[Sbcl-commits] master: Micro-optimize vector creation.

[stassats <sta...@us...>]

The branch "master" has been updated in SBCL:
       via  1dff970a3514e323517d3ddd876821cc5e381d69 (commit)
      from  e527c3b0def320e81f321ce9094445714c47bed6 (commit)

- Log -----------------------------------------------------------------
commit 1dff970a3514e323517d3ddd876821cc5e381d69
Author: Stas Boukarev <sta...@gm...>
Date:   Sat Nov 30 20:12:22 2013 +0400

    Micro-optimize vector creation.
    
    transform-make-array-vector expanded into
    (allocate-vector typecode (the index length) (ceiling length x))
    but the transform applied to CEILING before it was known that LENGTH
    is of type INDEX was producing bad results,
    (ceiling (truly-the index length) x) solves that.
---
 src/compiler/array-tran.lisp |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/compiler/array-tran.lisp b/src/compiler/array-tran.lisp
index 3403ac3..14b2fa5 100644
--- a/src/compiler/array-tran.lisp
+++ b/src/compiler/array-tran.lisp
@@ -414,12 +414,13 @@
                   (t
                    (let ((n-elements-per-word (/ sb!vm:n-word-bits n-bits)))
                      (declare (type index n-elements-per-word)) ; i.e., not RATIO
-                     `(ceiling ,padded-length-form ,n-elements-per-word)))))))
+                     `(ceiling (truly-the index ,padded-length-form)
+                               ,n-elements-per-word)))))))
          (result-spec
           `(simple-array ,(sb!vm:saetp-specifier saetp) (,(or c-length '*))))
          (alloc-form
-          `(truly-the ,result-spec
-                      (allocate-vector ,typecode (the index length) ,n-words-form))))
+           `(truly-the ,result-spec
+                       (allocate-vector ,typecode (the index length) ,n-words-form))))
     (cond ((and initial-element initial-contents)
            (abort-ir1-transform "Both ~S and ~S specified."
                                 :initial-contents :initial-element))

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