[Guile-commits] GNU Guile branch, stable-2.0, updated. v2.0.9-89-g8df6889

[Mark H Weaver]

This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "GNU Guile".

http://git.savannah.gnu.org/cgit/guile.git/commit/?id=8df68898b9f6ba15171244f1f3549688f13d605f

The branch, stable-2.0 has been updated
       via  8df68898b9f6ba15171244f1f3549688f13d605f (commit)
      from  84af582d1e9b5f04270d263a89aaa844750177d3 (commit)

Those revisions listed above that are new to this repository have
not appeared on any other notification email; so we list those
revisions in full, below.

- Log -----------------------------------------------------------------
commit 8df68898b9f6ba15171244f1f3549688f13d605f
Author: Mark H Weaver <address@hidden>
Date:   Thu Oct 3 14:25:51 2013 -0400

    Fix edge case in 'ash'.
    
    * libguile/numbers.c (scm_ash): Fix (ash -1 SCM_I_FIXNUM_BIT-1) to
      return a fixnum instead of a bignum.
    
    * test-suite/tests/numbers.test (ash): Add tests.

-----------------------------------------------------------------------

Summary of changes:
 libguile/numbers.c            |   11 +++++++----
 test-suite/tests/numbers.test |    8 +++++++-
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/libguile/numbers.c b/libguile/numbers.c
index 6f3a6ec..38c28a4 100644
--- a/libguile/numbers.c
+++ b/libguile/numbers.c
@@ -4978,11 +4978,14 @@ left_shift_exact_integer (SCM n, long count)
     {
       scm_t_inum nn = SCM_I_INUM (n);
 
-      /* Left shift of count >= SCM_I_FIXNUM_BIT-1 will always
+      /* Left shift of count >= SCM_I_FIXNUM_BIT-1 will almost[*] always
          overflow a non-zero fixnum.  For smaller shifts we check the
          bits going into positions above SCM_I_FIXNUM_BIT-1.  If they're
          all 0s for nn>=0, or all 1s for nn<0 then there's no overflow.
-         Those bits are "nn >> (SCM_I_FIXNUM_BIT-1 - count)".  */
+         Those bits are "nn >> (SCM_I_FIXNUM_BIT-1 - count)".
+
+         [*] There's one exception:
+             (-1) << SCM_I_FIXNUM_BIT-1 == SCM_MOST_NEGATIVE_FIXNUM  */
 
       if (nn == 0)
         return n;
@@ -4995,8 +4998,8 @@ left_shift_exact_integer (SCM n, long count)
           SCM result = scm_i_inum2big (nn);
           mpz_mul_2exp (SCM_I_BIG_MPZ (result), SCM_I_BIG_MPZ (result),
                         count);
-          return result;
-        }
+          return scm_i_normbig (result);
+       }
     }
   else if (SCM_BIGP (n))
     {
diff --git a/test-suite/tests/numbers.test b/test-suite/tests/numbers.test
index 68f8f91..16f06bf 100644
--- a/test-suite/tests/numbers.test
+++ b/test-suite/tests/numbers.test
@@ -5360,7 +5360,13 @@
 
       (for-each (lambda (n)
                   (for-each (lambda (count) (test n count))
-                            '(-1000 -3 -2 -1 0 1 2 3 1000)))
+                            `(-1000
+                              ,(- fixnum-bit)
+                              ,(- (- fixnum-bit 1))
+                              -3 -2 -1 0 1 2 3
+                              ,(- fixnum-bit 1)
+                              ,fixnum-bit
+                              1000)))
                 (list 0 1 3 23 -1 -3 -23
                       fixnum-max
                       (1+ fixnum-max)


hooks/post-receive
-- 
GNU Guile