[PATCH] Add experimental::sample and experimental::shuffle from N4531

[Jonathan Wakely]

On 29/06/18 09:39 +0200, Christophe Lyon wrote:
>On Fri, 29 Jun 2018 at 09:21, Jonathan Wakely <jwakely@redhat.com> wrote:
>>
>> On 29/06/18 08:55 +0200, Christophe Lyon wrote:
>> >On Mon, 25 Jun 2018 at 18:23, Jonathan Wakely <jwakely@redhat.com> wrote:
>> >>
>> >> The additions to <experimental/random> were added in 2015 but the new
>> >> algorithms in <experimental/algorithm> were not. This adds them.
>> >>
>> >>         * include/experimental/algorithm (sample, shuffle): Add new overloads
>> >>         using per-thread random number engine.
>> >>         * testsuite/experimental/algorithm/sample.cc: Simpify and reduce
>> >>         dependencies by using __gnu_test::test_container.
>> >>         * testsuite/experimental/algorithm/sample-2.cc: New.
>> >>         * testsuite/experimental/algorithm/shuffle.cc: New.
>> >>
>> >> Tested x86_64-linux, committed to trunk.
>> >>
>> >> This would be safe to backport, but nobody has noticed the algos are
>> >> missing or complained, so it doesn't seem very important to backport.
>> >>
>> >>
>> >
>> >Hi,
>> >
>> >On bare-metal targets (aarch64 and arm + newlib), I've noticed that
>> >the two new tests fail:
>> >PASS: experimental/algorithm/shuffle.cc (test for excess errors)
>> >spawn /aci-gcc-fsf/builds/gcc-fsf-gccsrc/obj-arm-none-eabi/gcc3/utils/bin/qemu-wrapper.sh
>> >./shuffle.exe
>> >terminate called after throwing an instance of 'std::runtime_error'
>> >  what():  random_device::random_device(const std::string&)
>> >
>> >*** EXIT code 4242
>> >FAIL: experimental/algorithm/shuffle.cc execution test
>> >
>> >PASS: experimental/algorithm/sample-2.cc (test for excess errors)
>> >spawn /aci-gcc-fsf/builds/gcc-fsf-gccsrc/obj-arm-none-eabi/gcc3/utils/bin/qemu-wrapper.sh
>> >./sample-2.exe
>> >terminate called after throwing an instance of 'std::runtime_error'
>> >  what():  random_device::random_device(const std::string&)
>> >
>> >*** EXIT code 4242
>> >FAIL: experimental/algorithm/sample-2.cc execution test
>> >
>> >Does this ring a bell?
>>
>> Does the existing testsuite/experimental/random/randint.cc file fail
>> in the same way?
>>
>
>Yes it does.
>
>And so do:
>25_algorithms/make_heap/complexity.cc

This one also uses std::random_device.

>23_containers/array/element_access/at_neg.cc

Hmm,

  // Expected behavior is to either throw and have the uncaught
  // exception end up in a terminate handler which eventually exits,
  // or abort. (Depending on -fno-exceptions.)

So this is expected to XFAIL.

>26_numerics/random/random_device/cons/default.cc

We should XFAIL the ones that use std::random_device, if we can
identify an effective target to describe them.