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;;; -*- Package: C; Log: C.Log -*-
;;;
;;; **********************************************************************
;;; This code was written as part of the Spice Lisp project at
;;; Carnegie-Mellon University, and has been placed in the public domain.
;;; If you want to use this code or any part of Spice Lisp, please contact
;;; Scott Fahlman (FAHLMAN@CMUC).
;;; **********************************************************************
;;;
;;; $Header: /Volumes/share2/src/cmucl/cvs2git/cvsroot/src/compiler/srctran.lisp,v 1.25 1991/01/22 12:11:15 ram Exp $
;;; This file contains macro-like source transformations which convert
;;; uses of certain functions into the canonical form desired within the
;;; compiler. ### and other IR1 transforms and stuff. Some code adapted from
;;; CLC, written by Wholey and Fahlman.
;;;
;;; Written by Rob MacLachlan
;;;
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;;; Source transform for Not, Null -- Internal
;;;
;;; Convert into an IF so that IF optimizations will eliminate redundant
;;; negations.
;;;
(def-source-transform not (x) `(if ,x nil t))
(def-source-transform null (x) `(if ,x nil t))
;;; Source transform for Endp -- Internal
;;;
;;; Endp is just NULL with a List assertion.
;;;
(def-source-transform endp (x) `(null (the list ,x)))
;;; We turn Identity into Prog1 so that it is obvious that it just returns the
;;; first value of its argument. Ditto for Values with one arg.
(def-source-transform identity (x) `(prog1 ,x))
(def-source-transform values (x) `(prog1 ,x))
;;;; List hackery:
;;;
;;; Translate CxxR into car/cdr combos.
(def-source-transform caar (x) `(car (car ,x)))
(def-source-transform cadr (x) `(car (cdr ,x)))
(def-source-transform cdar (x) `(cdr (car ,x)))
(def-source-transform cddr (x) `(cdr (cdr ,x)))
(def-source-transform caaar (x) `(car (car (car ,x))))
(def-source-transform caadr (x) `(car (car (cdr ,x))))
(def-source-transform cadar (x) `(car (cdr (car ,x))))
(def-source-transform caddr (x) `(car (cdr (cdr ,x))))
(def-source-transform cdaar (x) `(cdr (car (car ,x))))
(def-source-transform cdadr (x) `(cdr (car (cdr ,x))))
(def-source-transform cddar (x) `(cdr (cdr (car ,x))))
(def-source-transform cdddr (x) `(cdr (cdr (cdr ,x))))
(def-source-transform caaaar (x) `(car (car (car (car ,x)))))
(def-source-transform caaadr (x) `(car (car (car (cdr ,x)))))
(def-source-transform caadar (x) `(car (car (cdr (car ,x)))))
(def-source-transform caaddr (x) `(car (car (cdr (cdr ,x)))))
(def-source-transform cadaar (x) `(car (cdr (car (car ,x)))))
(def-source-transform cadadr (x) `(car (cdr (car (cdr ,x)))))
(def-source-transform caddar (x) `(car (cdr (cdr (car ,x)))))
(def-source-transform cadddr (x) `(car (cdr (cdr (cdr ,x)))))
(def-source-transform cdaaar (x) `(cdr (car (car (car ,x)))))
(def-source-transform cdaadr (x) `(cdr (car (car (cdr ,x)))))
(def-source-transform cdadar (x) `(cdr (car (cdr (car ,x)))))
(def-source-transform cdaddr (x) `(cdr (car (cdr (cdr ,x)))))
(def-source-transform cddaar (x) `(cdr (cdr (car (car ,x)))))
(def-source-transform cddadr (x) `(cdr (cdr (car (cdr ,x)))))
(def-source-transform cdddar (x) `(cdr (cdr (cdr (car ,x)))))
(def-source-transform cddddr (x) `(cdr (cdr (cdr (cdr ,x)))))
;;;
;;; Turn First..Fourth and Rest into the obvious synonym, assuming whatever is
;;; right for them is right for us. Fifth..Tenth turn into Nth, which can be
;;; expanded into a car/cdr later on if policy favors it.
(def-source-transform first (x) `(car ,x))
(def-source-transform rest (x) `(cdr ,x))
(def-source-transform second (x) `(cadr ,x))
(def-source-transform third (x) `(caddr ,x))
(def-source-transform fourth (x) `(cadddr ,x))
(def-source-transform fifth (x) `(nth 4 ,x))
(def-source-transform sixth (x) `(nth 5 ,x))
(def-source-transform seventh (x) `(nth 6 ,x))
(def-source-transform eighth (x) `(nth 7 ,x))
(def-source-transform ninth (x) `(nth 8 ,x))
(def-source-transform tenth (x) `(nth 9 ,x))
;;;
;;; Translate RPLACx to LET and SETF.
(def-source-transform rplaca (x y)
(once-only ((n-x x))
`(progn
(setf (car ,n-x) ,y)
,n-x)))
;;;
(def-source-transform rplacd (x y)
(once-only ((n-x x))
`(progn
(setf (cdr ,n-x) ,y)
,n-x)))
(def-source-transform nth (n l) `(car (nthcdr ,n ,l)))
(defvar *default-nthcdr-open-code-limit* 6)
(defvar *extreme-nthcdr-open-code-limit* 20)
(deftransform nthcdr ((n l) (unsigned-byte t) * :node node)
(unless (constant-continuation-p n) (give-up))
(let ((n (continuation-value n)))
(when (> n
(if (policy node (= speed 3) (= space 0))
*extreme-nthcdr-open-code-limit*
*default-nthcdr-open-code-limit*))
(give-up))
(labels ((frob (n)
(if (zerop n)
'l
`(cdr ,(frob (1- n))))))
(frob n))))
;;;; ARITHMETIC and NUMEROLOGY.
(def-source-transform plusp (x) `(> ,x 0))
(def-source-transform minusp (x) `(< ,x 0))
(def-source-transform zerop (x) `(= ,x 0))
(def-source-transform 1+ (x) `(+ ,x 1))
(def-source-transform 1- (x) `(- ,x 1))
(def-source-transform oddp (x) `(not (zerop (logand ,x 1))))
(def-source-transform evenp (x) `(zerop (logand ,x 1)))
;;; Note that all the integer division functions are available for inline
;;; expansion.
(macrolet ((frob (fun)
`(def-source-transform ,fun (x &optional (y nil y-p))
(declare (ignore y))
(if y-p
(values nil t)
`(,',fun ,x 1)))))
(frob truncate)
(frob round))
(def-source-transform lognand (x y) `(lognot (logand ,x ,y)))
(def-source-transform lognor (x y) `(lognot (logior ,x ,y)))
(def-source-transform logandc1 (x y) `(logand (lognot ,x) ,y))
(def-source-transform logandc2 (x y) `(logand ,x (lognot ,y)))
(def-source-transform logorc1 (x y) `(logior (lognot ,x) ,y))
(def-source-transform logorc2 (x y) `(logior ,x (lognot ,y)))
(def-source-transform logtest (x y) `(not (zerop (logand ,x ,y))))
(def-source-transform logbitp (index integer)
`(not (zerop (logand (ash 1 ,index) ,integer))))
(def-source-transform byte (size position) `(cons ,size ,position))
(def-source-transform byte-size (spec) `(car ,spec))
(def-source-transform byte-position (spec) `(cdr ,spec))
(def-source-transform ldb-test (bytespec integer)
`(not (zerop (mask-field ,bytespec ,integer))))
;;; With the ratio and complex accessors, we pick off the "identity" case, and
;;; use a primitive to handle the cell access case.
;;;
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(def-source-transform numerator (num)
(once-only ((n-num `(the rational ,num)))
`(if (ratiop ,n-num)
(%primitive numerator ,n-num)
,n-num)))
;;;
(def-source-transform denominator (num)
(once-only ((n-num `(the rational ,num)))
`(if (ratiop ,n-num)
(%primitive denominator ,n-num)
1)))
;;;
(def-source-transform realpart (num)
(once-only ((n-num num))
`(if (complexp ,n-num)
(%primitive realpart ,n-num)
,n-num)))
;;;
(def-source-transform imagpart (num)
(once-only ((n-num num))
`(cond ((complexp ,n-num)
(%primitive imagpart ,n-num))
((floatp ,n-num)
(float 0 ,n-num))
(t
0))))
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;;;; Numeric Derive-Type methods:
;;; Derive-Integer-Type -- Internal
;;;
;;; Utility for defining derive-type methods of integer operations. If the
;;; types of both X and Y are integer types, then we compute a new integer type
;;; with bounds determined Fun when applied to X and Y. Otherwise, we use
;;; Numeric-Contagion.
;;;
(defun derive-integer-type (x y fun)
(declare (type continuation x y) (type function fun))
(let ((x (continuation-type x))
(y (continuation-type y)))
(if (and (numeric-type-p x) (numeric-type-p y)
(eq (numeric-type-class x) 'integer)
(eq (numeric-type-class y) 'integer)
(eq (numeric-type-complexp x) :real)
(eq (numeric-type-complexp y) :real))
(multiple-value-bind (low high)
(funcall fun x y)
(make-numeric-type :class 'integer :complexp :real
:low low :high high))
(numeric-contagion x y))))
(defoptimizer (+ derive-type) ((x y))
(derive-integer-type
x y
#'(lambda (x y)
(flet ((frob (x y)
(if (and x y)
(+ x y)
nil)))
(values (frob (numeric-type-low x) (numeric-type-low y))
(frob (numeric-type-high x) (numeric-type-high y)))))))
(defoptimizer (- derive-type) ((x y))
(derive-integer-type
x y
#'(lambda (x y)
(flet ((frob (x y)
(if (and x y)
(- x y)
nil)))
(values (frob (numeric-type-low x) (numeric-type-high y))
(frob (numeric-type-high x) (numeric-type-low y)))))))
(defoptimizer (* derive-type) ((x y))
(derive-integer-type
x y
#'(lambda (x y)
(let ((x-low (numeric-type-low x))
(x-high (numeric-type-high x))
(y-low (numeric-type-low y))
(y-high (numeric-type-high y)))
(cond ((not (and x-low y-low))
(values nil nil))
((or (minusp x-low) (minusp y-low))
(if (and x-high y-high)
(let ((max (* (max (abs x-low) (abs x-high))
(max (abs y-low) (abs y-high)))))
(values (- max) max))
(values nil nil)))
(t
(values (* x-low y-low)
(if (and x-high y-high)
(* x-high y-high)
nil))))))))
(defoptimizer (/ derive-type) ((x y))
(numeric-contagion (continuation-type x) (continuation-type y)))
(or (let ((n-type (continuation-type n)))
(when (numeric-type-p n-type)
(let ((n-low (numeric-type-low n-type))
(n-high (numeric-type-high n-type)))
(if (constant-continuation-p shift)
(let ((shift (continuation-value shift)))
(make-numeric-type :class 'integer :complexp :real
:low (when n-low
#+new-compiler
(ash n-low shift)
;; ### fuckin' bignum bug.
#-new-compiler
(* n-low (ash 1 shift)))
:high (when n-high (ash n-high shift))))
(let ((s-type (continuation-type shift)))
(when (numeric-type-p s-type)
(let ((s-low (numeric-type-low s-type))
(s-high (numeric-type-high s-type)))
(if (and s-low s-high (<= s-low 32) (<= s-high 32))
(make-numeric-type :class 'integer :complexp :real
:low (when n-low
(min (ash n-low s-high)
(ash n-low s-low)))
:high (when n-high
(max (ash n-high s-high)
(ash n-high s-low))))
(make-numeric-type :class 'integer
:complexp :real)))))))))
*universal-type*))
(macrolet ((frob (fun)
`#'(lambda (type type2)
(declare (ignore type2))
(let ((lo (numeric-type-low type))
(hi (numeric-type-high type)))
(values (if hi (,fun hi) nil) (if lo (,fun lo) nil))))))
(defoptimizer (%negate derive-type) ((num))
(derive-integer-type num num (frob -)))
(defoptimizer (lognot derive-type) ((int))
(derive-integer-type int int (frob lognot))))
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(defoptimizer (abs derive-type) ((num))
(let ((type (continuation-type num)))
(if (and (numeric-type-p type)
(eq (numeric-type-class type) 'integer)
(eq (numeric-type-complexp type) :real))
(let ((lo (numeric-type-low type))
(hi (numeric-type-high type)))
(make-numeric-type :class 'integer :complexp :real
:low (cond ((and hi (minusp hi))
(abs hi))
(lo
(max 0 lo))
(t
0))
:high (if (and hi lo)
(max (abs hi) (abs lo))
nil)))
(numeric-contagion type type))))
(defoptimizer (truncate derive-type) ((number divisor))
(let ((number-type (continuation-type number))
(divisor-type (continuation-type divisor))
(integer-type (specifier-type 'integer)))
(if (and (numeric-type-p number-type)
(csubtypep number-type integer-type)
(numeric-type-p divisor-type)
(csubtypep divisor-type integer-type))
(let ((number-low (numeric-type-low number-type))
(number-high (numeric-type-high number-type))
(divisor-low (numeric-type-low divisor-type))
(divisor-high (numeric-type-high divisor-type)))
(values-specifier-type
`(values ,(integer-truncate-derive-type number-low number-high
divisor-low divisor-high)
,(integer-rem-derive-type number-low number-high
divisor-low divisor-high))))
*universal-type*)))
;;; NUMERIC-RANGE-INFO -- internal.
;;;
;;; Derive useful information about the range. Returns three values:
;;; - '+ if its positive, '- negative, or nil if it overlaps 0.
;;; - The abs of the minimal value (i.e. closest to 0) in the range.
;;; - The abs of the maximal value if there is one, or nil if it is unbounded.
;;;
(defun numeric-range-info (low high)
(cond ((and low (not (minusp low)))
(values '+ low high))
((and high (not (plusp high)))
(values '- (- high) (if low (- low) nil)))
(t
(values nil 0 (and low high (max (- low) high))))))
;;; INTEGER-TRUNCATE-DERIVE-TYPE -- internal
;;;
(defun integer-truncate-derive-type
(number-low number-high divisor-low divisor-high)
;; The result cannot be larger in magnitude than the number, but the sign
;; might change. If we can determine the sign of either the number or
;; the divisor, we can eliminate some of the cases.
(multiple-value-bind
(number-sign number-min number-max)
(numeric-range-info number-low number-high)
(multiple-value-bind
(divisor-sign divisor-min divisor-max)
(numeric-range-info divisor-low divisor-high)
(when (and divisor-max (zerop divisor-max))
;; We've got a problem: guarenteed division by zero.
(return-from integer-truncate-derive-type t))
(when (zerop divisor-min)
;; We'll assume that they arn't going to divide by zero.
(incf divisor-min))
(cond ((and number-sign divisor-sign)
;; We know the sign of both.
(if (eq number-sign divisor-sign)
;; Same sign, so the result will be positive.
`(integer ,(if divisor-max
(truncate number-min divisor-max)
0)
,(if number-max
(truncate number-max divisor-min)
'*))
;; Different signs, the result will be negative.
`(integer ,(if number-max
(- (truncate number-max divisor-min))
'*)
,(if divisor-max
(- (truncate number-min divisor-max))
0))))
((eq divisor-sign '+)
;; The divisor is positive. Therefore, the number will just
;; become closer to zero.
`(integer ,(if number-low
(truncate number-low divisor-min)
'*)
,(if number-high
(truncate number-high divisor-min)
'*)))
((eq divisor-sign '-)
;; The divisor is negative. Therefore, the absolute value of
;; the number will become closer to zero, but the sign will also
;; change.
`(integer ,(if number-high
(- (truncate number-high divisor-min))
'*)
,(if number-low
(- (truncate number-low divisor-min))
'*)))
;; The divisor could be either positive or negative.
(number-max
;; The number we are dividing has a bound. Divide that by the
;; smallest posible divisor.
(let ((bound (truncate number-max divisor-min)))
`(integer ,(- bound) ,bound)))
(t
;; The number we are dividing is unbounded, so we can't tell
;; anything about the result.
'integer)))))
(defun integer-rem-derive-type
(number-low number-high divisor-low divisor-high)
(if (and divisor-low divisor-high)
;; We know the range of the divisor, and the remainder must be smaller
;; than the divisor. We can tell the sign of the remainer if we know
;; the sign of the number.
(let ((divisor-max (1- (max (abs divisor-low) (abs divisor-high)))))
`(integer ,(if (or (null number-low)
(minusp number-low))
(- divisor-max)
0)
,(if (or (null number-high)
(plusp number-high))
divisor-max
0)))
;; The divisor is potentially either very positive or very negative.
;; Therefore, the remainer is unbounded, but we might be able to tell
;; something about the sign from the number.
`(integer ,(if (and number-low (not (minusp number-low)))
;; The number we are dividing is positive. Therefore,
;; the remainder must be positive.
0
'*)
,(if (and number-high (not (plusp number-high)))
;; The number we are dividing is negative. Therefore,
;; the remainder must be negative.
0
'*))))
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;;;; Logical derive-type methods:
;;; Integer-Type-Length -- Internal
;;;
;;; Return the maximum number of bits an integer of the supplied type can take
;;; up, or NIL if it is unbounded. The second (third) value is T if the
;;; integer can be positive (negative) and NIL if not. Zero counts as
;;; positive.
;;;
(defun integer-type-length (type)
(if (numeric-type-p type)
(let ((min (numeric-type-low type))
(max (numeric-type-high type)))
(values (and min max (max (integer-length min) (integer-length max)))
(or (null max) (not (minusp max)))
(or (null min) (minusp min))))
(values nil t t)))
(defoptimizer (logand derive-type) ((x y))
(multiple-value-bind
(x-len x-pos x-neg)
(integer-type-length (continuation-type x))
(declare (ignore x-pos))
(multiple-value-bind
(y-len y-pos y-neg)
(integer-type-length (continuation-type y))
(declare (ignore y-pos))
(if (not x-neg)
;; X must be positive.
(if (not y-neg)
;; The must both be positive.
(cond ((or (null x-len) (null y-len))
(specifier-type 'unsigned-byte))
((or (zerop x-len) (zerop y-len))
(specifier-type '(integer 0 0)))
(t
(specifier-type `(unsigned-byte ,(min x-len y-len)))))
;; X is positive, but Y might be negative.
(cond ((null x-len)
(specifier-type 'unsigned-byte))
((zerop x-len)
(specifier-type '(integer 0 0)))
(t
(specifier-type `(unsigned-byte ,x-len)))))
;; X might be negative.
(if (not y-neg)
;; Y must be positive.
(cond ((null y-len)
(specifier-type 'unsigned-byte))
((zerop y-len)
(specifier-type '(integer 0 0)))
(t
(specifier-type
`(unsigned-byte ,y-len))))
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;; Either might be negative.
(if (and x-len y-len)
;; The result is bounded.
(specifier-type `(signed-byte ,(1+ (max x-len y-len))))
;; We can't tell squat about the result.
(specifier-type 'integer)))))))
(defoptimizer (logior derive-type) ((x y))
(multiple-value-bind
(x-len x-pos x-neg)
(integer-type-length (continuation-type x))
(multiple-value-bind
(y-len y-pos y-neg)
(integer-type-length (continuation-type y))
(cond
((and (not x-neg) (not y-neg))
;; Both are positive.
(specifier-type `(unsigned-byte ,(if (and x-len y-len)
(max x-len y-len)
'*))))
((not x-pos)
;; X must be negative.
(if (not y-pos)
;; Both are negative. The result is going to be negative and be
;; the same length or shorter than the smaller.
(if (and x-len y-len)
;; It's bounded.
(specifier-type `(integer ,(ash -1 (min x-len y-len)) -1))
;; It's unbounded.
(specifier-type '(integer * -1)))
;; X is negative, but we don't know about Y. The result will be
;; negative, but no more negative than X.
(specifier-type
`(integer ,(or (numeric-type-low (continuation-type x)) '*)
-1))))
(t
;; X might be either positive or negative.
(if (not y-pos)
;; But Y is negative. The result will be negative.
(specifier-type
`(integer ,(or (numeric-type-low (continuation-type y)) '*)
-1))
;; We don't know squat about either. It won't get any bigger.
(if (and x-len y-len)
;; Bounded.
(specifier-type `(signed-byte ,(1+ (max x-len y-len))))
;; Unbounded.
(specifier-type 'integer))))))))
(defoptimizer (logxor derive-type) ((x y))
(multiple-value-bind
(x-len x-pos x-neg)
(integer-type-length (continuation-type x))
(multiple-value-bind
(y-len y-pos y-neg)
(integer-type-length (continuation-type y))
(cond
((or (and (not x-neg) (not y-neg))
(and (not x-pos) (not y-pos)))
;; Either both are negative or both are positive. The result will be
;; positive, and as long as the longer.
(specifier-type `(unsigned-byte ,(if (and x-len y-len)
(max x-len y-len)
'*))))
((or (and (not x-pos) (not y-neg))
(and (not y-neg) (not y-pos)))
;; Either X is negative and Y is positive of vice-verca. The result
;; will be negative.
(specifier-type `(integer ,(if (and x-len y-len)
(ash -1 (max x-len y-len))
'*)
-1)))
;; We can't tell what the sign of the result is going to be. All we
;; know is that we don't create new bits.
((and x-len y-len)
(specifier-type `(signed-byte ,(1+ (max x-len y-len)))))
(t
(specifier-type 'integer))))))
;;;; Miscellaneous derive-type methods:
(specifier-type 'base-character))
(defoptimizer (values derive-type) ((&rest values))
(values-specifier-type
`(values ,@(mapcar #'(lambda (x)
(type-specifier (continuation-type x)))
values))))
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;;;; Byte operations:
;;;
;;; We try to turn byte operations into simple logical operations. First,
;;; we convert byte specifiers into separate size and position arguments passed
;;; to internal %FOO functions. We then attempt to transform the %FOO
;;; functions into boolean operations when the size and position are constant
;;; and the operands are fixnums.
;;; With-Byte-Specifier -- Internal
;;;
;;; Evaluate body with Size-Var and Pos-Var bound to expressions that
;;; evaluate to the Size and Position of the byte-specifier form Spec. We may
;;; wrap a let around the result of the body to bind some variables.
;;;
;;; If the spec is a Byte form, then bind the vars to the subforms.
;;; otherwise, evaluate Spec and use the Byte-Size and Byte-Position. The goal
;;; of this transformation is to avoid consing up byte specifiers and then
;;; immediately throwing them away.
;;;
(defmacro with-byte-specifier ((size-var pos-var spec) &body body)
(once-only ((spec `(macroexpand ,spec))
(temp '(gensym)))
`(if (and (consp ,spec)
(eq (car ,spec) 'byte)
(= (length ,spec) 3))
(let ((,size-var (second ,spec))
(,pos-var (third ,spec)))
,@body)
(let ((,size-var `(byte-size ,,temp))
(,pos-var `(byte-position ,,temp)))
`(let ((,,temp ,,spec))
,,@body)))))
(def-source-transform ldb (spec int)
(with-byte-specifier (size pos spec)
`(%ldb ,size ,pos ,int)))
(def-source-transform dpb (newbyte spec int)
(with-byte-specifier (size pos spec)
`(%dpb ,newbyte ,size ,pos ,int)))
(def-source-transform mask-field (spec int)
(with-byte-specifier (size pos spec)
`(%mask-field ,size ,pos ,int)))
(def-source-transform deposit-field (newbyte spec int)
(with-byte-specifier (size pos spec)
`(%deposit-field ,newbyte ,size ,pos ,int)))
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(defoptimizer (%ldb derive-type) ((size posn num))
(let ((size (continuation-type size)))
(if (and (numeric-type-p size)
(csubtypep size (specifier-type 'integer)))
(let ((size-high (numeric-type-high size)))
(if (and size-high (<= size-high vm:word-bits))
(specifier-type `(unsigned-byte ,size-high))
(specifier-type 'unsigned-byte)))
*universal-type*)))
(defoptimizer (%mask-field derive-type) ((size posn num))
(let ((size (continuation-type size))
(posn (continuation-type posn)))
(if (and (numeric-type-p size)
(csubtypep size (specifier-type 'integer))
(numeric-type-p posn)
(csubtypep posn (specifier-type 'integer)))
(let ((size-high (numeric-type-high size))
(posn-high (numeric-type-high posn)))
(if (and size-high posn-high
(<= (+ size-high posn-high) vm:word-bits))
(specifier-type `(unsigned-byte ,(+ size-high posn-high)))
(specifier-type 'unsigned-byte)))
*universal-type*)))
(defoptimizer (%dpb derive-type) ((newbyte size posn int))
(let ((size (continuation-type size))
(posn (continuation-type posn))
(int (continuation-type int)))
(if (and (numeric-type-p size)
(csubtypep size (specifier-type 'integer))
(numeric-type-p posn)
(csubtypep posn (specifier-type 'integer))
(numeric-type-p int)
(csubtypep int (specifier-type 'integer)))
(let ((size-high (numeric-type-high size))
(posn-high (numeric-type-high posn))
(high (numeric-type-high int))
(low (numeric-type-low int)))
(if (and size-high posn-high high low
(<= (+ size-high posn-high) vm:word-bits))
(specifier-type
(list (if (minusp low) 'signed-byte 'unsigned-byte)
(max (integer-length high)
(integer-length low)
(+ size-high posn-high))))
*universal-type*))
*universal-type*)))
(defoptimizer (%deposit-field derive-type) ((newbyte size posn int))
(let ((size (continuation-type size))
(posn (continuation-type posn))
(int (continuation-type int)))
(if (and (numeric-type-p size)
(csubtypep size (specifier-type 'integer))
(numeric-type-p posn)
(csubtypep posn (specifier-type 'integer))
(numeric-type-p int)
(csubtypep int (specifier-type 'integer)))
(let ((size-high (numeric-type-high size))
(posn-high (numeric-type-high posn))
(high (numeric-type-high int))
(low (numeric-type-low int)))
(if (and size-high posn-high high low
(<= (+ size-high posn-high) vm:word-bits))
(specifier-type
(list (if (minusp low) 'signed-byte 'unsigned-byte)
(max (integer-length high)
(integer-length low)
(+ size-high posn-high))))
*universal-type*))
*universal-type*)))
(deftransform %ldb ((size posn int)
(fixnum fixnum integer)
(unsigned-byte #.vm:word-bits))
`(logand (ash int (- posn))
(ash ,(1- (ash 1 vm:word-bits))
(- size ,vm:word-bits))))
(deftransform %mask-field ((size posn int)
(fixnum fixnum integer)
(unsigned-byte #.vm:word-bits))
`(logand int
(ash (ash ,(1- (ash 1 vm:word-bits))
(- size ,vm:word-bits))
posn)))
;;; Note: for %dpb and %deposit-field, we can't use (or (signed-byte n)
;;; (unsigned-byte n)) as the result type, as that would allow result types
;;; that cover the range -2^(n-1) .. 1-2^n, instead of allowing result types
;;; of (unsigned-byte n) and result types of (signed-byte n).
(deftransform %dpb ((new size posn int)
*
(unsigned-byte #.vm:word-bits))
`(let ((mask (ldb (byte size 0) -1)))
(logior (ash (logand new mask) posn)
(logand int (lognot (ash mask posn))))))
(deftransform %dpb ((new size posn int)
*
(signed-byte #.vm:word-bits))
`(let ((mask (ldb (byte size 0) -1)))
(logior (ash (logand new mask) posn)
(logand int (lognot (ash mask posn))))))
(deftransform %deposit-field ((new size posn int)
*
(unsigned-byte #.vm:word-bits))
`(let ((mask (ash (ldb (byte size 0) -1) posn)))
(logior (logand new mask)
(logand int (lognot mask)))))
(deftransform %deposit-field ((new size posn int)
*
(signed-byte #.vm:word-bits))
`(let ((mask (ash (ldb (byte size 0) -1) posn)))
(logior (logand new mask)
(logand int (lognot mask)))))
;;;; Funny function stubs:
;;;
;;; These functions are the result of compiler transformations. We never
;;; actually compile a call to these functions, but we need to have a
;;; definition to allow constant folding.
;;;
(defun %negate (x) (%primitive negate x))
(defun %ldb (s p i) (%primitive ldb s p i))
(defun %dpb (n s p i) (%primitive dpb n s p i))
(defun %mask-field (s p i) (%primitive mask-field s p i))
(defun %deposit-field (n s p i) (%primitive deposit-field n s p i))
;;; COMMUTATIVE-ARG-SWAP -- Internal
;;;
;;; If a constant appears as the first arg, swap the args.
;;;
(deftransform commutative-arg-swap ((x y) * * :defun-only t :node node)
(if (and (constant-continuation-p x)
(not (constant-continuation-p y)))
`(,(continuation-function-name (basic-combination-fun node)) y x)
(give-up)))
(dolist (x '(= char= + * logior logand logxor))
(%deftransform x '(function * *) #'commutative-arg-swap))
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;;; Handle the case of a constant boole-code.
;;;
(deftransform boole ((op x y))
(unless (constant-continuation-p op)
(give-up "BOOLE code is not a constant."))
(let ((control (continuation-value op)))
(case control
(#.boole-clr 0)
(#.boole-set -1)
(#.boole-1 'x)
(#.boole-2 'y)
(#.boole-c1 '(lognot x))
(#.boole-c2 '(lognot y))
(#.boole-and '(logand x y))
(#.boole-ior '(logior x y))
(#.boole-xor '(logxor x y))
(#.boole-eqv '(logeqv x y))
(#.boole-nand '(lognand x y))
(#.boole-nor '(lognor x y))
(#.boole-andc1 '(logandc1 x y))
(#.boole-andc2 '(logandc2 x y))
(#.boole-orc1 '(logorc1 x y))
(#.boole-orc2 '(logorc2 x y))
(t
(abort-transform "~S illegal control arg to BOOLE." control)))))
;;; If arg is a constant power of two, turn * into a shift.
;;;
(deftransform * ((x y) (integer integer))
(unless (constant-continuation-p y) (give-up))
(let* ((y (continuation-value y))
(y-abs (abs y))
(len (1- (integer-length y-abs))))
(unless (= y-abs (ash 1 len)) (give-up))
(if (minusp y)
`(- (ash x ,len))
`(ash x ,len))))
;;; If arg is a constant power of two, turn floor into a shift and mask.
;;; If ceiling, add in (1- (abs y)) and then do floor.
;;;
(flet ((frob (y ceil-p)
(unless (constant-continuation-p y) (give-up))
(let* ((y (continuation-value y))
(y-abs (abs y))
(len (1- (integer-length y-abs))))
(unless (= y-abs (ash 1 len)) (give-up))
(let ((shift (- len))
(mask (1- y-abs)))
`(let ,(when ceil-p `((x (+ x ,(1- y-abs)))))
,(if (minusp y)
`(values (ash (- x) ,shift)
(- (logand (- x) ,mask)))
`(values (ash x ,shift)
(logand x ,mask))))))))
(deftransform floor ((x y) (integer integer))
(frob y nil))
(deftransform ceiling ((x y) (integer integer))
(frob y t)))
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;;; Do the same for mod.
;;;
(deftransform mod ((x y) (integer integer))
(unless (constant-continuation-p y) (give-up))
(let* ((y (continuation-value y))
(y-abs (abs y))
(len (1- (integer-length y-abs))))
(unless (= y-abs (ash 1 len)) (give-up))
(let ((mask (1- y-abs)))
(if (minusp y)
`(- (logand (- x) ,mask))
`(logand x ,mask)))))
;;; If arg is a constant power of two, turn truncate into a shift and mask.
;;;
(deftransform truncate ((x y) (integer integer))
(unless (constant-continuation-p y) (give-up))
(let* ((y (continuation-value y))
(y-abs (abs y))
(len (1- (integer-length y-abs))))
(unless (= y-abs (ash 1 len)) (give-up))
(let* ((shift (- len))
(mask (1- y-abs)))
`(if (minusp x)
(values ,(if (minusp y)
`(ash (- x) ,shift)
`(- (ash (- x) ,shift)))
(- (logand (- x) ,mask)))
(values ,(if (minusp y)
`(- (ash (- x) ,shift))
`(ash x ,shift))
(logand x ,mask))))))
;;; And the same for rem.
;;;
(deftransform rem ((x y) (integer integer))
(unless (constant-continuation-p y) (give-up))
(let* ((y (continuation-value y))
(y-abs (abs y))
(len (1- (integer-length y-abs))))
(unless (= y-abs (ash 1 len)) (give-up))
(let ((mask (1- y-abs)))
`(if (minusp x)
(- (logand (- x) ,mask))
(logand x ,mask)))))
;;; Flush calls to random arith functions that convert to the identity
;;; function.
;;;
(deftransform ash ((x y) (* (constant-argument (member 0))))
'x)
(deftransform char-equal ((a b) (base-character base-character))
'(let* ((ac (char-code a))
(bc (char-code b))
(sum (logxor ac bc)))
(or (zerop sum)
(when (eql sum #x20)
(let ((sum (+ ac bc)))
(and (> sum 161) (< sum 213)))))))
(deftransform char-upcase ((x) (base-character))
'(let ((n-code (char-code x)))
(if (and (> n-code #o140) ; Octal 141 is #\a.
(< n-code #o173)) ; Octal 172 is #\z.
(code-char (logxor #x20 n-code))
x)))
(deftransform char-downcase ((x) (base-character))
'(let ((n-code (char-code x)))
(if (and (> n-code 64) ; 65 is #\A.
(< n-code 91)) ; 90 is #\Z.
(code-char (logxor #x20 n-code))
x)))
;;;; Equality predicate transforms:
;;; SAME-LEAF-REF-P -- Internal
;;;
;;; Return true if X and Y are continuations whose only use is a reference
;;; to the same leaf, and the value of the leaf cannot change.
;;;
(defun same-leaf-ref-p (x y)
(declare (type continuation x y))
(let ((x-use (continuation-use x))
(y-use (continuation-use y)))
(and (ref-p x-use)
(ref-p y-use)
(eq (ref-leaf x-use) (ref-leaf y-use))
(constant-reference-p x-use))))
;;; SIMPLE-EQUALITY-TRANSFORM -- Internal
;;;
;;; If X and Y are the same leaf, then the result is true. Otherwise, if
;;; there is no intersection between the types of the arguments, then the
;;; result is definitely false.
;;;
(deftransform simple-equality-transform ((x y) * * :defun-only t)
(cond ((same-leaf-ref-p x y)
't)
((not (types-intersect (continuation-type x) (continuation-type y)))
'nil)