X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=OPTIMIZATIONS;h=2b2d63b5b69e118fd53ef28c2f876758fefc5a7f;hb=98f3f617894ce24a40764aa98606ce68c5482cf0;hp=7f45bee38b0cde660fe092d60e25efa307a9fb07;hpb=852a4504e8a9040adf52d374dafa4813bc661173;p=sbcl.git

diff --git a/OPTIMIZATIONS b/OPTIMIZATIONS
index 7f45bee..2b2d63b 100644
--- a/OPTIMIZATIONS
+++ b/OPTIMIZATIONS
@@ -1,3 +1,4 @@
+#1
 (defun mysl (s)
     (declare (simple-string s))
     (declare (optimize (speed 3) (safety 0) (debug 0)))
@@ -18,6 +19,7 @@
   4: MOVE t23[EAX] => t24[EBX]
 
 --------------------------------------------------------------------------------
+#2
 (defun quux (v)
   (declare (optimize (speed 3) (safety 0) (space 2) (debug 0)))
   (declare (type (simple-array double-float 1) v))
@@ -34,6 +36,7 @@
   and emits costy MOVE ... => FR1.
 
 --------------------------------------------------------------------------------
+#3
 (defun bar (n)
   (declare (optimize (speed 3) (safety 0) (space 2))
            (type fixnum n))
@@ -42,10 +45,8 @@
     (length v)))
 
 * IR1 does not optimize away (MAKE-LIST N).
-
-* IR1 thinks that the type of V in (LENGTH V) is (OR LIST SIMPLE-VECTOR), not
-  SIMPLE-VECTOR.
 --------------------------------------------------------------------------------
+#4
 (defun bar (v1 v2)
   (declare (optimize (speed 3) (safety 0) (space 2))
            (type (simple-array base-char 1) v1 v2))
@@ -64,10 +65,12 @@ VOP DATA-VECTOR-SET/SIMPLE-STRING V2!14[EDI] t32[EAX] t30[S2]>t33[CL]
 
 * And why two moves?
 --------------------------------------------------------------------------------
+#5
 (loop repeat 1.5)
 
 uses generic arithmetic
 --------------------------------------------------------------------------------
+#6
 09:49:05 <jtra> I have found a case in those where suboptimal code is
   generate with nested loops, it might be moderately easy to fix that
 09:49:28 <jtra> see
@@ -96,3 +99,73 @@ uses generic arithmetic
                 (incf x)))))))
    (format t "~A~%" x)))
 --------------------------------------------------------------------------------
+#7
+(defun foo (x)
+  (declare (optimize speed (debug 0)))
+  (if (< x 0) x (foo (1- x))))
+
+SBCL generates a full call of FOO (but CMUCL does not).
+--------------------------------------------------------------------------------
+#8
+(defun foo (d)
+  (declare (optimize (speed 3) (safety 0) (debug 0)))
+  (declare (type (double-float 0d0 1d0) d))
+  (loop for i fixnum from 1 to 5
+     for x1 double-float = (sin d) ;;; !!!
+     do (loop for j fixnum from 1 to 4
+             sum x1 double-float)))
+
+Without the marked declaration Python will use boxed representation for X1.
+
+This is equivalent to
+
+(let ((x nil))
+  (setq x 0d0)
+  ;; use of X as DOUBLE-FLOAT
+)
+
+The initial binding is effectless, and without it X is of type
+DOUBLE-FLOAT. Unhopefully, IR1 does not optimize away effectless
+SETs/bindings, and IR2 does not perform type inference.
+--------------------------------------------------------------------------------
+#9
+(defun foo (x)
+  (if (= (cond ((irgh x) 0)
+               ((buh x) 1)
+               (t 2))
+         0)
+      :yes
+      :no))
+
+This code could be optimized to
+
+(defun foo (x)
+  (cond ((irgh x) :yes)
+        ((buh x) :no)
+        (t :no)))
+--------------------------------------------------------------------------------
+#10
+Reported by Robert E. Brown on sbcl-devel 2003-01-21:
+
+(defstruct trace-info
+  (foo nil :type (or null function)))
+
+(defun bad (x)
+  (declare (optimize (speed 3) (safety 0)))
+  (let ((wow (trace-info-foo x)))
+    (or (not wow) (funcall wow 1 2 3))))
+
+Python does not derive that FUNCALL is applied to FUNCTION.
+
+(OR ...) is equivalent to
+
+(LET ((G2407 (NOT WOW)))
+  (IF G2407 G2407 (FUNCALL WOW 1 2 3)))
+
+or to
+
+(LET ((G2407 (IF WOW NIL T)))
+  (IF G2407 G2407 (FUNCALL WOW 1 2 3)))
+
+so this is similar to #9.
+--------------------------------------------------------------------------------