1.0.30.2: more aggressive constant-folding

[sbcl.git] / src / compiler / x86-64 / type-vops.lisp

diff --git a/src/compiler/x86-64/type-vops.lisp b/src/compiler/x86-64/type-vops.lisp
index 450a6a4..d8e49e0 100644 (file)
--- a/src/compiler/x86-64/type-vops.lisp
+++ b/src/compiler/x86-64/type-vops.lisp
@@ -20,7 +20,7 @@
                (make-byte-tn value))
               ((sc-is value control-stack)
                (make-ea :byte :base rbp-tn
-                        :disp (- (* (1+ (tn-offset value)) n-word-bytes))))
+                        :disp (frame-byte-offset (tn-offset value))))
               (t
                value))
         sb!vm::fixnum-tag-mask))
@@ -184,10 +184,27 @@
   (:arg-types unsigned-num)
   (:translate fixnump)
   (:temporary (:sc unsigned-reg) tmp)
+  (:info)
+  (:conditional :z)
   (:generator 5
     (inst mov tmp value)
-    (inst shr tmp n-positive-fixnum-bits)
-    (inst jmp (if not-p :nz :z) target)))
+    (inst shr tmp n-positive-fixnum-bits)))
+
+(define-vop (fixnump/signed-byte-64 type-predicate)
+  (:args (value :scs (signed-reg)))
+  (:info)
+  (:conditional :z)
+  (:arg-types signed-num)
+  (:translate fixnump)
+  (:generator 5
+    ;; Hackers Delight, p. 53: signed
+    ;;    a <= x <= a + 2^n - 1
+    ;; is equivalent to unsigned
+    ;;    ((x-a) >> n) = 0
+    (inst mov rax-tn #.(- sb!xc:most-negative-fixnum))
+    (inst add rax-tn value)
+    (inst shr rax-tn #.(integer-length (- sb!xc:most-positive-fixnum
+                                          sb!xc:most-negative-fixnum)))))
 
 ;;; A (SIGNED-BYTE 64) can be represented with either fixnum or a bignum with
 ;;; exactly one digit.