merge revision(s) 49376,49387,49389: [Backport #10761]

	* st.c (st_numhash): mix float value for flonum

	* hash.c (rb_any_hash): ditto

	* benchmark/bm_hash_aref_flo.rb: new benchmark

	* benchmark/bm_hash_ident_flo.rb: ditto
	  [Bug #10761]

	* benchmark/bm_marshal_dump_flo.rb: new benchmark for [Bug #10761]

	* marshal.c (w_object, marshal_dump): use indetity tables for
	  arbitrary VALUE keys, because of performance of FLONUM.
	  [Bug #10761]

	* marshal.c (obj_alloc_by_klass, marshal_load): ditto.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_2@49513 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 9 insertions, 0 deletions

diff --git a/st.c b/st.c
index b7f66d08b4..e630c1ec48 100644
--- a/st.c
+++ b/st.c
@@ -1761,6 +1761,15 @@ st_numhash(st_data_t n)
      * - (n << 3) was finally added to avoid losing bits for fixnums
      * - avoid expensive modulo instructions, it is currently only
      *   shifts and bitmask operations.
+     * - flonum (on 64-bit) is pathologically bad, mix the actual
+     *   float value in, but do not use the float value as-is since
+     *   many integers get interpreted as 2.0 or -2.0 [Bug #10761]
      */
+#ifdef USE_FLONUM /* RUBY */
+    if (FLONUM_P(n)) {
+	n ^= (st_data_t)rb_float_value(n);
+    }
+#endif
+
     return (st_index_t)((n>>(RUBY_SPECIAL_SHIFT+3)|(n<<3)) ^ (n>>3));
 }