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/* { dg-do compile } */

#include <altivec.h>

inline void

transpose4x4(vector float *matrix)

{

  vector float v0, v1, v2, v3;

  v0 = vec_mergeh(matrix[0], matrix[2]);

  v1 = vec_mergel(matrix[0], matrix[2]);

  v2 = vec_mergeh(matrix[1], matrix[3]);

  v3 = vec_mergel(matrix[1], matrix[3]);

  matrix[0] = vec_mergeh(v0, v2);

  matrix[1] = vec_mergel(v0, v2);

  matrix[2] = vec_mergeh(v1, v3);

  matrix[3] = vec_mergel(v1, v3);

}

void

vec_ifft64(vector float *x0, vector float *x1)

{

  int i;

  vector float real[4], imag[4];

  vector float c0r, c1r, c2r, c3r, c0i, c1i, c2i, c3i;

  vector float d0r, d1r, d2r, d3r, d0i, d1i, d2i, d3i;

  /*

   *  N=64

   *

   *  Stage 1: t=1 => k = 0, j = 0..15

   *  ================================

   *  for j = 0:15

   *    c0 = x0(j+0*16);

   *    c1 = x0(j+1*16);

   *    c2 = x0(j+2*16);

   *    c3 = x0(j+3*16);

   *

   *    d0 = c0 + c2;

   *    d1 = c0 - c2;

   *    d2 = c1 + c3;

   *    d3 = i*(c1 - c3);

   *

   *    x1(4j+0) = d0 + d2;

   *    x1(4j+1) = d1 + d3;

   *    x1(4j+2) = d0 - d2;

   *    x1(4j+3) = d1 - d3;

   *  end

   ******************************************************/

  for (i=0; i < 4; i++)

    {

      c0r = x0[i];

      c1r = x0[i+4];

      c2r = x0[i+8];

      c3r = x0[i+12];

      c0i = x0[i+16];

      c1i = x0[i+20];

      c2i = x0[i+24];

      c3i = x0[i+28];

      d0r = vec_add(c0r, c2r);

      d1r = vec_sub(c0r, c2r);

      d2r = vec_add(c1r, c3r);

      d3r = vec_sub(c3i, c1i);

      d0i = vec_add(c0i, c2i);

      d1i = vec_sub(c0i, c2i);

      d2i = vec_add(c1i, c3i);

      d3i = vec_sub(c1r, c3r);

      /* Calculate real{x1} */

      real[0] = vec_add(d0r, d2r);

      real[1] = vec_add(d1r, d3r);

      real[2] = vec_sub(d0r, d2r);

      real[3] = vec_sub(d1r, d3r);

      transpose4x4(real);

      /* Calculate imag{x1} */

      imag[0] = vec_add(d0i, d2i);

      imag[1] = vec_add(d1i, d3i);

      imag[2] = vec_sub(d0i, d2i);

      imag[3] = vec_sub(d1i, d3i);

      transpose4x4(imag);

      x1[4*i]   = real[0];

      x1[4*i+1] = real[1];

      x1[4*i+2] = real[2];

      x1[4*i+3] = real[3];

      x1[4*i+16] = imag[0];

      x1[4*i+17] = imag[1];

      x1[4*i+18] = imag[2];

      x1[4*i+19] = imag[3];

    }

}