Hash table threshold is now float, not double

Change default from 0.8 to 0.8125 so it fits in float without
rounding glitches.
* doc/lispref/hash.texi (Creating Hash):
* doc/lispref/objects.texi (Hash Table Type):
* etc/NEWS:
Document change.
* src/fns.c (make_hash_table, maybe_resize_hash_table)
(Fmake_hash_table): Threshold is now float, not double.
Be consistent about how this is rounded.
* src/lisp.h (struct Lisp_Hash_Table.rehash_threshold):
Change back to float, now that the other code rounds consistently.
(DEFAULT_REHASH_THRESHOLD): Now float 0.8125 instead of double 0.8.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/lisp.h b/src/lisp.h
index be42b3354e2..6e0252621a6 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -2004,7 +2004,7 @@ struct Lisp_Hash_Table
 
   /* Resize hash table when number of entries / table size is >= this
      ratio.  */
-  double rehash_threshold;
+  float rehash_threshold;
 
   /* Vector of keys and values.  The key of item I is found at index
      2 * I, the value is found at index 2 * I + 1.
@@ -2088,7 +2088,7 @@ enum DEFAULT_HASH_SIZE { DEFAULT_HASH_SIZE = 65 };
    value gives the ratio of current entries in the hash table and the
    size of the hash table.  */
 
-static double const DEFAULT_REHASH_THRESHOLD = 0.8;
+static float const DEFAULT_REHASH_THRESHOLD = 0.8125;
 
 /* Default factor by which to increase the size of a hash table.  */
 
@@ -3363,7 +3363,7 @@ EMACS_UINT hash_string (char const *, ptrdiff_t);
 EMACS_UINT sxhash (Lisp_Object, int);
 Lisp_Object make_hash_table (struct hash_table_test test,
                              Lisp_Object size, Lisp_Object rehash_size,
-                             double rehash_threshold, Lisp_Object weak,
+                             float rehash_threshold, Lisp_Object weak,
                              bool pure);
 ptrdiff_t hash_lookup (struct Lisp_Hash_Table *, Lisp_Object, EMACS_UINT *);
 ptrdiff_t hash_put (struct Lisp_Hash_Table *, Lisp_Object, Lisp_Object,