On 09/18/2018 10:41 AM, Jonathan Wakely wrote:
On 13/09/18 07:49 +0200, François Dumont wrote:
All changes limited to hashtable_c++0x.cc file.
_Prime_rehash_policy::_M_next_bkt now really does what its comment
was declaring that is to say:
// Return a prime no smaller than n.
_Prime_rehash_policy::_M_need_rehash rehash only when _M_next_size is
exceeded, not only when it is reach.
PR libstdc++/87135
* src/c++11/hashtable_c++0x.cc:
(_Prime_rehash_policy::_M_next_bkt): Return a prime no smaller than
requested size, but not necessarily greater.
(_Prime_rehash_policy::_M_need_rehash): Rehash only if target
size is
strictly greater than next resize threshold.
* testsuite/23_containers/unordered_map/modifiers/reserve.cc:
Adapt test
to validate that there is no rehash as long as number of
insertion is
lower or equal to the reserved number of elements.
unordered_map tests successful, ok to commit once all other tests
completed ?
François
diff --git a/libstdc++-v3/src/c++11/hashtable_c++0x.cc
b/libstdc++-v3/src/c++11/hashtable_c++0x.cc
index a776a8506fe..ec6031b3f5b 100644
--- a/libstdc++-v3/src/c++11/hashtable_c++0x.cc
+++ b/libstdc++-v3/src/c++11/hashtable_c++0x.cc
@@ -46,10 +46,10 @@ namespace __detail
{
// Optimize lookups involving the first elements of __prime_list.
// (useful to speed-up, eg, constructors)
- static const unsigned char __fast_bkt[13]
- = { 2, 2, 3, 5, 5, 7, 7, 11, 11, 11, 11, 13, 13 };
+ static const unsigned char __fast_bkt[]
+ = { 2, 2, 2, 3, 5, 5, 7, 7, 11, 11, 11, 11, 13, 13 };
- if (__n <= 12)
+ if (__n < sizeof(__fast_bkt) / sizeof(unsigned char))
sizeof(unsigned char) is defined to be 1, always.
I also though it was overkill but there are so many platforms that I
prefer to be caution. Good to know that it can't be otherwise.
I think this should be just sizeof(__fast_bkt), or if you're trying to
guard against the type of __fast_bkt changing, then use
sizeof(__fast_bkt) / sizeof(__fast_bkt[0]))
I committed with simply sizeof(__fast_bkt)
