[PATCH] D50736: [libc++] Use correct rand.eng.mers all-zeroes seed sequence fallback

[Hubert Tong via Phabricator via cfe-commits]

hubert.reinterpretcast added a comment.

In https://reviews.llvm.org/D50736#1200774, @hubert.reinterpretcast wrote:

> In https://reviews.llvm.org/D50736#1200761, @mclow.lists wrote:
>
> > Is this test that's being added libc++ specific, or would it apply to other implementations as well?
>
>
> The test can apply to other implementations as well (although I am not sure how the `initializer_list` include behaves under C++03 on other implementations). Is there some other place to put such tests?


It seems that `test/std/numerics/rand/rand.eng/rand.eng.mers/` may be the place to add the test. I am looking into it.



================
Comment at: test/libcxx/numerics/rand/rand.eng.mers/cnstr_sseq_all_zero.pass.cpp:18
+
+// template <class Sseq> explicit mersenne_twister_engine(Sseq &q);
+
----------------
mclow.lists wrote:
> Please add a comment here about what's being tested, because when I look at this a year from now, I won't know what's going on.
> 
> Something like:
> `//  Finally, if the most significant w − r bits of X−n are zero, and if each of the other resulting Xi is 0, changes X−n to 2w−1.`
> 
I will add a comment to this effect. In an effort to be clear in the formatting, I will use the LaTeX snippet for the text.


Repository:
  rCXX libc++

https://reviews.llvm.org/D50736