X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcompiler%2Fx86-64%2Farith.lisp;h=f455bff84d19ce993595c7af6e5581de0abdc75d;hb=69e6aef5e6fb3bd682c7a2cbf774034d2ea58ee8;hp=c50e0ddb13ae9d04571fd891fff1afb8dfca804a;hpb=dacd3fc70cf2fc78677f9a8bbbb5c3b51883f1b7;p=sbcl.git

diff --git a/src/compiler/x86-64/arith.lisp b/src/compiler/x86-64/arith.lisp
index c50e0dd..f455bff 100644
--- a/src/compiler/x86-64/arith.lisp
+++ b/src/compiler/x86-64/arith.lisp
@@ -1328,13 +1328,17 @@ constant shift greater than word length")))
                         (:translate ,tran)
                         (:conditional ,(if signed cond unsigned))
                         (:generator ,cost
-                                    (inst cmp x
-                                          ,(case suffix
-                                             (-c/fixnum
-                                                `(constantize (fixnumize y)))
-                                             ((-c/signed -c/unsigned)
-                                                `(constantize y))
-                                             (t 'y))))))
+                          (cond ((and (sc-is x any-reg signed-reg unsigned-reg)
+                                      (eql y 0))
+                                 (inst test x x))
+                                (t
+                                 (inst cmp x
+                                       ,(case suffix
+                                          (-c/fixnum
+                                           `(constantize (fixnumize y)))
+                                          ((-c/signed -c/unsigned)
+                                           `(constantize y))
+                                          (t 'y))))))))
                    '(/fixnum -c/fixnum /signed -c/signed /unsigned -c/unsigned)
 ;                  '(/fixnum  /signed  /unsigned)
                    '(4 3 6 5 6 5)