(defun %ash/right (integer amount)
(ash integer (- amount)))
- (deftransform ash ((integer amount) (sb!vm:signed-word (integer * 0)))
+ (deftransform ash ((integer amount))
"Convert ASH of signed word to %ASH/RIGHT"
+ (unless (and (csubtypep (lvar-type integer) ; do that ourselves to avoid
+ (specifier-type 'sb!vm:signed-word)) ; optimization
+ (csubtypep (lvar-type amount) ; notes.
+ (specifier-type '(integer * 0))))
+ (give-up-ir1-transform))
(when (constant-lvar-p amount)
(give-up-ir1-transform))
(let ((use (lvar-uses amount)))
,(1- sb!vm:n-word-bits)
(- amount)))))))
- (deftransform ash ((integer amount) (word (integer * 0)))
+ (deftransform ash ((integer amount))
"Convert ASH of word to %ASH/RIGHT"
+ (unless (and (csubtypep (lvar-type integer)
+ (specifier-type 'sb!vm:word))
+ (csubtypep (lvar-type amount)
+ (specifier-type '(integer * 0))))
+ (give-up-ir1-transform))
(when (constant-lvar-p amount)
(give-up-ir1-transform))
(let ((use (lvar-uses amount)))
(def logxor -1 (lognot x))
(def logxor 0 x))
+(defun least-zero-bit (x)
+ (and (/= x -1)
+ (1- (integer-length (logxor x (1+ x))))))
+
(deftransform logand ((x y) (* (constant-arg t)) *)
"fold identity operation"
- (let ((y (lvar-value y)))
- (unless (and (plusp y)
- (= y (1- (ash 1 (integer-length y)))))
- (give-up-ir1-transform))
- (unless (csubtypep (lvar-type x)
- (specifier-type `(integer 0 ,y)))
+ (let* ((y (lvar-value y))
+ (width (or (least-zero-bit y) '*)))
+ (unless (and (neq width 0) ; (logand x 0) handled elsewhere
+ (csubtypep (lvar-type x)
+ (specifier-type `(unsigned-byte ,width))))
(give-up-ir1-transform))
'x))
(give-up-ir1-transform))
'x))
+(deftransform logior ((x y) (* (constant-arg t)) *)
+ "fold identity operation"
+ (let* ((y (lvar-value y))
+ (width (or (least-zero-bit (lognot y))
+ (give-up-ir1-transform)))) ; (logior x 0) handled elsewhere
+ (unless (csubtypep (lvar-type x)
+ (specifier-type `(integer ,(- (ash 1 width)) -1)))
+ (give-up-ir1-transform))
+ 'x))
+
;;; Pick off easy association opportunities for constant folding.
;;; More complicated stuff that also depends on commutativity
;;; (e.g. (f (f x k1) (f y k2)) => (f (f x y) (f k1 k2))) should