X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcompiler%2Fsrctran.lisp;h=728e7415a3c5dfdb112a9124589871988710daa4;hb=a8419eb994f3b59b70cfa12e1004711a830a43fa;hp=f6369e6977cb25b5d81fd5f165ddaaa0ab1b2a78;hpb=ccd2a1d4ab60a9539472df45fc4f9ec7b7fdc7b7;p=sbcl.git

diff --git a/src/compiler/srctran.lisp b/src/compiler/srctran.lisp
index f6369e6..728e741 100644
--- a/src/compiler/srctran.lisp
+++ b/src/compiler/srctran.lisp
@@ -134,6 +134,11 @@
     (1 `(cons ,(first args) nil))
     (t (values nil t))))
 
+(defoptimizer (list derive-type) ((&rest args) node)
+  (if args
+      (specifier-type 'cons)
+      (specifier-type 'null)))
+
 ;;; And similarly for LIST*.
 (define-source-transform list* (arg &rest others)
   (cond ((not others) arg)
@@ -145,6 +150,63 @@
       (specifier-type 'cons)
       (lvar-type arg)))
 
+;;;
+
+(define-source-transform nconc (&rest args)
+  (case (length args)
+    (0 ())
+    (1 (car args))
+    (t (values nil t))))
+
+;;; (append nil nil nil fixnum) => fixnum
+;;; (append x x cons x x) => cons
+;;; (append x x x x list) => list
+;;; (append x x x x sequence) => sequence
+;;; (append fixnum x ...) => nil
+(defun derive-append-type (args)
+  (when (null args)
+    (return-from derive-append-type (specifier-type 'null)))
+  (let* ((cons-type (specifier-type 'cons))
+         (null-type (specifier-type 'null))
+         (list-type (specifier-type 'list))
+         (last (lvar-type (car (last args)))))
+    ;; Derive the actual return type, assuming that all but the last
+    ;; arguments are LISTs (otherwise, APPEND/NCONC doesn't return).
+    (loop with all-nil = t       ; all but the last args are NIL?
+          with some-cons = nil   ; some args are conses?
+          for (arg next) on args
+          for lvar-type = (type-approx-intersection2 (lvar-type arg)
+                                                     list-type)
+          while next
+          do (multiple-value-bind (typep definitely)
+                 (ctypep nil lvar-type)
+               (cond ((type= lvar-type *empty-type*)
+                      ;; type mismatch! insert an inline check that'll cause
+                      ;; compile-time warnings.
+                      (assert-lvar-type arg list-type
+                                        (lexenv-policy *lexenv*)))
+                     (some-cons) ; we know result's a cons -- nothing to do
+                     ((and (not typep) definitely) ; can't be NIL
+                      (setf some-cons t))          ; must be a CONS
+                     (all-nil
+                      (setf all-nil (csubtypep lvar-type null-type)))))
+          finally
+             ;; if some of the previous arguments are CONSes so is the result;
+             ;; if all the previous values are NIL, we're a fancy identity;
+             ;; otherwise, could be either
+             (return (cond (some-cons cons-type)
+                           (all-nil last)
+                           (t (type-union last cons-type)))))))
+
+(defoptimizer (append derive-type) ((&rest args))
+  (derive-append-type args))
+
+(defoptimizer (sb!impl::append2 derive-type) ((&rest args))
+  (derive-append-type args))
+
+(defoptimizer (nconc derive-type) ((&rest args))
+  (derive-append-type args))
+
 ;;; Translate RPLACx to LET and SETF.
 (define-source-transform rplaca (x y)
   (once-only ((n-x x))
@@ -236,8 +298,24 @@
 ;;; on the argument types), but we make it a regular transform so that
 ;;; the VM has a chance to see the bare LOGTEST and potentiall choose
 ;;; to implement it differently.  --njf, 06-02-2006
-(deftransform logtest ((x y) * *)
-  `(not (zerop (logand x y))))
+;;;
+;;; Other transforms may be useful even with direct LOGTEST VOPs; let
+;;; them fire (including the type-directed constant folding below), but
+;;; disable the inlining rewrite in such cases. -- PK, 2013-05-20
+(deftransform logtest ((x y) * * :node node)
+  (let ((type (two-arg-derive-type x y
+                                   #'logand-derive-type-aux
+                                   #'logand)))
+    (multiple-value-bind (typep definitely)
+        (ctypep 0 type)
+      (cond ((and (not typep) definitely)
+             t)
+            ((type= type (specifier-type '(eql 0)))
+             nil)
+            ((neq :default (combination-implementation-style node))
+             (give-up-ir1-transform))
+            (t
+             `(not (zerop (logand x y))))))))
 
 (deftransform logbitp
     ((index integer) (unsigned-byte (or (signed-byte #.sb!vm:n-word-bits)
@@ -2393,305 +2471,6 @@
 (defoptimizer (random derive-type) ((bound &optional state))
   (one-arg-derive-type bound #'random-derive-type-aux nil))
 
-;;;; DERIVE-TYPE methods for LOGAND, LOGIOR, and friends
-
-;;; 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)))
-
-;;; See _Hacker's Delight_, Henry S. Warren, Jr. pp 58-63 for an
-;;; explanation of LOG{AND,IOR,XOR}-DERIVE-UNSIGNED-{LOW,HIGH}-BOUND.
-;;; Credit also goes to Raymond Toy for writing (and debugging!) similar
-;;; versions in CMUCL, from which these functions copy liberally.
-
-(defun logand-derive-unsigned-low-bound (x y)
-  (let ((a (numeric-type-low x))
-        (b (numeric-type-high x))
-        (c (numeric-type-low y))
-        (d (numeric-type-high y)))
-    (loop for m = (ash 1 (integer-length (lognor a c))) then (ash m -1)
-          until (zerop m) do
-          (unless (zerop (logand m (lognot a) (lognot c)))
-            (let ((temp (logandc2 (logior a m) (1- m))))
-              (when (<= temp b)
-                (setf a temp)
-                (loop-finish))
-              (setf temp (logandc2 (logior c m) (1- m)))
-              (when (<= temp d)
-                (setf c temp)
-                (loop-finish))))
-          finally (return (logand a c)))))
-
-(defun logand-derive-unsigned-high-bound (x y)
-  (let ((a (numeric-type-low x))
-        (b (numeric-type-high x))
-        (c (numeric-type-low y))
-        (d (numeric-type-high y)))
-    (loop for m = (ash 1 (integer-length (logxor b d))) then (ash m -1)
-          until (zerop m) do
-          (cond
-            ((not (zerop (logand b (lognot d) m)))
-             (let ((temp (logior (logandc2 b m) (1- m))))
-               (when (>= temp a)
-                 (setf b temp)
-                 (loop-finish))))
-            ((not (zerop (logand (lognot b) d m)))
-             (let ((temp (logior (logandc2 d m) (1- m))))
-               (when (>= temp c)
-                 (setf d temp)
-                 (loop-finish)))))
-          finally (return (logand b d)))))
-
-(defun logand-derive-type-aux (x y &optional same-leaf)
-  (when same-leaf
-    (return-from logand-derive-type-aux x))
-  (multiple-value-bind (x-len x-pos x-neg) (integer-type-length x)
-    (declare (ignore x-pos))
-    (multiple-value-bind (y-len y-pos y-neg) (integer-type-length y)
-      (declare (ignore y-pos))
-      (if (not x-neg)
-          ;; X must be positive.
-          (if (not y-neg)
-              ;; They must both be positive.
-              (cond ((and (null x-len) (null y-len))
-                     (specifier-type 'unsigned-byte))
-                    ((null x-len)
-                     (specifier-type `(unsigned-byte* ,y-len)))
-                    ((null y-len)
-                     (specifier-type `(unsigned-byte* ,x-len)))
-                    (t
-                     (let ((low (logand-derive-unsigned-low-bound x y))
-                           (high (logand-derive-unsigned-high-bound x y)))
-                       (specifier-type `(integer ,low ,high)))))
-              ;; X is positive, but Y might be negative.
-              (cond ((null x-len)
-                     (specifier-type 'unsigned-byte))
-                    (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))
-                    (t (specifier-type `(unsigned-byte* ,y-len))))
-              ;; 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)))))))
-
-(defun logior-derive-unsigned-low-bound (x y)
-  (let ((a (numeric-type-low x))
-        (b (numeric-type-high x))
-        (c (numeric-type-low y))
-        (d (numeric-type-high y)))
-    (loop for m = (ash 1 (integer-length (logxor a c))) then (ash m -1)
-          until (zerop m) do
-          (cond
-            ((not (zerop (logandc2 (logand c m) a)))
-             (let ((temp (logand (logior a m) (1+ (lognot m)))))
-               (when (<= temp b)
-                 (setf a temp)
-                 (loop-finish))))
-            ((not (zerop (logandc2 (logand a m) c)))
-             (let ((temp (logand (logior c m) (1+ (lognot m)))))
-               (when (<= temp d)
-                 (setf c temp)
-                 (loop-finish)))))
-          finally (return (logior a c)))))
-
-(defun logior-derive-unsigned-high-bound (x y)
-  (let ((a (numeric-type-low x))
-        (b (numeric-type-high x))
-        (c (numeric-type-low y))
-        (d (numeric-type-high y)))
-    (loop for m = (ash 1 (integer-length (logand b d))) then (ash m -1)
-          until (zerop m) do
-          (unless (zerop (logand b d m))
-            (let ((temp (logior (- b m) (1- m))))
-              (when (>= temp a)
-                (setf b temp)
-                (loop-finish))
-              (setf temp (logior (- d m) (1- m)))
-              (when (>= temp c)
-                (setf d temp)
-                (loop-finish))))
-          finally (return (logior b d)))))
-
-(defun logior-derive-type-aux (x y &optional same-leaf)
-  (when same-leaf
-    (return-from logior-derive-type-aux x))
-  (multiple-value-bind (x-len x-pos x-neg) (integer-type-length x)
-    (multiple-value-bind (y-len y-pos y-neg) (integer-type-length y)
-      (cond
-       ((and (not x-neg) (not y-neg))
-        ;; Both are positive.
-        (if (and x-len y-len)
-            (let ((low (logior-derive-unsigned-low-bound x y))
-                  (high (logior-derive-unsigned-high-bound x y)))
-              (specifier-type `(integer ,low ,high)))
-            (specifier-type `(unsigned-byte* *))))
-       ((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 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 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))))))))
-
-(defun logxor-derive-unsigned-low-bound (x y)
-  (let ((a (numeric-type-low x))
-        (b (numeric-type-high x))
-        (c (numeric-type-low y))
-        (d (numeric-type-high y)))
-    (loop for m = (ash 1 (integer-length (logxor a c))) then (ash m -1)
-          until (zerop m) do
-          (cond
-            ((not (zerop (logandc2 (logand c m) a)))
-             (let ((temp (logand (logior a m)
-                                 (1+ (lognot m)))))
-               (when (<= temp b)
-                 (setf a temp))))
-            ((not (zerop (logandc2 (logand a m) c)))
-             (let ((temp (logand (logior c m)
-                                 (1+ (lognot m)))))
-               (when (<= temp d)
-                 (setf c temp)))))
-          finally (return (logxor a c)))))
-
-(defun logxor-derive-unsigned-high-bound (x y)
-  (let ((a (numeric-type-low x))
-        (b (numeric-type-high x))
-        (c (numeric-type-low y))
-        (d (numeric-type-high y)))
-    (loop for m = (ash 1 (integer-length (logand b d))) then (ash m -1)
-          until (zerop m) do
-          (unless (zerop (logand b d m))
-            (let ((temp (logior (- b m) (1- m))))
-              (cond
-                ((>= temp a) (setf b temp))
-                (t (let ((temp (logior (- d m) (1- m))))
-                     (when (>= temp c)
-                       (setf d temp)))))))
-          finally (return (logxor b d)))))
-
-(defun logxor-derive-type-aux (x y &optional same-leaf)
-  (when same-leaf
-    (return-from logxor-derive-type-aux (specifier-type '(eql 0))))
-  (multiple-value-bind (x-len x-pos x-neg) (integer-type-length x)
-    (multiple-value-bind (y-len y-pos y-neg) (integer-type-length y)
-      (cond
-        ((and (not x-neg) (not y-neg))
-         ;; Both are positive
-         (if (and x-len y-len)
-             (let ((low (logxor-derive-unsigned-low-bound x y))
-                   (high (logxor-derive-unsigned-high-bound x y)))
-               (specifier-type `(integer ,low ,high)))
-             (specifier-type '(unsigned-byte* *))))
-        ((and (not x-pos) (not y-pos))
-         ;; Both are negative.  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-pos) (not x-neg)))
-         ;; Either X is negative and Y is positive or vice-versa. 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))))))
-
-(macrolet ((deffrob (logfun)
-             (let ((fun-aux (symbolicate logfun "-DERIVE-TYPE-AUX")))
-             `(defoptimizer (,logfun derive-type) ((x y))
-                (two-arg-derive-type x y #',fun-aux #',logfun)))))
-  (deffrob logand)
-  (deffrob logior)
-  (deffrob logxor))
-
-(defoptimizer (logeqv derive-type) ((x y))
-  (two-arg-derive-type x y (lambda (x y same-leaf)
-                             (lognot-derive-type-aux
-                              (logxor-derive-type-aux x y same-leaf)))
-                       #'logeqv))
-(defoptimizer (lognand derive-type) ((x y))
-  (two-arg-derive-type x y (lambda (x y same-leaf)
-                             (lognot-derive-type-aux
-                              (logand-derive-type-aux x y same-leaf)))
-                       #'lognand))
-(defoptimizer (lognor derive-type) ((x y))
-  (two-arg-derive-type x y (lambda (x y same-leaf)
-                             (lognot-derive-type-aux
-                              (logior-derive-type-aux x y same-leaf)))
-                       #'lognor))
-(defoptimizer (logandc1 derive-type) ((x y))
-  (two-arg-derive-type x y (lambda (x y same-leaf)
-                             (if same-leaf
-                                 (specifier-type '(eql 0))
-                                 (logand-derive-type-aux
-                                  (lognot-derive-type-aux x) y nil)))
-                       #'logandc1))
-(defoptimizer (logandc2 derive-type) ((x y))
-  (two-arg-derive-type x y (lambda (x y same-leaf)
-                             (if same-leaf
-                                 (specifier-type '(eql 0))
-                                 (logand-derive-type-aux
-                                  x (lognot-derive-type-aux y) nil)))
-                       #'logandc2))
-(defoptimizer (logorc1 derive-type) ((x y))
-  (two-arg-derive-type x y (lambda (x y same-leaf)
-                             (if same-leaf
-                                 (specifier-type '(eql -1))
-                                 (logior-derive-type-aux
-                                  (lognot-derive-type-aux x) y nil)))
-                       #'logorc1))
-(defoptimizer (logorc2 derive-type) ((x y))
-  (two-arg-derive-type x y (lambda (x y same-leaf)
-                             (if same-leaf
-                                 (specifier-type '(eql -1))
-                                 (logior-derive-type-aux
-                                  x (lognot-derive-type-aux y) nil)))
-                       #'logorc2))
-
 ;;;; miscellaneous derive-type methods
 
 (defoptimizer (integer-length derive-type) ((x))
@@ -2985,7 +2764,88 @@
               (specifier-type `(signed-byte ,size-high))
               *universal-type*))
         *universal-type*)))
+
+;;; Rightward ASH
+#!+ash-right-vops
+(progn
+  (defun %ash/right (integer amount)
+    (ash integer (- amount)))
+
+  (deftransform ash ((integer amount) (sb!vm:signed-word (integer * 0)))
+    "Convert ASH of signed word to %ASH/RIGHT"
+    (when (constant-lvar-p amount)
+      (give-up-ir1-transform))
+    (let ((use (lvar-uses amount)))
+      (cond ((and (combination-p use)
+                  (eql '%negate (lvar-fun-name (combination-fun use))))
+             (splice-fun-args amount '%negate 1)
+             `(lambda (integer amount)
+                (declare (type unsigned-byte amount))
+                (%ash/right integer (if (>= amount ,sb!vm:n-word-bits)
+                                        ,(1- sb!vm:n-word-bits)
+                                        amount))))
+            (t
+             `(%ash/right integer (if (<= amount ,(- sb!vm:n-word-bits))
+                                      ,(1- sb!vm:n-word-bits)
+                                      (- amount)))))))
+
+  (deftransform ash ((integer amount) (word (integer * 0)))
+    "Convert ASH of word to %ASH/RIGHT"
+    (when (constant-lvar-p amount)
+      (give-up-ir1-transform))
+    (let ((use (lvar-uses amount)))
+      (cond ((and (combination-p use)
+                  (eql '%negate (lvar-fun-name (combination-fun use))))
+             (splice-fun-args amount '%negate 1)
+             `(lambda (integer amount)
+                (declare (type unsigned-byte amount))
+                (if (>= amount ,sb!vm:n-word-bits)
+                    0
+                    (%ash/right integer amount))))
+            (t
+             `(if (<= amount ,(- sb!vm:n-word-bits))
+                  0
+                  (%ash/right integer (- amount)))))))
+
+  (deftransform %ash/right ((integer amount) (integer (constant-arg unsigned-byte)))
+    "Convert %ASH/RIGHT by constant back to ASH"
+    `(ash integer ,(- (lvar-value amount))))
+
+  (deftransform %ash/right ((integer amount) * * :node node)
+    "strength reduce large variable right shift"
+    (let ((return-type (single-value-type (node-derived-type node))))
+      (cond ((type= return-type (specifier-type '(eql 0)))
+             0)
+            ((type= return-type (specifier-type '(eql -1)))
+             -1)
+            ((csubtypep return-type (specifier-type '(member -1 0)))
+             `(ash integer ,(- sb!vm:n-word-bits)))
+            (t
+             (give-up-ir1-transform)))))
+
+  (defun %ash/right-derive-type-aux (n-type shift same-arg)
+    (declare (ignore same-arg))
+    (or (and (or (csubtypep n-type (specifier-type 'sb!vm:signed-word))
+                 (csubtypep n-type (specifier-type 'word)))
+             (csubtypep shift (specifier-type `(mod ,sb!vm:n-word-bits)))
+             (let ((n-low (numeric-type-low n-type))
+                   (n-high (numeric-type-high n-type))
+                   (s-low (numeric-type-low shift))
+                   (s-high (numeric-type-high shift)))
+               (make-numeric-type :class 'integer :complexp :real
+                                  :low (when n-low
+                                         (if (minusp n-low)
+                                             (ash n-low (- s-low))
+                                             (ash n-low (- s-high))))
+                                  :high (when n-high
+                                          (if (minusp n-high)
+                                              (ash n-high (- s-high))
+                                              (ash n-high (- s-low)))))))
+        *universal-type*))
 
+  (defoptimizer (%ash/right derive-type) ((n shift))
+    (two-arg-derive-type n shift #'%ash/right-derive-type-aux #'%ash/right))
+  )
 
 ;;; Modular functions
 
@@ -3050,58 +2910,121 @@
                (setf (node-reoptimize node) t)
                (setf (block-reoptimize (node-block node)) t)
                (reoptimize-component (node-component node) :maybe))
+             (insert-lvar-cut (lvar)
+               "Insert a LOGAND/MASK-SIGNED-FIELD to cut the value of LVAR
+                to the required bit width. Returns T if any change was made.
+
+                When the destination of LVAR will definitely cut LVAR's value
+                to width (i.e. it's a logand or mask-signed-field with constant
+                other argument), do nothing. Otherwise, splice LOGAND/M-S-F in."
+               (binding* ((dest (lvar-dest lvar) :exit-if-null)
+                          (nil  (combination-p dest) :exit-if-null)
+                          (name (lvar-fun-name (combination-fun dest) t))
+                          (args (combination-args dest)))
+                 (case name
+                   (logand
+                    (when (= 2 (length args))
+                      (let ((other (if (eql (first args) lvar)
+                                       (second args)
+                                       (first args))))
+                        (when (and (constant-lvar-p other)
+                                   (ctypep (lvar-value other) type)
+                                   (not signedp))
+                          (return-from insert-lvar-cut)))))
+                   (mask-signed-field
+                    (when (and signedp
+                               (eql lvar (second args))
+                               (constant-lvar-p (first args))
+                               (<= (lvar-value (first args)) width))
+                      (return-from insert-lvar-cut)))))
+               (filter-lvar lvar
+                            (if signedp
+                                `(mask-signed-field ,width 'dummy)
+                                `(logand 'dummy ,(ldb (byte width 0) -1))))
+               (do-uses (node lvar)
+                 (setf (block-reoptimize (node-block node)) t)
+                 (reoptimize-component (node-component node) :maybe))
+               t)
              (cut-node (node &aux did-something)
-               (when (and (not (block-delete-p (node-block node)))
-                          (ref-p node)
-                          (constant-p (ref-leaf node)))
-                 (let* ((constant-value (constant-value (ref-leaf node)))
-                        (new-value (if signedp
-                                       (mask-signed-field width constant-value)
-                                       (ldb (byte width 0) constant-value))))
-                   (unless (= constant-value new-value)
-                     (change-ref-leaf node (make-constant new-value))
-                     (let ((lvar (node-lvar node)))
-                       (setf (lvar-%derived-type lvar)
-                             (and (lvar-has-single-use-p lvar)
-                                  (make-values-type :required (list (ctype-of new-value))))))
-                     (setf (block-reoptimize (node-block node)) t)
-                     (reoptimize-component (node-component node) :maybe)
-                     (return-from cut-node t))))
-               (when (and (not (block-delete-p (node-block node)))
-                          (combination-p node)
-                          (eq (basic-combination-kind node) :known))
-                 (let* ((fun-ref (lvar-use (combination-fun node)))
-                        (fun-name (leaf-source-name (ref-leaf fun-ref)))
-                        (modular-fun (find-modular-version fun-name kind signedp width)))
-                   (when (and modular-fun
-                              (not (and (eq fun-name 'logand)
-                                        (csubtypep
-                                         (single-value-type (node-derived-type node))
-                                         type))))
-                     (binding* ((name (etypecase modular-fun
-                                        ((eql :good) fun-name)
-                                        (modular-fun-info
-                                         (modular-fun-info-name modular-fun))
-                                        (function
-                                         (funcall modular-fun node width)))
-                                      :exit-if-null))
-                               (unless (eql modular-fun :good)
-                                 (setq did-something t)
-                                 (change-ref-leaf
-                                  fun-ref
-                                  (find-free-fun name "in a strange place"))
-                                 (setf (combination-kind node) :full))
-                               (unless (functionp modular-fun)
-                                 (dolist (arg (basic-combination-args node))
-                                   (when (cut-lvar arg)
-                                     (setq did-something t))))
-                               (when did-something
-                                 (reoptimize-node node name))
-                               did-something)))))
-             (cut-lvar (lvar &aux did-something)
+               "Try to cut a node to width. The primary return value is
+                whether we managed to cut (cleverly), and the second whether
+                anything was changed."
+               (when (block-delete-p (node-block node))
+                 (return-from cut-node (values t nil)))
+               (typecase node
+                 (ref
+                  (typecase (ref-leaf node)
+                    (constant
+                     (let* ((constant-value (constant-value (ref-leaf node)))
+                            (new-value (if signedp
+                                           (mask-signed-field width constant-value)
+                                           (ldb (byte width 0) constant-value))))
+                       (cond ((= constant-value new-value)
+                              (values t nil)) ; we knew what to do and did nothing
+                             (t
+                              (change-ref-leaf node (make-constant new-value)
+                                               :recklessly t)
+                              (let ((lvar (node-lvar node)))
+                                (setf (lvar-%derived-type lvar)
+                                      (and (lvar-has-single-use-p lvar)
+                                           (make-values-type :required (list (ctype-of new-value))))))
+                              (setf (block-reoptimize (node-block node)) t)
+                              (reoptimize-component (node-component node) :maybe)
+                              (values t t)))))))
+                 (combination
+                  (when (eq (basic-combination-kind node) :known)
+                    (let* ((fun-ref (lvar-use (combination-fun node)))
+                           (fun-name (lvar-fun-name (combination-fun node)))
+                           (modular-fun (find-modular-version fun-name kind
+                                                              signedp width)))
+                      (when (and modular-fun
+                                 (not (and (eq fun-name 'logand)
+                                           (csubtypep
+                                            (single-value-type (node-derived-type node))
+                                            type))))
+                        (binding* ((name (etypecase modular-fun
+                                           ((eql :good) fun-name)
+                                           (modular-fun-info
+                                            (modular-fun-info-name modular-fun))
+                                           (function
+                                            (funcall modular-fun node width)))
+                                         :exit-if-null))
+                          (unless (eql modular-fun :good)
+                            (setq did-something t)
+                            (change-ref-leaf
+                             fun-ref
+                             (find-free-fun name "in a strange place"))
+                            (setf (combination-kind node) :full))
+                          (unless (functionp modular-fun)
+                            (dolist (arg (basic-combination-args node))
+                              (when (cut-lvar arg)
+                                (setq did-something t))))
+                          (when did-something
+                            (reoptimize-node node name))
+                          (values t did-something))))))))
+             (cut-lvar (lvar &aux did-something must-insert)
+               "Cut all the LVAR's use nodes. If any of them wasn't handled
+                and its type is too wide for the operation we wish to perform
+                insert an explicit bit-width narrowing operation (LOGAND or
+                MASK-SIGNED-FIELD) between the LVAR (*) and its destination.
+                The narrowing operation might not be inserted if the LVAR's
+                destination is already such an operation, to avoid endless
+                recursion.
+
+                (*) We can't easily do that for each node, and doing so might
+                result in code bloat, anyway. (I'm also not sure it would be
+                correct for complicated C/D FG)"
                (do-uses (node lvar)
-                 (when (cut-node node)
-                   (setq did-something t)))
+                 (multiple-value-bind (handled any-change)
+                     (cut-node node)
+                   (setf did-something (or did-something any-change)
+                         must-insert (or must-insert
+                                         (not (or handled
+                                                  (csubtypep (single-value-type
+                                                              (node-derived-type node))
+                                                             type)))))))
+               (when must-insert
+                 (setf did-something (or (insert-lvar-cut lvar) did-something)))
                did-something))
       (cut-lvar lvar))))
 
@@ -3184,11 +3107,11 @@
   (if (and (constant-lvar-p x)
            (not (constant-lvar-p y)))
       `(,(lvar-fun-name (basic-combination-fun node))
-        y
+        (truly-the ,(lvar-type y) y)
         ,(lvar-value x))
       (give-up-ir1-transform)))
 
-(dolist (x '(= char= + * logior logand logxor))
+(dolist (x '(= char= + * logior logand logxor logtest))
   (%deftransform x '(function * *) #'commutative-arg-swap
                  "place constant arg last"))
 
@@ -3464,6 +3387,60 @@
       (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
+;;; probably be handled with a more general tree-rewriting pass.
+(macrolet ((def (operator &key (type 'integer) (folded operator))
+             `(deftransform ,operator ((x z) (,type (constant-arg ,type)))
+                ,(format nil "associate ~A/~A of constants"
+                         operator folded)
+                (binding* ((node  (if (lvar-has-single-use-p x)
+                                      (lvar-use x)
+                                      (give-up-ir1-transform)))
+                           (nil (or (and (combination-p node)
+                                         (eq (lvar-fun-name
+                                              (combination-fun node))
+                                             ',folded))
+                                    (give-up-ir1-transform)))
+                           (y   (second (combination-args node)))
+                           (nil (or (constant-lvar-p y)
+                                    (give-up-ir1-transform)))
+                           (y   (lvar-value y)))
+                  (unless (typep y ',type)
+                    (give-up-ir1-transform))
+                  (splice-fun-args x ',folded 2)
+                  `(lambda (x y z)
+                     (declare (ignore y z))
+                     (,',operator x ',(,folded y (lvar-value z))))))))
+  (def logand)
+  (def logior)
+  (def logxor)
+  (def logtest :folded logand)
+  (def + :type rational)
+  (def * :type rational))
+
+(deftransform mask-signed-field ((width x) ((constant-arg unsigned-byte) *))
+  "Fold mask-signed-field/mask-signed-field of constant width"
+  (binding* ((node  (if (lvar-has-single-use-p x)
+                        (lvar-use x)
+                        (give-up-ir1-transform)))
+             (nil (or (combination-p node)
+                      (give-up-ir1-transform)))
+             (nil (or (eq (lvar-fun-name (combination-fun node))
+                          'mask-signed-field)
+                      (give-up-ir1-transform)))
+             (x-width (first (combination-args node)))
+             (nil (or (constant-lvar-p x-width)
+                      (give-up-ir1-transform)))
+             (x-width (lvar-value x-width)))
+    (unless (typep x-width 'unsigned-byte)
+      (give-up-ir1-transform))
+    (splice-fun-args x 'mask-signed-field 2)
+    `(lambda (width x-width x)
+       (declare (ignore width x-width))
+       (mask-signed-field ,(min (lvar-value width) x-width) x))))
+
 ;;; These are restricted to rationals, because (- 0 0.0) is 0.0, not -0.0, and
 ;;; (* 0 -4.0) is -0.0.
 (deftransform - ((x y) ((constant-arg (member 0)) rational) *)
@@ -3473,6 +3450,25 @@
   "convert (* x 0) to 0"
   0)
 
+(deftransform %negate ((x) (rational))
+  "Eliminate %negate/%negate of rationals"
+  (splice-fun-args x '%negate 1)
+  '(the rational x))
+
+(deftransform %negate ((x) (number))
+  "Combine %negate/*"
+  (let ((use (lvar-uses x))
+        arg)
+    (unless (and (combination-p use)
+                 (eql '* (lvar-fun-name (combination-fun use)))
+                 (constant-lvar-p (setf arg (second (combination-args use))))
+                 (numberp (setf arg (lvar-value arg))))
+      (give-up-ir1-transform))
+    (splice-fun-args x '* 2)
+    `(lambda (x y)
+       (declare (ignore y))
+       (* x ,(- arg)))))
+
 ;;; Return T if in an arithmetic op including lvars X and Y, the
 ;;; result type is not affected by the type of X. That is, Y is at
 ;;; least as contagious as X.
@@ -3715,10 +3711,10 @@
         ((and (csubtypep x-type char-type)
               (csubtypep y-type char-type))
          '(char= x y))
-        ((or (fixnum-type-p x-type) (fixnum-type-p y-type))
-         (commutative-arg-swap node))
         ((or (eq-comparable-type-p x-type) (eq-comparable-type-p y-type))
-         '(eq x y))
+         (if (and (constant-lvar-p x) (not (constant-lvar-p y)))
+             '(eq y x)
+             '(eq x y)))
         ((and (not (constant-lvar-p y))
               (or (constant-lvar-p x)
                   (and (csubtypep x-type y-type)
@@ -4683,3 +4679,35 @@
                (policy-quality-name-p (lvar-value quality-name)))
     (give-up-ir1-transform))
   '(%policy-quality policy quality-name))
+
+(deftransform encode-universal-time
+    ((second minute hour date month year &optional time-zone)
+     ((constant-arg (mod 60)) (constant-arg (mod 60))
+      (constant-arg (mod 24))
+      (constant-arg (integer 1 31))
+      (constant-arg (integer 1 12))
+      (constant-arg (integer 1899))
+      (constant-arg (rational -24 24))))
+  (let ((second (lvar-value second))
+        (minute (lvar-value minute))
+        (hour (lvar-value hour))
+        (date (lvar-value date))
+        (month (lvar-value month))
+        (year (lvar-value year))
+        (time-zone (lvar-value time-zone)))
+    (if (zerop (rem time-zone 1/3600))
+        (encode-universal-time second minute hour date month year time-zone)
+        (give-up-ir1-transform))))
+
+#!-(and win32 (not sb-thread))
+(deftransform sleep ((seconds) ((integer 0 #.(expt 10 8))))
+  `(sb!unix:nanosleep seconds 0))
+
+#!-(and win32 (not sb-thread))
+(deftransform sleep ((seconds) ((constant-arg (real 0))))
+  (let ((seconds-value (lvar-value seconds)))
+    (multiple-value-bind (seconds nano)
+        (sb!impl::split-seconds-for-sleep seconds-value)
+      (if (> seconds (expt 10 8))
+          (give-up-ir1-transform)
+          `(sb!unix:nanosleep ,seconds ,nano)))))