C++20 allows floating-point types for non-type template parameters;
floating-point values are considered to be equivalent template arguments if
they are "identical", which conveniently seems to map onto an existing GCC
predicate.
gcc/cp/ChangeLog:
* tree.c (cp_tree_equal): Use real_identical.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/nontype-float1.C: New test.
return tree_int_cst_equal (t1, t2);
case REAL_CST:
- return real_equal (&TREE_REAL_CST (t1), &TREE_REAL_CST (t2));
+ return real_identical (&TREE_REAL_CST (t1), &TREE_REAL_CST (t2));
case STRING_CST:
return TREE_STRING_LENGTH (t1) == TREE_STRING_LENGTH (t2)
--- /dev/null
+// { dg-do compile { target c++20 } }
+
+#include <cmath>
+
+template<auto> class MyClass { };
+
+static_assert(__is_same(MyClass<NAN>, MyClass<NAN>));
+
+constexpr auto mynan = NAN;
+static_assert(__is_same(MyClass<mynan>, MyClass<mynan>));
+
+static_assert(__is_same(MyClass<NAN>, MyClass<mynan>));