[PATCH v2][Aarch64] Add vectorized mersenne twister

[Michael Collison]

I took his "okay" as an approval since he is listed as a maintainer.

-----Original Message-----
From: Jonathan Wakely [mailto:jwakely@redhat.com] 
Sent: Tuesday, July 25, 2017 10:37 AM
To: Michael Collison <Michael.Collison@arm.com>
Cc: gcc-patches@gcc.gnu.org; libstdc++@gcc.gnu.org; nd <nd@arm.com>
Subject: Re: [PATCH v2][Aarch64] Add vectorized mersenne twister

On 25/07/17 18:33 +0100, Jonathan Wakely wrote:
>On 25/07/17 18:31 +0100, Jonathan Wakely wrote:
>>On 18/07/17 05:53 +0000, Michael Collison wrote:
>>>This is the second version of a patch for Aarc64 to add a vectorized mersenne twister to libstdc++. The first version used intrinsics and included "arm_neon.h". After feedback from the community this version uses only GCC vector extensions and Aarch64 simd data types.
>>>
>>>This patch adds an vectorized implementation of the mersenne twister random number generator. This implementation is approximately 2.6 times faster than the non-vectorized implementation.
>>>
>>>Sample code to use the new generator would look like this:
>>>
>>>#include <random>
>>>#include <ext/random>
>>>#include <iostream>
>>>
>>>int
>>>main()
>>>{
>>>__gnu_cxx::sfmt19937 mt(1729);
>>>
>>>std::uniform_int_distribution<int> dist(0,1008);
>>>
>>>for (int i = 0; i < 16; ++i)
>>>  {
>>>    std::cout << dist(mt) << " ";
>>>  }
>>>}
>>>
>>>Okay for trunk?
>>>
>>>2017-07-16  Michael Collison  <michael.collison@arm.com>
>>>
>>>	Add optimized implementation of mersenne twister for aarch64
>>>	* config/cpu/aarch64/opt/ext/opt_random.h: New file.
>>>	(__arch64_recursion): New function.
>>>	(__aarch64_lsr_128): New function.
>>>	(__aarch64_lsl_128): New function.
>>>	(operator==): New function.
>>>	(simd_fast_mersenne_twister_engine): Implement
>>>	method _M_gen_rand.
>>>	* config/cpu/aarch64/opt/bits/opt_random.h: New file.
>>>	* include/ext/random: (simd_fast_mersenne_twister_engine):
>>>	add _M_state private array.
>>>
>>
>>This has been committed, was it actually approved?
>>
>
>It looks OK anyway, apart from the doxygen comment on ext/opt_random.h 
>which names the wrong file: @file ext/random.tcc
>
>

Oh, it looks like this mail was sent to "gcc--patches@gcc.gnu.org" and then another copy was sent to gcc-patches, but without CCing the
libstdc++ list.

I'm not sure if Ulrich's "looks OK" was an explicit approval, but he is a libstdc++ maintainer so let's say yes :)

https://gcc.gnu.org/ml/gcc-patches/2017-07/msg01017.html