better initial value for LOOP variables of-type CHARACTER

diff --git a/NEWS b/NEWS
index fb73ea8..1ccdb41 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,7 @@
 ;;;; -*- coding: utf-8; fill-column: 78 -*-
 changes relative to sbcl-1.1.3:
+  * optimization: LOOP expressions using "of-type character" have slightly
+    more efficient expansions.
   * bug fix: very long (or infinite) constant lists in DOLIST do not result
     in very long compile times or heap exhaustion anymore. (lp#1095488)
   * bug fix: `#3(1) is read as #(1 1 1), not as #(1). (lp#1095918)

diff --git a/src/code/loop.lisp b/src/code/loop.lisp
index e4ad5e9..726abee 100644 (file)
--- a/src/code/loop.lisp
+++ b/src/code/loop.lisp
@@ -925,6 +925,8 @@ code to be loaded.
              (let ((etype (sb!kernel:type-*-to-t
                            (sb!kernel:array-type-specialized-element-type ctype))))
                (make-array 0 :element-type (sb!kernel:type-specifier etype))))))
+        ((sb!xc:typep #\x data-type)
+         #\x)
         (t
          nil)))
 

diff --git a/tests/loop.pure.lisp b/tests/loop.pure.lisp
index 9e6a2db..5cd85f3 100644 (file)
--- a/tests/loop.pure.lisp
+++ b/tests/loop.pure.lisp
@@ -13,6 +13,8 @@
 
 (in-package "CL-USER")
 
+(load "compiler-test-util.lisp")
+
 ;;; The bug reported by Alexei Dejneka on sbcl-devel 2001-09-03
 ;;; is fixed now.
 (assert (equal (let ((hash (make-hash-table)))
@@ -273,3 +275,13 @@
   (assert (= 32640 (loop for i to 255
                          sum i into sum of-type fixnum
                          finally (return sum)))))
+
+(with-test (:name :of-type-character-init)
+  ;; The intention here is to if we initialize C to NIL before iteration start
+  ;; by looking for tell-tale types such as (OR NULL CHARACTER). ...not the
+  ;; most robust test ever, no.
+  (let* ((fun (compile nil `(lambda (x)
+                              (loop for c of-type character in x
+                                    collect (char-code c)))))
+         (consts (ctu:find-code-constants fun :type '(or symbol list))))
+    (assert (or (null consts) (equal 'character consts)))))