re PR c++/10611 (operations on vector mode not recognized in C++)

        PR c++/10611
        * cvt.c (build_expr_type_conversion): Same.
        * typeck.c (build_binary_op): Handle vectors.
        (common_type): Same.
        (type_after_usual_arithmetic_conversions): Same.
        * testsuite/g++.dg/conversion/simd2.C: New.

From-SVN: r100823