Add more self-tests for 'hash_map' with Value type with non-trivial constructor/destructor (was: Expensive selftests)

[Thomas Schwinge]

Hi!

On 2021-08-17T10:57:36+0200, Richard Biener <richard.guenther@gmail.com> wrote:
> On Tue, Aug 17, 2021 at 8:40 AM Thomas Schwinge <thomas@codesourcery.com> wrote:
>> On 2021-08-16T14:10:00-0600, Martin Sebor <msebor@gmail.com> wrote:
>> > On 8/16/21 6:44 AM, Thomas Schwinge wrote:
>> >> [...], to document the current behavior, I propose to
>> >> "Add more self-tests for 'hash_map' with Value type with non-trivial
>> >> constructor/destructor", see attached.  OK to push to master branch?
>> >> (Also cherry-pick into release branches, eventually?)

>> > Adding more tests sounds like an excellent idea.  I'm not sure about
>> > the idea of adding loopy selftests that iterate as many times as in
>> > the patch (looks like 1234 times two?)
>>
>> Correct, and I agree it's a sensible concern, generally.
>>
>> The current 1234 times two iterations is really arbitrary (should
>> document that in the test case), just so that we trigger a few hash table
>> expansions.
>
> You could lower N_init (the default init is just 13!),
> even with just 128 inserted elements you'll trigger
> expansions to 31, 61 and 127 elements.

> I think the test is OK but it's also reasonable to lower
> the '1234' times and add a comment as to the count should
> trigger hashtable expansions "a few times".

Did that as follows:

    /* Verify basic construction and destruction of Value objects.  */
    {
      /* Configure, arbitrary.  */
      const size_t N_init = 0;
      const int N_elem = 28;

..., and:

    /* Verify aspects of 'hash_table::expand'.  */

    static void
    test_map_of_type_with_ctor_and_dtor_expand (bool remove_some_inline)
    {
      /* Configure, so that hash table expansion triggers a few times.  */
      const size_t N_init = 0;
      const int N_elem = 70;
      size_t expand_c_expected = 4;
    [...]
          if (expand)
        {
          ++expand_c;
    [...]
      ASSERT_EQ (expand_c, expand_c_expected);

Given that it's all deterministic (as far as I can tell...), we may
verify an exact number of hash table expansions.

Pushed "Add more self-tests for 'hash_map' with Value type with
non-trivial constructor/destructor" to master branch in commit
e4f16e9f357a38ec702fb69a0ffab9d292a6af9b, see attached.


Grüße
 Thomas


-----------------
Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße 201, 80634 München; Gesellschaft mit beschränkter Haftung; Geschäftsführer: Thomas Heurung, Frank Thürauf; Sitz der Gesellschaft: München; Registergericht München, HRB 106955
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-Add-more-self-tests-for-hash_map-with-Value-type-wit.patch
Type: text/x-diff
Size: 5253 bytes
Desc: not available
URL: <https://gcc.gnu.org/pipermail/gcc/attachments/20210818/ac2e61bc/attachment-0001.bin>