diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorFFT.h b/unsupported/Eigen/CXX11/src/Tensor/TensorFFT.h
index 867512d675..ece2695eef 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorFFT.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorFFT.h
@@ -225,8 +225,9 @@ struct TensorEvaluator<const TensorFFTOp<FFT, ArgType, FFTResultType, FFTDir>, D
         // For n > 2 we use the recurrence t_n = t_{n-1}^2 / t_{n-2} * t_1^2
         pos_j_base_powered[0] = ComplexScalar(1, 0);
         if (line_len > 1) {
+          const RealScalar PI(3.14159265358979323846);
           const ComplexScalar pos_j_base = ComplexScalar(
-              std::cos(M_PI / line_len), std::sin(M_PI / line_len));
+              std::cos(PI / line_len), std::sin(PI / line_len));
           pos_j_base_powered[1] = pos_j_base;
           if (line_len > 2) {
             const ComplexScalar pos_j_base_sq = pos_j_base * pos_j_base;