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fix flonum hashing regression from r45384

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* 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
This commit is contained in:
normal 2015-01-22 07:48:59 +00:00
parent c73f2d28b4
commit 6d56fd067e
5 changed files with 32 additions and 1 deletions
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8
ChangeLog
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@ -1,3 +1,11 @@
Thu Jan 22 16:45:24 2015 Eric Wong <e@80x24.org>
* 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]
Wed Jan 21 22:33:51 2015 Akinori MUSHA <knu@iDaemons.org>
* misc/ruby-electric.el: Import version 2.2.1 from

4
benchmark/bm_hash_aref_flo.rb Normal file
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@ -0,0 +1,4 @@
h = {}
strs = (1..10000).to_a.map!(&:to_f)
strs.each { |s| h[s] = s }
50.times { strs.each { |s| h[s] } }

4
benchmark/bm_hash_ident_flo.rb Normal file
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@ -0,0 +1,4 @@
h = {}.compare_by_identity
strs = (1..10000).to_a.map!(&:to_f)
strs.each { |s| h[s] = s }
50.times { strs.each { |s| h[s] } }

8
hash.c
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@ -137,7 +137,13 @@ rb_any_hash(VALUE a)
if (SPECIAL_CONST_P(a)) {
if (a == Qundef) return 0;
if (STATIC_SYM_P(a)) a >>= (RUBY_SPECIAL_SHIFT + ID_SCOPE_SHIFT);
if (STATIC_SYM_P(a)) {
a >>= (RUBY_SPECIAL_SHIFT + ID_SCOPE_SHIFT);
}
else if (FLONUM_P(a)) {
/* prevent pathological behavior: [Bug #10761] */
a = (st_index_t)rb_float_value(a);
}
hnum = rb_objid_hash((st_index_t)a);
}
else if (BUILTIN_TYPE(a) == T_STRING) {

9
st.c
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@ -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));
}