Port modiff changes to GCC 4.8.5

Problem reported by Spencer Baugh.
* src/lisp.h (elogb): Now simply a function on unsigned long long int.
This avoids problems porting to GCC 4.8.5 20150623 (Red Hat 4.8.5-44).
There may be a minor runtime cost on 32-bit platforms but it’s
not worth worrying about.

1 files changed, 5 insertions, 12 deletions

diff --git a/src/lisp.h b/src/lisp.h
index c9a64f07427..57c1c7395c1 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -3906,18 +3906,11 @@ integer_to_uintmax (Lisp_Object num, uintmax_t *n)
 }
 
 /* Return floor (log2 (N)) as an int, where 0 < N <= ULLONG_MAX.  */
-#if (201112 <= __STDC_VERSION__ && INT_MAX <= UINT_MAX \
-     && LONG_MAX <= ULONG_MAX && LLONG_MAX <= ULLONG_MAX)
-# define elogb(n) \
-    _Generic (+(n), \
-              int:           UINT_WIDTH   - 1 - count_leading_zeros    (n), \
-              unsigned int:  UINT_WIDTH   - 1 - count_leading_zeros    (n), \
-              long:          ULONG_WIDTH  - 1 - count_leading_zeros_l  (n), \
-              unsigned long: ULONG_WIDTH  - 1 - count_leading_zeros_l  (n), \
-              default:       ULLONG_WIDTH - 1 - count_leading_zeros_ll (n))
-#else
-# define elogb(n) (ULLONG_WIDTH - 1 - count_leading_zeros_ll (n))
-#endif
+INLINE int
+elogb (unsigned long long int n)
+{
+  return ULLONG_WIDTH - 1 - count_leading_zeros_ll (n);
+}
 
 /* A modification count.  These are wide enough, and incremented
    rarely enough, so that they should never overflow a 60-bit counter