Make 'gcc/hash-map-tests.c:test_map_of_type_with_ctor_and_dtor_expand' work on 32-bit architectures [PR101959]

Thomas Schwinge thomas@codesourcery.com
Wed Aug 18 15:34:28 GMT 2021


Hi!

On 2021-08-18T09:35:25-0400, David Edelsohn <dje.gcc@gmail.com> wrote:
> This causes a bootstrap failure for me.
>
> PR/101959

Sorry for that; "details".  ;-|  OK to push the attached
"Make 'gcc/hash-map-tests.c:test_map_of_type_with_ctor_and_dtor_expand'
work on 32-bit architectures [PR101959]", which does resolve the issue
for a '-m32' i686-pc-linux-gnu build?


Grüße
 Thomas


> On Tue, Aug 17, 2021 at 5:00 AM Richard Biener via Gcc <gcc@gcc.gnu.org> wrote:
>>
>> On Tue, Aug 17, 2021 at 8:40 AM Thomas Schwinge <thomas@codesourcery.com> wrote:
>> >
>> > Hi!
>> >
>> > 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?)
>> >
>> > (Attached again, for easy reference.)
>> >
>> > > 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.
>>
>> > For 'selftest-c', we've got originally:
>> >
>> >     -fself-test: 74775 pass(es) in 0.309299 seconds
>> >     -fself-test: 74775 pass(es) in 0.366041 seconds
>> >     -fself-test: 74775 pass(es) in 0.356663 seconds
>> >     -fself-test: 74775 pass(es) in 0.355009 seconds
>> >     -fself-test: 74775 pass(es) in 0.367575 seconds
>> >     -fself-test: 74775 pass(es) in 0.320406 seconds
>> >
>> > ..., and with my changes we've got:
>> >
>> >     -fself-test: 94519 pass(es) in 0.327755 seconds
>> >     -fself-test: 94519 pass(es) in 0.369522 seconds
>> >     -fself-test: 94519 pass(es) in 0.355531 seconds
>> >     -fself-test: 94519 pass(es) in 0.362179 seconds
>> >     -fself-test: 94519 pass(es) in 0.363176 seconds
>> >     -fself-test: 94519 pass(es) in 0.318930 seconds
>> >
>> > So it really seems to be all in the noise?
>>
>> Yes.  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".
>>
>> Richard.
>>
>> > Yet:
>> >
>> > > Selftests run each time GCC
>> > > builds (i.e., even during day to day development).  It seems to me
>> > > that it might be better to run such selftests only as part of
>> > > the bootstrap process.
>> >
>> > I'd rather have thought about a '--param self-test-expensive' (or
>> > similar), and then invoke the selftests via a new
>> > 'gcc/testsuite/selftests/expensive.exp' (or similar).
>> >
>> > Or, adapt 'gcc/testsuite/gcc.dg/plugin/expensive_selftests_plugin.c',
>> > that is, invoke them via the GCC plugin mechanism, which also seems to be
>> > easy enough?
>> >
>> > I don't have a strong opinion about where/when these tests get run, so
>> > will happily take any suggestions.
>> >
>> >
>> > Grüße
>> >  Thomas
>> >
>> >
>> > -----------------
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-----------------
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