[Bug c++/69884] New: [6 Regression] warning: ignoring attributes on template argument

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69884

            Bug ID: 69884
           Summary: [6 Regression] warning: ignoring attributes on
                    template argument
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: trippels at gcc dot gnu.org
  Target Milestone: ---

Running the Eigen testsuite shows many instances of:

markus@x4 build % cat sparse_product.ii
typedef float __m128 __attribute__((__vector_size__(16), __may_alias__));
template <typename> struct A;
template <> struct A<__m128>;

markus@x4 build % clang++ -Wall -Wextra -O2 -c sparse_product.ii
markus@x4 build % icpc -Wall -Wextra -O2 -c sparse_product.ii
markus@x4 build % /usr/x86_64-pc-linux-gnu/gcc-bin/4.9.3/g++ -Wall -Wextra -O2
-c sparse_product.ii
markus@x4 build % /usr/x86_64-pc-linux-gnu/gcc-bin/5.3.1/g++ -Wall -Wextra -O2
-c sparse_product.ii
markus@x4 build % g++ -O2 -c sparse_product.ii
sparse_product.ii:3:28: warning: ignoring attributes on template argument
‘__m128 {aka __vector(4) float}’
 template <> struct A<__m128>;
                            ^