Re: Add more supported primitives in libgccjit IR (was: Shrinking the C core)

[Alfred M. Szmidt]

   > Look at data.c:arith_driver.  You'll see that it's essentially a function 
   > which dispatches the handling of its arguments depending on their type...
   >
   > These integer/float/bignum types are not known at compilation time ...

   This is not correct. If you have something like
   (progn (setq x 1) (> x 2)), compiler is actually able to determine the
   type of X at compilation time.

It is absolutley correct, the Emacs compiler is not capable of doing
what you are suggesting.  There are no specific functions for fixnum
comparison in Emacs Lisp, nor is the Emacs Lisp compiler capable of
being instructed to do such specific things.  I've been repeating this
constantly now.  That is needed to make programs faster in Lisp.

The reason why SBCL is faster is because it allows individuals to
instruct the compiler to do what is best for the program -- e.g., the
org maintainers can write functions that are more specialized.  Native
compilation simply does not solve that!