;;; Shifting
-(macrolet
- ((frob (name sc-type type shift-right-inst)
- `(define-vop (,name)
- (:note "inline ASH")
- (:args (number :scs (,sc-type) :to :save)
- (amount :scs (signed-reg immediate)))
- (:arg-types ,type signed-num)
- (:results (result :scs (,sc-type)))
- (:result-types ,type)
- (:translate ash)
- (:policy :fast-safe)
- (:temporary (:sc non-descriptor-reg) ndesc)
- (:generator 5
- (sc-case amount
- (signed-reg
- (cond
- ;; FIXME: These two don't look different enough.
- ((member :sparc-v9 *backend-subfeatures*)
- (let ((done (gen-label))
- (positive (gen-label)))
- (inst cmp amount)
- (inst b :ge positive)
- (inst neg ndesc amount)
- ;; ndesc = max(-amount, 31)
- (inst cmp ndesc 31)
- (inst cmove :ge ndesc 31)
- (inst b done)
- (inst ,shift-right-inst result number ndesc)
- (emit-label positive)
- ;; The result-type assures us that this shift will
- ;; not overflow.
- (inst sll result number amount)
- ;; We want a right shift of the appropriate size.
- (emit-label done)))
- (t
- (let ((positive (gen-label))
- (done (gen-label)))
- (inst cmp amount)
- (inst b :ge positive)
- (inst neg ndesc amount)
- (inst cmp ndesc 31)
- (inst b :le done)
- (inst ,shift-right-inst result number ndesc)
- (inst b done)
- (inst ,shift-right-inst result number 31)
- (emit-label positive)
- ;; The result-type assures us that this shift will
- ;; not overflow.
- (inst sll result number amount)
- (emit-label done)))))
- (immediate
- (let ((amount (tn-value amount)))
- (if (minusp amount)
- (let ((amount (min 31 (- amount))))
- (inst ,shift-right-inst result number amount))
- (inst sll result number amount)))))))))
- (frob fast-ash/signed=>signed signed-reg signed-num sra)
- (frob fast-ash/unsigned=>unsigned unsigned-reg unsigned-num srl))
+(define-vop (fast-ash/signed=>signed)
+ (:note "inline ASH")
+ (:args (number :scs (signed-reg) :to :save)
+ (amount :scs (signed-reg immediate) :to :save))
+ (:arg-types signed-num signed-num)
+ (:results (result :scs (signed-reg)))
+ (:result-types signed-num)
+ (:translate ash)
+ (:policy :fast-safe)
+ (:temporary (:sc non-descriptor-reg) ndesc)
+ (:generator 5
+ (sc-case amount
+ (signed-reg
+ (let ((done (gen-label)))
+ (inst cmp amount)
+ (inst b :ge done)
+ ;; The result-type assures us that this shift will not
+ ;; overflow.
+ (inst sll result number amount)
+ (inst neg ndesc amount)
+ (inst cmp ndesc 31)
+ (if (member :sparc-v9 *backend-subfeatures*)
+ (progn
+ (inst cmove :ge ndesc 31)
+ (inst sra result number ndesc))
+ (progn
+ (inst b :le done)
+ (inst sra result number ndesc)
+ (inst sra result number 31)))
+ (emit-label done)))
+ (immediate
+ (bug "IMMEDIATE case in ASH VOP; should have been transformed")))))
+
+(define-vop (fast-ash/unsigned=>unsigned)
+ (:note "inline ASH")
+ (:args (number :scs (unsigned-reg) :to :save)
+ (amount :scs (signed-reg immediate) :to :save))
+ (:arg-types unsigned-num signed-num)
+ (:results (result :scs (unsigned-reg)))
+ (:result-types unsigned-num)
+ (:translate ash)
+ (:policy :fast-safe)
+ (:temporary (:sc non-descriptor-reg) ndesc)
+ (:generator 5
+ (sc-case amount
+ (signed-reg
+ (let ((done (gen-label)))
+ (inst cmp amount)
+ (inst b :ge done)
+ ;; The result-type assures us that this shift will not
+ ;; overflow.
+ (inst sll result number amount)
+ (inst neg ndesc amount)
+ (inst cmp ndesc 32)
+ (if (member :sparc-v9 *backend-subfeatures*)
+ (progn
+ (inst srl result number ndesc)
+ (inst cmove :ge result zero-tn))
+ (progn
+ (inst b :lt done)
+ (inst srl result number ndesc)
+ (move result zero-tn)))
+ (emit-label done)))
+ (immediate
+ (bug "IMMEDIATE case in ASH VOP; should have been transformed")))))
;; Some special cases where we know we want a left shift. Just do the
;; shift, instead of checking for the sign of the shift.
(:policy :fast-safe)
(:generator ,cost
;; The result-type assures us that this shift will not
- ;; overflow. And for fixnum's, the zero bits that get
+ ;; overflow. And for fixnums, the zero bits that get
;; shifted in are just fine for the fixnum tag.
(sc-case amount
((signed-reg unsigned-reg)
(in-package "SB!C")
-;;; If both arguments and the result are (UNSIGNED-BYTE 32), try to
-;;; come up with a ``better'' multiplication using multiplier
-;;; recoding. There are two different ways the multiplier can be
-;;; recoded. The more obvious is to shift X by the correct amount for
-;;; each bit set in Y and to sum the results. But if there is a string
-;;; of bits that are all set, you can add X shifted by one more then
-;;; the bit position of the first set bit and subtract X shifted by
-;;; the bit position of the last set bit. We can't use this second
-;;; method when the high order bit is bit 31 because shifting by 32
-;;; doesn't work too well.
(deftransform * ((x y)
((unsigned-byte 32) (constant-arg (unsigned-byte 32)))
(unsigned-byte 32))
"recode as shifts and adds"
- (let ((y (continuation-value y))
- (adds 0)
- (shifts 0)
- (result nil)
- (first-one nil))
- (labels ((tub32 (x) `(truly-the (unsigned-byte 32) ,x))
- (add (next-factor)
- (setf result
- (tub32
- (if result
- (progn (incf adds) `(+ ,result ,(tub32 next-factor)))
- next-factor)))))
- (declare (inline add))
- (dotimes (bitpos 32)
- (if first-one
- (when (not (logbitp bitpos y))
- (add (if (= (1+ first-one) bitpos)
- ;; There is only a single bit in the string.
- (progn (incf shifts) `(ash x ,first-one))
- ;; There are at least two.
- (progn
- (incf adds)
- (incf shifts 2)
- `(- ,(tub32 `(ash x ,bitpos))
- ,(tub32 `(ash x ,first-one))))))
- (setf first-one nil))
- (when (logbitp bitpos y)
- (setf first-one bitpos))))
- (when first-one
- (cond ((= first-one 31))
- ((= first-one 30) (incf shifts) (add '(ash x 30)))
- (t
- (incf shifts 2)
- (incf adds)
- (add `(- ,(tub32 '(ash x 31)) ,(tub32 `(ash x ,first-one))))))
- (incf shifts)
- (add '(ash x 31))))
-
- (cond
- ;; we assume, perhaps foolishly, that good SPARCs don't have an
- ;; issue with multiplications. (Remember that there's a
- ;; different transform for converting x*2^k to a shift).
- ((member :sparc-64 *backend-subfeatures*) (give-up-ir1-transform))
- ((or (member :sparc-v9 *backend-subfeatures*)
- (member :sparc-v8 *backend-subfeatures*))
- ;; breakeven point as measured by Raymond Toy
- (when (> (+ adds shifts) 9)
- (give-up-ir1-transform))))
-
- (or result 0)))
+ (let ((y (lvar-value y)))
+ (multiple-value-bind (result adds shifts)
+ (ub32-strength-reduce-constant-multiply 'x y)
+ (cond
+ ;; we assume, perhaps foolishly, that good SPARCs don't have an
+ ;; issue with multiplications. (Remember that there's a
+ ;; different transform for converting x*2^k to a shift).
+ ((member :sparc-64 *backend-subfeatures*) (give-up-ir1-transform))
+ ((or (member :sparc-v9 *backend-subfeatures*)
+ (member :sparc-v8 *backend-subfeatures*))
+ ;; breakeven point as measured by Raymond Toy
+ (when (> (+ adds shifts) 9)
+ (give-up-ir1-transform))))
+ (or result 0))))
;; If we can prove that we have a right shift, just do the right shift
;; instead of calling the inline ASH which has to check for the
;; direction of the shift at run-time.
(deftransform ash ((num shift) (integer integer))
- (let ((num-type (continuation-type num))
- (shift-type (continuation-type shift)))
+ (let ((num-type (lvar-type num))
+ (shift-type (lvar-type shift)))
;; Can only handle right shifts
(unless (csubtypep shift-type (specifier-type '(integer * 0)))
(give-up-ir1-transform))
projects / sbcl.git / blobdiff