Hi !
Consider the following file to be compiled:
(declaim (optimize (speed 3)
(compilation-speed 0)
(safety 0)
(debug 0)))
(defun assign (array value)
(declare (type (simple-array fixnum (* *)) array))
(declare (type fixnum value))
(let ((size (array-dimension array 0))) ; don't worry, array is square
(dotimes (i size)
(declare (type fixnum i))
(dotimes (j size)
(setf (aref array i j) value)))))
The declaration of i as a fixnum seems to allow CMU-CL to inline some
operations on the loop. Otherwise, I would get a message liike this:
; In: DEFUN ASSIGN
; (DOTIMES (I SIZE) (DOTIMES # #))
; --> DO BLOCK LET TAGBODY UNLESS COND IF NOT IF >= IF
; ==>
; (< I #:G0)
; Note: Forced to do GENERIC-< (cost 10).
; Unable to do inline fixnum comparison (cost 4) because:
; The first argument is a UNSIGNED-BYTE, not a FIXNUM.
;
; --> DO BLOCK LET TAGBODY PSETQ PSETF LET* MULTIPLE-VALUE-BIND LET 1+
; ==>
; (+ I 1)
; Note: Forced to do GENERIC-+ (cost 10).
; Unable to do inline fixnum arithmetic (cost 1) because:
; The first argument is a UNSIGNED-BYTE, not a FIXNUM.
; The result is a (INTEGER 1), not a FIXNUM.
; Unable to do inline fixnum arithmetic (cost 2) because:
; The first argument is a UNSIGNED-BYTE, not a FIXNUM.
; The result is a (INTEGER 1), not a FIXNUM.
; etc.
;
But do I really have the right to do so ? The macro expansion of the
function indicates that two consecutive declarations for i are issued in that
case.
Also, I don't understand why CMU-CL gives me no note at all about the loop on
J, which behaves exactly the same.
Thanks.
--
Didier Verna, [EMAIL PROTECTED], http://www.lrde.epita.fr/~didier
EPITA / LRDE, 14-16 rue Voltaire Tel.+33 (1) 44 08 01 85
94276 Le Kremlin-Bicêtre, France Fax.+33 (1) 53 14 59 22 [EMAIL PROTECTED]
