Re: Shrinking the C core

[Alfred M. Szmidt]

   >    Then, what does GCC do? AFAIK, GCC JIT takes the Elisp byte code,
   >    transforms it into JIT pseudocode, and optimizes the actual code flow.
   >
   > What does GCC do _WHERE_?  What backend? What language? You're
   > speaking in such broad terms that it makes it impossible to continue
   > this discussion.  I don't know how the native compilation works, but
   > no matter what you feed to GCC it cannot do magic and any optimization
   > should be done on what the Emacs compiler does.

   Native compilation provides the necessary information about Elisp to GCC.

Native compilation provides nothing of the sort.

   Otherwise, native compilation would be useless.

Native compilation removes the indirection of going through the VM,
that is a useful step.  It also provides the JIT.

SBCL does transformation of Lisp code, there is a huge difference
there that clearly is being ignored here.

   > That is the type of information SBCL knows about, or allows the user
   > to specify.  Emacs does not have that today, and that incures one set
   > of overhead.  There are plenty more...

   AFAIK, users cannot specify type info manually, but types are tracked
   when transforming Elisp byte code into LIMP representation.

You cannot track type information in a dynamically typed language
without providing hints, something Emacs lisp does not do.