[Sbcl-commits] CVS: sbcl/src/compiler/x86-64 arith.lisp,1.32,1.33

[Paul K. <pk...@us...>]

Update of /cvsroot/sbcl/sbcl/src/compiler/x86-64
In directory sfp-cvsdas-3.v30.ch3.sourceforge.com:/tmp/cvs-serv28853/src/compiler/x86-64

Modified Files:
	arith.lisp 
Log Message:
1.0.43.47: Unfix ASH of constant shift on x86oids

 * The fixnum=>fixnum VOPs for ASH used to explicitly handle shifts greater
   than the word length by computing a zero instead.  These should be 
   constant-folded away in IR1 now.

 * 1.0.43.45 incidentally fixed lp #309063 (which is what the fix above
   was used for). Add a test case, update NEWS, and note the optimizations
   committed in 1.0.43.{42,43,47}.


Index: arith.lisp
===================================================================
RCS file: /cvsroot/sbcl/sbcl/src/compiler/x86-64/arith.lisp,v
retrieving revision 1.32
retrieving revision 1.33
diff -u -d -r1.32 -r1.33
--- arith.lisp	17 Dec 2009 21:01:48 -0000	1.32
+++ arith.lisp	12 Oct 2010 05:10:07 -0000	1.33
@@ -667,6 +667,8 @@
                                        (location= number result)))))
   (:result-types tagged-num)
   (:note "inline ASH")
+  (:variant nil)
+  (:variant-vars modularp)
   (:generator 2
     (cond ((and (= amount 1) (not (location= number result)))
            (inst lea result (make-ea :qword :base number :index number)))
@@ -685,8 +687,11 @@
                         (inst sar result (- amount))
                         (inst and result (lognot fixnum-tag-mask)))))
                  ((plusp amount)
+                  (unless modularp
+                    (aver (not "Impossible: fixnum ASH should not be called with
+constant shift greater than word length")))
                   (if (sc-is result any-reg)
-                      (inst xor result result)
+                      (zeroize result)
                       (inst mov result 0)))
                  (t (inst sar result 63)
                     (inst and result (lognot fixnum-tag-mask))))))))
@@ -1367,6 +1372,7 @@
 
 (define-vop (fast-ash-left-smod61-c/fixnum=>fixnum
              fast-ash-c/fixnum=>fixnum)
+  (:variant :modular)
   (:translate ash-left-smod61))
 (define-vop (fast-ash-left-smod61/fixnum=>fixnum
              fast-ash-left/fixnum=>fixnum))