C++ PATCH for c++/92062 - ODR-use ignored for static member of class template

[Marek Polacek]

has_value_dependent_address wasn't stripping location wrappers so it
gave the wrong answer for "&x" in the static_assert.  That led us to
thinking that the expression isn't instantiation-dependent, and we
skipped static initialization of A<0>::x.

This patch adds stripping so that has_value_dependent_address gives the
same answer as it used to before the location wrappers addition.

Bootstrapped/regtested on x86_64-linux, ok for trunk and 9?

2019-10-11  Marek Polacek  <pola...@redhat.com>

        PR c++/92062 - ODR-use ignored for static member of class template.
        * pt.c (has_value_dependent_address): Strip location wrappers.

        * g++.dg/cpp0x/constexpr-odr1.C: New test.
        * g++.dg/cpp0x/constexpr-odr2.C: New test.

diff --git gcc/cp/pt.c gcc/cp/pt.c
index 84464436991..521d0c56002 100644
--- gcc/cp/pt.c
+++ gcc/cp/pt.c
@@ -6542,6 +6542,8 @@ check_valid_ptrmem_cst_expr (tree type, tree expr,
 static bool
 has_value_dependent_address (tree op)
 {
+  STRIP_ANY_LOCATION_WRAPPER (op);
+
   /* We could use get_inner_reference here, but there's no need;
      this is only relevant for template non-type arguments, which
      can only be expressed as &id-expression.  */
diff --git gcc/testsuite/g++.dg/cpp0x/constexpr-odr1.C 
gcc/testsuite/g++.dg/cpp0x/constexpr-odr1.C
new file mode 100644
index 00000000000..cf3f95f0565
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp0x/constexpr-odr1.C
@@ -0,0 +1,19 @@
+// PR c++/92062 - ODR-use ignored for static member of class template.
+// { dg-do run { target c++11 } }
+
+template<int> struct A {
+  static const bool x;
+  static_assert(&x, ""); // odr-uses A<...>::x
+};
+
+int g;
+
+template<int I>
+const bool A<I>::x = (g = 42, false);
+
+void f(A<0>) {}        // A<0> must be complete, so is instantiated
+int main()
+{
+  if (g != 42)
+    __builtin_abort ();
+}
diff --git gcc/testsuite/g++.dg/cpp0x/constexpr-odr2.C 
gcc/testsuite/g++.dg/cpp0x/constexpr-odr2.C
new file mode 100644
index 00000000000..0927488e569
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp0x/constexpr-odr2.C
@@ -0,0 +1,19 @@
+// PR c++/92062 - ODR-use ignored for static member of class template.
+// { dg-do run { target c++11 } }
+
+template<int> struct A {
+  static const bool x;
+  enum { force_instantiation =! &x}; // odr-uses A<...>::x
+};
+
+int g;
+
+template<int I>
+const bool A<I>::x = (g = 42, false);
+
+void f(A<0>) {}        // A<0> must be complete, so is instantiated
+int main()
+{
+  if (g != 42)
+    __builtin_abort ();
+}