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

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  <polacek@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.

Ping.

On Fri, Oct 11, 2019 at 04:23:34PM -0400, Marek Polacek wrote:
> 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  <polacek@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 ();
> +}

Marek

On 10/11/19 4:23 PM, Marek Polacek wrote:
> 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  <polacek@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 ();
> +}
> 

OK.

Jason