[gcc r12-2359] libstdc++: Modernize <bits/random.h> helpers

[gcc r12-2359] libstdc++: Modernize <bits/random.h> helpers

[Jonathan Wakely]

https://gcc.gnu.org/g:95891ca020591196cde50c4cde4cab14783a3c00

commit r12-2359-g95891ca020591196cde50c4cde4cab14783a3c00
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Jul 16 13:39:25 2021 +0100

    libstdc++: Modernize <bits/random.h> helpers
    
    Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
    
    libstdc++-v3/ChangeLog:
    
            * include/bits/random.h (_Shift::__value): Use constexpr.
            (_Select_uint_least_t::type): Use using-declaration.
            (_Mod): Likewise.
            * testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error
            line number.

Diff:
---
 libstdc++-v3/include/bits/random.h                  | 21 ++++++++++++---------
 .../testsuite/26_numerics/random/pr60037-neg.cc     |  2 +-
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/libstdc++-v3/include/bits/random.h b/libstdc++-v3/include/bits/random.h
index 6d0e1544c90..c5cae87b636 100644
--- a/libstdc++-v3/include/bits/random.h
+++ b/libstdc++-v3/include/bits/random.h
@@ -68,11 +68,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	     bool = __w < static_cast<size_t>
 			  (std::numeric_limits<_UIntType>::digits)>
       struct _Shift
-      { static const _UIntType __value = 0; };
+      { static constexpr _UIntType __value = 0; };
 
     template<typename _UIntType, size_t __w>
       struct _Shift<_UIntType, __w, true>
-      { static const _UIntType __value = _UIntType(1) << __w; };
+      { static constexpr _UIntType __value = _UIntType(1) << __w; };
 
     template<int __s,
 	     int __which = ((__s <= __CHAR_BIT__ * sizeof (int))
@@ -88,20 +88,20 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
     template<int __s>
       struct _Select_uint_least_t<__s, 4>
-      { typedef unsigned int type; };
+      { using type = unsigned int; };
 
     template<int __s>
       struct _Select_uint_least_t<__s, 3>
-      { typedef unsigned long type; };
+      { using type = unsigned long; };
 
     template<int __s>
       struct _Select_uint_least_t<__s, 2>
-      { typedef unsigned long long type; };
+      { using type = unsigned long long; };
 
 #if __SIZEOF_INT128__ > __SIZEOF_LONG_LONG__
     template<int __s>
       struct _Select_uint_least_t<__s, 1>
-      { __extension__ typedef unsigned __int128 type; };
+      { __extension__ using type = unsigned __int128; };
 #endif
 
     // Assume a != 0, a < m, c < m, x < m.
@@ -111,11 +111,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
              bool __schrage_ok = __m % __a < __m / __a>
       struct _Mod
       {
-	typedef typename _Select_uint_least_t<std::__lg(__a)
-					      + std::__lg(__m) + 2>::type _Tp2;
 	static _Tp
 	__calc(_Tp __x)
-	{ return static_cast<_Tp>((_Tp2(__a) * __x + __c) % __m); }
+	{
+	  using _Tp2
+	    = typename _Select_uint_least_t<std::__lg(__a)
+					    + std::__lg(__m) + 2>::type;
+	  return static_cast<_Tp>((_Tp2(__a) * __x + __c) % __m);
+	}
       };
 
     // Schrage.
diff --git a/libstdc++-v3/testsuite/26_numerics/random/pr60037-neg.cc b/libstdc++-v3/testsuite/26_numerics/random/pr60037-neg.cc
index 3ded306bd5f..d6e6399bd79 100644
--- a/libstdc++-v3/testsuite/26_numerics/random/pr60037-neg.cc
+++ b/libstdc++-v3/testsuite/26_numerics/random/pr60037-neg.cc
@@ -10,6 +10,6 @@ std::__detail::_Adaptor<std::mt19937, unsigned long> aurng(urng);
 auto x = std::generate_canonical<std::size_t,
 			std::numeric_limits<std::size_t>::digits>(urng);
 
-// { dg-error "static assertion failed: template argument must be a floating point type" "" { target *-*-* } 166 }
+// { dg-error "static assertion failed: template argument must be a floating point type" "" { target *-*-* } 169 }
 
 // { dg-error "static assertion failed: template argument must be a floating point type" "" { target *-*-* } 3350 }