[gcc r11-4716] libstdc++: Fix constant expressions in std::uniform_int_distribution

[Jonathan Wakely]

https://gcc.gnu.org/g:24366207b77481bceebb425569932297c441e04e

commit r11-4716-g24366207b77481bceebb425569932297c441e04e
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Nov 4 10:36:45 2020 +0000

    libstdc++: Fix constant expressions in std::uniform_int_distribution
    
    Clang and EDG say the class member access expressions __urng.min() and
    __urng.max() are not constant expressions, because the object expression
    __urng is not usable in a constant expresion. Use a qualified-id to call
    those static member functions instead.
    
    Co-authored-by: Stephan Bergmann <sbergman@redhat.com>
    
    libstdc++-v3/ChangeLog:
    
            * include/bits/uniform_int_dist.h (uniform_int_distribution::_S_nd):
            Use qualified-id to refer to static member functions.

Diff:
---
 libstdc++-v3/include/bits/uniform_int_dist.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/libstdc++-v3/include/bits/uniform_int_dist.h b/libstdc++-v3/include/bits/uniform_int_dist.h
index 524593bb984..8f02b85c9bb 100644
--- a/libstdc++-v3/include/bits/uniform_int_dist.h
+++ b/libstdc++-v3/include/bits/uniform_int_dist.h
@@ -278,12 +278,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	typedef typename make_unsigned<result_type>::type __utype;
 	typedef typename common_type<_Gresult_type, __utype>::type __uctype;
 
-	static_assert( __urng.min() < __urng.max(),
+	constexpr __uctype __urngmin = _UniformRandomBitGenerator::min();
+	constexpr __uctype __urngmax = _UniformRandomBitGenerator::max();
+	static_assert( __urngmin < __urngmax,
 	    "Uniform random bit generator must define min() < max()");
-
-	constexpr __uctype __urngmin = __urng.min();
-	constexpr __uctype __urngmax = __urng.max();
 	constexpr __uctype __urngrange = __urngmax - __urngmin;
+
 	const __uctype __urange
 	  = __uctype(__param.b()) - __uctype(__param.a());