X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcompiler%2Fsrctran.lisp;h=e13c30e019e7799ab08cf50a3f42b4620e683ba5;hb=1daa58cfa315fe86634069c941cf54ec8f95623c;hp=298c8a6b8e8e6ae8a6615d5a5045e1ab84c697e1;hpb=423b1f8cba83d16e57e852a51cf5d51ef709b2ed;p=sbcl.git

diff --git a/src/compiler/srctran.lisp b/src/compiler/srctran.lisp
index 298c8a6..e13c30e 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)
@@ -2686,7 +2764,98 @@
               (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))
+    "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)))
+      (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))
+    "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)))
+      (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
 
@@ -2751,58 +2920,121 @@
                (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))))
 
@@ -2830,53 +3062,85 @@
           (return-from best-modular-version
             (values (car ugt) :untagged (cdr ugt))))))))
 
+(defun integer-type-numeric-bounds (type)
+  (typecase type
+    (numeric-type (values (numeric-type-low type)
+                          (numeric-type-high type)))
+    (union-type
+     (let ((low  nil)
+           (high nil))
+       (dolist (type (union-type-types type) (values low high))
+         (unless (and (numeric-type-p type)
+                      (eql (numeric-type-class type) 'integer))
+           (return (values nil nil)))
+         (let ((this-low (numeric-type-low type))
+               (this-high (numeric-type-high type)))
+           (setf low  (min this-low  (or low  this-low))
+                 high (max this-high (or high this-high)))))))))
+
 (defoptimizer (logand optimizer) ((x y) node)
   (let ((result-type (single-value-type (node-derived-type node))))
-    (when (numeric-type-p result-type)
-      (let ((low (numeric-type-low result-type))
-            (high (numeric-type-high result-type)))
-        (when (and (numberp low)
-                   (numberp high)
-                   (>= low 0))
-          (let ((width (integer-length high)))
-            (multiple-value-bind (w kind signedp)
-                (best-modular-version width nil)
-              (when w
-                ;; FIXME: This should be (CUT-TO-WIDTH NODE KIND WIDTH SIGNEDP).
-                ;;
-                ;; FIXME: I think the FIXME (which is from APD) above
-                ;; implies that CUT-TO-WIDTH should do /everything/
-                ;; that's required, including reoptimizing things
-                ;; itself that it knows are necessary.  At the moment,
-                ;; CUT-TO-WIDTH sets up some new calls with
-                ;; combination-type :FULL, which later get noticed as
-                ;; known functions and properly converted.
-                ;;
-                ;; We cut to W not WIDTH if SIGNEDP is true, because
-                ;; signed constant replacement needs to know which bit
-                ;; in the field is the signed bit.
-                (let ((xact (cut-to-width x kind (if signedp w width) signedp))
-                      (yact (cut-to-width y kind (if signedp w width) signedp)))
-                  (declare (ignore xact yact))
-                  nil) ; After fixing above, replace with T, meaning
-                       ; "don't reoptimize this (LOGAND) node any more".
-                ))))))))
+    (multiple-value-bind (low high)
+        (integer-type-numeric-bounds result-type)
+      (when (and (numberp low)
+                 (numberp high)
+                 (>= low 0))
+        (let ((width (integer-length high)))
+          (multiple-value-bind (w kind signedp)
+              (best-modular-version width nil)
+            (when w
+              ;; FIXME: This should be (CUT-TO-WIDTH NODE KIND WIDTH SIGNEDP).
+              ;;
+              ;; FIXME: I think the FIXME (which is from APD) above
+              ;; implies that CUT-TO-WIDTH should do /everything/
+              ;; that's required, including reoptimizing things
+              ;; itself that it knows are necessary.  At the moment,
+              ;; CUT-TO-WIDTH sets up some new calls with
+              ;; combination-type :FULL, which later get noticed as
+              ;; known functions and properly converted.
+              ;;
+              ;; We cut to W not WIDTH if SIGNEDP is true, because
+              ;; signed constant replacement needs to know which bit
+              ;; in the field is the signed bit.
+              (let ((xact (cut-to-width x kind (if signedp w width) signedp))
+                    (yact (cut-to-width y kind (if signedp w width) signedp)))
+                (declare (ignore xact yact))
+                nil) ; After fixing above, replace with T, meaning
+                                        ; "don't reoptimize this (LOGAND) node any more".
+              )))))))
 
 (defoptimizer (mask-signed-field optimizer) ((width x) node)
   (let ((result-type (single-value-type (node-derived-type node))))
-    (when (numeric-type-p result-type)
-      (let ((low (numeric-type-low result-type))
-            (high (numeric-type-high result-type)))
-        (when (and (numberp low) (numberp high))
-          (let ((width (max (integer-length high) (integer-length low))))
-            (multiple-value-bind (w kind)
-                (best-modular-version (1+ width) t)
-              (when w
-                ;; FIXME: This should be (CUT-TO-WIDTH NODE KIND W T).
-                ;; [ see comment above in LOGAND optimizer ]
-                (cut-to-width x kind w t)
-                nil ; After fixing above, replace with T.
-                ))))))))
+    (multiple-value-bind (low high)
+        (integer-type-numeric-bounds result-type)
+      (when (and (numberp low) (numberp high))
+        (let ((width (max (integer-length high) (integer-length low))))
+          (multiple-value-bind (w kind)
+              (best-modular-version (1+ width) t)
+            (when w
+              ;; FIXME: This should be (CUT-TO-WIDTH NODE KIND W T).
+              ;; [ see comment above in LOGAND optimizer ]
+              (cut-to-width x kind w t)
+              nil                ; After fixing above, replace with T.
+              )))))))
+
+(defoptimizer (logior optimizer) ((x y) node)
+  (let ((result-type (single-value-type (node-derived-type node))))
+    (multiple-value-bind (low high)
+        (integer-type-numeric-bounds result-type)
+      (when (and (numberp low)
+                 (numberp high)
+                 (<= high 0))
+        (let ((width (integer-length low)))
+          (multiple-value-bind (w kind)
+              (best-modular-version (1+ width) t)
+            (when w
+              ;; FIXME: see comment in LOGAND optimizer
+              (let ((xact (cut-to-width x kind w t))
+                    (yact (cut-to-width y kind w t)))
+                (declare (ignore xact yact))
+                nil) ; After fixing above, replace with T
+              )))))))
 
 ;;; miscellanous numeric transforms
 
@@ -2885,11 +3149,11 @@
   (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"))
 
@@ -3147,14 +3411,17 @@
   (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))
 
@@ -3165,6 +3432,74 @@
       (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
+;;; 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 (folded x y) z)
+                     ;; == (operator x (folded z y))
+                     (,',operator x ',(,folded (lvar-value z) y)))))))
+  (def logand)
+  (def logior)
+  (def logxor)
+  (def logtest :folded logand)
+  (def + :type rational)
+  (def + :type rational :folded -)
+  (def * :type rational)
+  (def * :type rational :folded /))
+
+(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) *)
@@ -3174,6 +3509,25 @@
   "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.
@@ -3416,10 +3770,10 @@
         ((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)
@@ -4384,3 +4738,35 @@
                (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)))))