Lack of documentation of CBLOCK's slots: GEN, IN, OUT.

[Tobias C. Rittweiler]

Pasting from compiler/node.lisp:

  (def!struct (cblock ...)
     ...

    ;; in constraint propagation: list of LAMBDA-VARs killed in this block
    ;; in copy propagation: list of killed TNs
    (kill nil)
    ;; other sets used in constraint propagation and/or copy propagation
    (gen nil)
    (in nil)
    (out nil)

    ...)

"other sets" is not very descriptive.

[Nikodemus Siivola (nikodemus)]

Documentation is always good...

I haven't actually checked, but these BLOCK-KILL should be the "semistandard" GEN, KILL, IN, and OUT sets from computer literature: exact meaning depends on the type of flow-analysis being run -- in our case either copy propagation or constraint propagation. Constraint propagation is less common, but any decent textbook should describe copy propagation.

[Nikodemus Siivola (nikodemus)]

s/these BLOCK-KILL/these and BLOCK-KILL/

[Douglas Katzman (dougk)]

and why not every other slot of every other structure? This request, while not "nonsense" is not worthy of being kept open.