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authornormal <normal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2015-01-22 07:48:59 +0000
committernormal <normal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2015-01-22 07:48:59 +0000
commit6d56fd067e219803e194b8b95aa00e558250cfec (patch)
tree71c35bf49f4f6b817ce34af7e8c419031c263405 /st.c
parentc73f2d28b41a532a71b9b5000d0d59a4c6f49a91 (diff)
downloadruby-6d56fd067e219803e194b8b95aa00e558250cfec.tar.gz
fix flonum hashing regression from r45384
* 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] git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49376 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'st.c')
-rw-r--r--st.c9
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));
}