Loops returning primtives are boxed even in return position

Description

Reported here: https://groups.google.com/d/topic/clojure/atoFzbyuyos/discussion

(defn first-bit?
  {:inline (fn [n] `(== 1 (clojure.lang.Numbers/and ~n, 1)) )}
  [^long n]
  (== 1 (clojure.lang.Numbers/and n, 1)))

(defn exp-int
  ^double [^double x, ^long c]
  (loop [result 1.0, factor x, c c]
    (if (> c 0)
        (recur
         (if (first-bit? c)
           (* result factor)
           result),
         (* factor factor),
         (bit-shift-right c 1))
      result)))

Last lines of the Java bytecode of `exp-int`:

dload 5;               /* result */
invokestatic 40;       /* java.lang.Double java.lang.Double.valueOf(double c) */
checkcast 85;          /* java.lang.Number */
invokevirtual 89;      /* double doubleValue() */
dreturn;

The compiler doesn't currently infer the primitive type as soon as there is a recur:

(use '[clojure.contrib.repl-utils :only [expression-info]])
(expression-info '(loop [a 1] a))
;=> {:class long, :primitive? true}
(expression-info '(loop [a 1] (if true a (recur a)))
;=> nil

Patch attached.

Environment

None

Attachments

21 Nov 2012, 11:17 AM

Activity

Christophe Grand November 27, 2012 at 10:40 AM

FYI, gvec.clj has two loops which return primitives and thus was formerly boxed.

Timothy Baldridge November 26, 2012 at 4:59 PM

Tests also pass here. Looked through the code and played with a patched version of Clojure. I can't see a problem with it.

Stuart Halloway November 26, 2012 at 1:12 AM

Tests pass, code looks reasonable. Would appreciate additional review.

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Completed

Details

Assignee

Christophe Grand

Reporter

Christophe Grand

Approval

Patch

Code

Priority

Major

Affects versions

Release 1.4

Fix versions

Release 1.5

Created November 21, 2012 at 11:17 AM

Updated December 22, 2012 at 3:53 PM

Resolved December 22, 2012 at 3:53 PM