1.0.37.38: micro-optimizations of CONCATENATE bits

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

diff --git a/src/compiler/x86/type-vops.lisp b/src/compiler/x86/type-vops.lisp
index 9d53fe9..1738be3 100644 (file)
--- a/src/compiler/x86/type-vops.lisp
+++ b/src/compiler/x86/type-vops.lisp
@@ -127,18 +127,28 @@
                      ;; was true.
                      (return))
                     (t
-                     (unless (= start bignum-widetag)
-                       (inst cmp al-tn start)
-                       (if (= end complex-array-widetag)
-                           (progn
-                             (aver last)
-                             (inst jmp greater-or-equal target))
-                           (inst jmp :b when-false))) ; was :l
-                     (unless (= end complex-array-widetag)
-                       (inst cmp al-tn end)
-                       (if last
-                           (inst jmp less-or-equal target)
-                           (inst jmp :be when-true)))))))))))) ; was :le
+                     (cond
+                       ((= start bignum-widetag)
+                        (inst cmp al-tn end)
+                        (if last
+                            (inst jmp less-or-equal target)
+                            (inst jmp :be when-true)))
+                       ((= end complex-array-widetag)
+                        (inst cmp al-tn start)
+                        (if last
+                            (inst jmp greater-or-equal target)
+                            (inst jmp :b when-false)))
+                       ((not last)
+                        (inst cmp al-tn start)
+                        (inst jmp :b when-false)
+                        (inst cmp al-tn end)
+                        (if last
+                            (inst jmp less-or-equal target)
+                            (inst jmp :be when-true)))
+                       (t
+                        (inst sub al-tn start)
+                        (inst cmp al-tn (- end start))
+                        (inst jmp less-or-equal target))))))))))))
       (emit-label drop-through))))
 \f
 ;;;; type checking and testing
@@ -212,8 +222,27 @@
   (:arg-types unsigned-num)
   (:translate fixnump)
   (:generator 5
+    ;; We could encode this with :Z and SHR, analogously to the signed-byte-32
+    ;; case below -- as we do on x86-64 -- but that costs us an extra
+    ;; register. Compromises...
     (inst cmp value #.sb!xc:most-positive-fixnum)))
 
+(define-vop (fixnump/signed-byte-32 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 eax-tn value)
+    (inst sub eax-tn #.sb!xc:most-negative-fixnum)
+    (inst shr eax-tn #.(integer-length (- sb!xc:most-positive-fixnum
+                                          sb!xc:most-negative-fixnum)))))
+
 ;;; A (SIGNED-BYTE 32) can be represented with either fixnum or a bignum with
 ;;; exactly one digit.