_Unknown in combo results in tarval_bottom == tarval_unknown
      this eliminates strange special cases in the Cond/Switch rules and the
      now unnecessary cprop_X list.