[gcc r13-164] libstdc++: Simplify std::normal_distribution equality operator

[gcc r13-164] libstdc++: Simplify std::normal_distribution equality operator

[Jonathan Wakely]

https://gcc.gnu.org/g:42991a911685a419794c47eba640d35ca60c2d99

commit r13-164-g42991a911685a419794c47eba640d35ca60c2d99
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri May 6 21:37:47 2022 +0100

    libstdc++: Simplify std::normal_distribution equality operator
    
    libstdc++-v3/ChangeLog:
    
            * include/bits/random.tcc (operator==): Only check
            normal_distribution::_M_saved_available once.
            * testsuite/26_numerics/random/normal_distribution/operators/equal.cc:
            Check equality after state changes.
            * testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error
            lineno.

Diff:
---
 libstdc++-v3/include/bits/random.tcc                 | 10 +---------
 .../random/normal_distribution/operators/equal.cc    | 20 ++++++++++++++++++++
 .../testsuite/26_numerics/random/pr60037-neg.cc      |  2 +-
 3 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/libstdc++-v3/include/bits/random.tcc b/libstdc++-v3/include/bits/random.tcc
index 87a16a21336..cb1d3675783 100644
--- a/libstdc++-v3/include/bits/random.tcc
+++ b/libstdc++-v3/include/bits/random.tcc
@@ -1907,15 +1907,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     {
       if (__d1._M_param == __d2._M_param
 	  && __d1._M_saved_available == __d2._M_saved_available)
-	{
-	  if (__d1._M_saved_available
-	      && __d1._M_saved == __d2._M_saved)
-	    return true;
-	  else if(!__d1._M_saved_available)
-	    return true;
-	  else
-	    return false;
-	}
+	return __d1._M_saved_available ? __d1._M_saved == __d2._M_saved : true;
       else
 	return false;
     }
diff --git a/libstdc++-v3/testsuite/26_numerics/random/normal_distribution/operators/equal.cc b/libstdc++-v3/testsuite/26_numerics/random/normal_distribution/operators/equal.cc
index a3435232961..81534e95797 100644
--- a/libstdc++-v3/testsuite/26_numerics/random/normal_distribution/operators/equal.cc
+++ b/libstdc++-v3/testsuite/26_numerics/random/normal_distribution/operators/equal.cc
@@ -34,8 +34,28 @@ test01()
   VERIFY( !(u == v) );
 }
 
+void
+test02()
+{
+  std::normal_distribution<double> u(5.0, 2.0), v(u);
+  VERIFY( u == v );
+  u.reset();
+  VERIFY( u == v );
+
+  std::minstd_rand0 g1, g2;
+  (void) u(g1); // u._M_saved_available = true
+  VERIFY( !(u == v) );
+  (void) v(g2); // v._M_saved_available = true
+  VERIFY( u == v );
+  u.reset();    // u._M_saved_available = false
+  VERIFY( !(u == v) );
+  v.reset();    // v._M_saved_available = false
+  VERIFY( u == v );
+}
+
 int main()
 {
   test01();
+  test02();
   return 0;
 }
diff --git a/libstdc++-v3/testsuite/26_numerics/random/pr60037-neg.cc b/libstdc++-v3/testsuite/26_numerics/random/pr60037-neg.cc
index 3ab9c44232e..c58f480640f 100644
--- a/libstdc++-v3/testsuite/26_numerics/random/pr60037-neg.cc
+++ b/libstdc++-v3/testsuite/26_numerics/random/pr60037-neg.cc
@@ -12,4 +12,4 @@ auto x = std::generate_canonical<std::size_t,
 
 // { 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 *-*-* } 3356 }
+// { dg-error "static assertion failed: template argument must be a floating point type" "" { target *-*-* } 3348 }