X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcompiler%2Fcopyprop.lisp;h=eefacbdd397e18ecdd76294f5ebc8b162e2d4a3f;hb=6a9bbe6f36179cee92001a1f9ed5ff38be512644;hp=41f886c6911a0ed68e537e4f729f9681cf5d8694;hpb=9f926721993baa5711eaf00d7c314924f269f3d2;p=sbcl.git

diff --git a/src/compiler/copyprop.lisp b/src/compiler/copyprop.lisp
index 41f886c..eefacbd 100644
--- a/src/compiler/copyprop.lisp
+++ b/src/compiler/copyprop.lisp
@@ -55,8 +55,8 @@
 ;;; The TN must be a :NORMAL TN. Other TNs might have hidden
 ;;; references or be otherwise bizarre.
 ;;;
-;;; A TN is also inelegible if it has interned name, policy is such
-;;; that we would dump it in the debug vars, and speed is not 3.
+;;; A TN is also inelegible if we want to preserve it to facilitate
+;;; debugging.
 ;;;
 ;;; The SCs of the TN's primitive types is a subset of the SCs of the
 ;;; copied TN. Moves between TNs of different primitive type SCs may
@@ -84,14 +84,22 @@
 				 (tn-primitive-type arg-tn)))
 		       (let ((leaf (tn-leaf tn)))
 			 (or (not leaf)
-			     (not (symbol-package (leaf-name leaf)))
-			     (policy (vop-node vop)
-				     (or (= speed 3) (< debug 2)))))
+                             (and
+                              ;; Do we not care about preserving this this
+                              ;; TN for debugging?
+                              (or
+                               (not (symbol-package (leaf-debug-name leaf)))
+                               (policy (vop-node vop)
+                                       (or (= speed 3) (< debug 2))))
+                              ;; arguments of local functions have hidden write
+                              (not (and (lambda-var-p leaf)
+                                        (memq (functional-kind (lambda-var-home leaf))
+                                                   '(nil :optional)))))))
 		       arg-tn)))))))
 
-;;; Init the sets in Block for copy propagation. To find Gen, we just
+;;; Init the sets in BLOCK for copy propagation. To find GEN, we just
 ;;; look for MOVE vops, and then see whether the result is a eligible
-;;; copy TN. To find Kill, we must look at all VOP results, seeing
+;;; copy TN. To find KILL, we must look at all VOP results, seeing
 ;;; whether any of the reads of the written TN are copies for eligible
 ;;; TNs.
 (defun init-copy-sets (block)
@@ -105,8 +113,9 @@
 		     (when (tn-is-copy-of y)
 		       (sset-adjoin y gen)
 		       t)))
+        ;; WANTED: explanation of UNLESS above.
 	(do ((res (vop-results vop) (tn-ref-across res)))
-	    ((null res))
+	    ((not res))
 	  (let ((res-tn (tn-ref-tn res)))
 	    (do ((read (tn-reads res-tn) (tn-ref-next read)))
 		((null read))
@@ -116,13 +125,12 @@
 		    (when (tn-is-copy-of y)
 		      (sset-delete y gen)
 		      (sset-adjoin y kill))))))))))
-
     (setf (block-out block) (copy-sset gen))
     (setf (block-kill block) kill)
     (setf (block-gen block) gen))
   (values))
 
-;;; Do the flow analysis step for copy propagation on Block. We rely
+;;; Do the flow analysis step for copy propagation on BLOCK. We rely
 ;;; on OUT being initialized to GEN, and use SSET-UNION-OF-DIFFERENCE
 ;;; to incrementally build the union in OUT, rather than replacing OUT
 ;;; each time.
@@ -133,7 +141,9 @@
     (dolist (pred-block (rest pred))
       (sset-intersection in (block-out pred-block)))
     (setf (block-in block) in)
-    (sset-union-of-difference (block-out block) in (block-kill block))))
+    (sset-union-of-difference (block-out block)
+			      in
+			      (block-kill block))))
 
 (defevent copy-deleted-move "Copy propagation deleted a move.")