int dfft(double x[], double y[], int np) {
  double *px, *py;
  int i, j, k, m, n, i0, i1, i2, i3, is, id, n1, n2, n4;
  double a, e, a3, cc1, ss1, cc3, ss3, r1, r2, s1, s2, s3, xt, tpi;
  px = x - 1;
  py = y - 1;
  i = 2;
  m = 1;
  while (i < np) {
    i = i + i;
    m = m + 1;
  }
  n = i;
  if (n != np) {
    for (i = np + 1; i <= n; i++) {
      px[i] = 0.0;
      py[i] = 0.0;
    }
    printf("\nuse %d point fft", n);
  }
  n2 = n + n;
  tpi = 2.0 * 3.14159265358979323846;
  for (k = 1; k <= m - 1; k++) {
    n2 = n2 / 2;
    n4 = n2 / 4;
    e = tpi / (double)n2;
    a = 0.0;
    for (j = 1; j <= n4; j++) {
      a3 = 3.0 * a;
      cc1 = cos(a);
      ss1 = sin(a);
      cc3 = cos(a3);
      ss3 = sin(a3);
      a = e * (double)j;
      is = j;
      id = 2 * n2;
      while (is < n) {
        for (i0 = is; i0 <= n - 1; i0 = i0 + id) {
          i1 = i0 + n4;
          i2 = i1 + n4;
          i3 = i2 + n4;
          r1 = px[i0] - px[i2];
          px[i0] = px[i0] + px[i2];
          r2 = px[i1] - px[i3];
          px[i1] = px[i1] + px[i3];
          s1 = py[i0] - py[i2];
          py[i0] = py[i0] + py[i2];
          s2 = py[i1] - py[i3];
          py[i1] = py[i1] + py[i3];
          s3 = r1 - s2;
          r1 = r1 + s2;
          s2 = r2 - s1;
          r2 = r2 + s1;
          px[i2] = r1 * cc1 - s2 * ss1;
          py[i2] = -s2 * cc1 - r1 * ss1;
          px[i3] = s3 * cc3 + r2 * ss3;
          py[i3] = r2 * cc3 - s3 * ss3;
        }
        is = 2 * id - n2 + j;
        id = 4 * id;
      }
    }
  }
  is = 1;
  id = 4;
  while (is < n) {
    for (i0 = is; i0 <= n; i0 = i0 + id) {
      i1 = i0 + 1;
      r1 = px[i0];
      px[i0] = r1 + px[i1];
      px[i1] = r1 - px[i1];
      r1 = py[i0];
      py[i0] = r1 + py[i1];
      py[i1] = r1 - py[i1];
    }
    is = 2 * id - 1;
    id = 4 * id;
  }
  j = 1;
  n1 = n - 1;
  for (i = 1; i <= n1; i++) {
    if (i < j) {
      xt = px[j];
      px[j] = px[i];
      px[i] = xt;
      xt = py[j];
      py[j] = py[i];
      py[i] = xt;
    }
    k = n / 2;
    while (k < j) {
      j = j - k;
      k = k / 2;
    }
    j = j + k;
  }
  return (n);
}


x86 assembly (clang, -O0):
<dfft>:
push   %rbp
mov    %rsp,%rbp
sub    $0xd0,%rsp
mov    %rdi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
mov    %edx,-0x14(%rbp)
mov    -0x8(%rbp),%rax
add    $0xfffffffffffffff8,%rax
mov    %rax,-0x20(%rbp)
mov    -0x10(%rbp),%rax
add    $0xfffffffffffffff8,%rax
mov    %rax,-0x28(%rbp)
movl   $0x2,-0x2c(%rbp)
movl   $0x1,-0x38(%rbp)
mov    -0x2c(%rbp),%eax
cmp    -0x14(%rbp),%eax
jge    118f <dfft+0x5f>
mov    -0x2c(%rbp),%eax
add    -0x2c(%rbp),%eax
mov    %eax,-0x2c(%rbp)
mov    -0x38(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x38(%rbp)
jmp    116c <dfft+0x3c>
mov    -0x2c(%rbp),%eax
mov    %eax,-0x3c(%rbp)
mov    -0x3c(%rbp),%eax
cmp    -0x14(%rbp),%eax
je     11f5 <dfft+0xc5>
mov    -0x14(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x2c(%rbp)
mov    -0x2c(%rbp),%eax
cmp    -0x3c(%rbp),%eax
jg     11e4 <dfft+0xb4>
mov    -0x20(%rbp),%rax
movslq -0x2c(%rbp),%rcx
xorps  %xmm0,%xmm0
movsd  %xmm0,(%rax,%rcx,8)
mov    -0x28(%rbp),%rax
movslq -0x2c(%rbp),%rcx
xorps  %xmm0,%xmm0
movsd  %xmm0,(%rax,%rcx,8)
mov    -0x2c(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x2c(%rbp)
jmp    11aa <dfft+0x7a>
mov    -0x3c(%rbp),%esi
lea    0xe22(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
mov    -0x3c(%rbp),%eax
add    -0x3c(%rbp),%eax
mov    %eax,-0x5c(%rbp)
movsd  0xdfa(%rip),%xmm0
movsd  %xmm0,-0xd0(%rbp)
ff
movl   $0x1,-0x34(%rbp)
mov    -0x34(%rbp),%eax
mov    -0x38(%rbp),%ecx
sub    $0x1,%ecx
cmp    %ecx,%eax
jg     1629 <dfft+0x4f9>
mov    -0x5c(%rbp),%eax
mov    $0x2,%ecx
cltd
idiv   %ecx
mov    %eax,-0x5c(%rbp)
mov    -0x5c(%rbp),%eax
mov    $0x4,%ecx
cltd
idiv   %ecx
mov    %eax,-0x60(%rbp)
movsd  -0xd0(%rbp),%xmm0
ff
cvtsi2sdl -0x5c(%rbp),%xmm1
divsd  %xmm1,%xmm0
movsd  %xmm0,-0x70(%rbp)
xorps  %xmm0,%xmm0
movsd  %xmm0,-0x68(%rbp)
movl   $0x1,-0x30(%rbp)
mov    -0x30(%rbp),%eax
cmp    -0x60(%rbp),%eax
jg     1616 <dfft+0x4e6>
movsd  0xd8d(%rip),%xmm0
mulsd  -0x68(%rbp),%xmm0
movsd  %xmm0,-0x78(%rbp)
movsd  -0x68(%rbp),%xmm0
call   1050 <cos@plt>
movsd  %xmm0,-0x80(%rbp)
movsd  -0x68(%rbp),%xmm0
call   1040 <sin@plt>
movsd  %xmm0,-0x88(%rbp)
ff
movsd  -0x78(%rbp),%xmm0
call   1050 <cos@plt>
movsd  %xmm0,-0x90(%rbp)
ff
movsd  -0x78(%rbp),%xmm0
call   1040 <sin@plt>
movsd  %xmm0,-0x98(%rbp)
ff
movsd  -0x70(%rbp),%xmm0
cvtsi2sdl -0x30(%rbp),%xmm1
mulsd  %xmm1,%xmm0
movsd  %xmm0,-0x68(%rbp)
mov    -0x30(%rbp),%eax
mov    %eax,-0x50(%rbp)
mov    -0x5c(%rbp),%eax
shl    $0x1,%eax
mov    %eax,-0x54(%rbp)
mov    -0x50(%rbp),%eax
cmp    -0x3c(%rbp),%eax
jge    1603 <dfft+0x4d3>
mov    -0x50(%rbp),%eax
mov    %eax,-0x40(%rbp)
mov    -0x40(%rbp),%eax
mov    -0x3c(%rbp),%ecx
sub    $0x1,%ecx
cmp    %ecx,%eax
jg     15e6 <dfft+0x4b6>
mov    -0x40(%rbp),%eax
add    -0x60(%rbp),%eax
mov    %eax,-0x44(%rbp)
mov    -0x44(%rbp),%eax
add    -0x60(%rbp),%eax
mov    %eax,-0x48(%rbp)
mov    -0x48(%rbp),%eax
add    -0x60(%rbp),%eax
mov    %eax,-0x4c(%rbp)
mov    -0x20(%rbp),%rax
movslq -0x40(%rbp),%rcx
movsd  (%rax,%rcx,8),%xmm0
mov    -0x20(%rbp),%rax
movslq -0x48(%rbp),%rcx
subsd  (%rax,%rcx,8),%xmm0
movsd  %xmm0,-0xa0(%rbp)
ff
mov    -0x20(%rbp),%rax
movslq -0x40(%rbp),%rcx
movsd  (%rax,%rcx,8),%xmm0
mov    -0x20(%rbp),%rax
movslq -0x48(%rbp),%rcx
addsd  (%rax,%rcx,8),%xmm0
mov    -0x20(%rbp),%rax
movslq -0x40(%rbp),%rcx
movsd  %xmm0,(%rax,%rcx,8)
mov    -0x20(%rbp),%rax
movslq -0x44(%rbp),%rcx
movsd  (%rax,%rcx,8),%xmm0
mov    -0x20(%rbp),%rax
movslq -0x4c(%rbp),%rcx
subsd  (%rax,%rcx,8),%xmm0
movsd  %xmm0,-0xa8(%rbp)
ff
mov    -0x20(%rbp),%rax
movslq -0x44(%rbp),%rcx
movsd  (%rax,%rcx,8),%xmm0
mov    -0x20(%rbp),%rax
movslq -0x4c(%rbp),%rcx
addsd  (%rax,%rcx,8),%xmm0
mov    -0x20(%rbp),%rax
movslq -0x44(%rbp),%rcx
movsd  %xmm0,(%rax,%rcx,8)
mov    -0x28(%rbp),%rax
movslq -0x40(%rbp),%rcx
movsd  (%rax,%rcx,8),%xmm0
mov    -0x28(%rbp),%rax
movslq -0x48(%rbp),%rcx
subsd  (%rax,%rcx,8),%xmm0
movsd  %xmm0,-0xb0(%rbp)
ff
mov    -0x28(%rbp),%rax
movslq -0x40(%rbp),%rcx
movsd  (%rax,%rcx,8),%xmm0
mov    -0x28(%rbp),%rax
movslq -0x48(%rbp),%rcx
addsd  (%rax,%rcx,8),%xmm0
mov    -0x28(%rbp),%rax
movslq -0x40(%rbp),%rcx
movsd  %xmm0,(%rax,%rcx,8)
mov    -0x28(%rbp),%rax
movslq -0x44(%rbp),%rcx
movsd  (%rax,%rcx,8),%xmm0
mov    -0x28(%rbp),%rax
movslq -0x4c(%rbp),%rcx
subsd  (%rax,%rcx,8),%xmm0
movsd  %xmm0,-0xb8(%rbp)
ff
mov    -0x28(%rbp),%rax
movslq -0x44(%rbp),%rcx
movsd  (%rax,%rcx,8),%xmm0
mov    -0x28(%rbp),%rax
movslq -0x4c(%rbp),%rcx
addsd  (%rax,%rcx,8),%xmm0
mov    -0x28(%rbp),%rax
movslq -0x44(%rbp),%rcx
movsd  %xmm0,(%rax,%rcx,8)
movsd  -0xa0(%rbp),%xmm0
ff
subsd  -0xb8(%rbp),%xmm0
ff
movsd  %xmm0,-0xc0(%rbp)
ff
movsd  -0xa0(%rbp),%xmm0
ff
addsd  -0xb8(%rbp),%xmm0
ff
movsd  %xmm0,-0xa0(%rbp)
ff
movsd  -0xa8(%rbp),%xmm0
ff
subsd  -0xb0(%rbp),%xmm0
ff
movsd  %xmm0,-0xb8(%rbp)
ff
movsd  -0xa8(%rbp),%xmm0
ff
addsd  -0xb0(%rbp),%xmm0
ff
movsd  %xmm0,-0xa8(%rbp)
ff
movsd  -0xa0(%rbp),%xmm0
ff
movsd  -0x80(%rbp),%xmm2
movsd  -0xb8(%rbp),%xmm1
ff
mulsd  -0x88(%rbp),%xmm1
ff
movq   %xmm1,%rax
movabs $0x8000000000000000,%rcx
xor    %rcx,%rax
movq   %rax,%xmm1
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
mov    -0x20(%rbp),%rax
movslq -0x48(%rbp),%rcx
movsd  %xmm0,(%rax,%rcx,8)
movsd  -0xb8(%rbp),%xmm0
ff
movq   %xmm0,%rax
movabs $0x8000000000000000,%rcx
xor    %rcx,%rax
movq   %rax,%xmm0
movsd  -0x80(%rbp),%xmm2
movsd  -0xa0(%rbp),%xmm1
ff
mulsd  -0x88(%rbp),%xmm1
ff
movq   %xmm1,%rax
movabs $0x8000000000000000,%rcx
xor    %rcx,%rax
movq   %rax,%xmm1
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
mov    -0x28(%rbp),%rax
movslq -0x48(%rbp),%rcx
movsd  %xmm0,(%rax,%rcx,8)
movsd  -0xc0(%rbp),%xmm0
ff
movsd  -0x90(%rbp),%xmm2
ff
movsd  -0xa8(%rbp),%xmm1
ff
mulsd  -0x98(%rbp),%xmm1
ff
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
mov    -0x20(%rbp),%rax
movslq -0x4c(%rbp),%rcx
movsd  %xmm0,(%rax,%rcx,8)
movsd  -0xa8(%rbp),%xmm0
ff
movsd  -0x90(%rbp),%xmm2
ff
movsd  -0xc0(%rbp),%xmm1
ff
mulsd  -0x98(%rbp),%xmm1
ff
movq   %xmm1,%rax
movabs $0x8000000000000000,%rcx
xor    %rcx,%rax
movq   %rax,%xmm1
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
mov    -0x28(%rbp),%rax
movslq -0x4c(%rbp),%rcx
movsd  %xmm0,(%rax,%rcx,8)
mov    -0x40(%rbp),%eax
add    -0x54(%rbp),%eax
mov    %eax,-0x40(%rbp)
jmp    12fe <dfft+0x1ce>
mov    -0x54(%rbp),%eax
shl    $0x1,%eax
sub    -0x5c(%rbp),%eax
add    -0x30(%rbp),%eax
mov    %eax,-0x50(%rbp)
mov    -0x54(%rbp),%eax
shl    $0x2,%eax
mov    %eax,-0x54(%rbp)
jmp    12ec <dfft+0x1bc>
jmp    1608 <dfft+0x4d8>
mov    -0x30(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x30(%rbp)
jmp    1267 <dfft+0x137>
jmp    161b <dfft+0x4eb>
mov    -0x34(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x34(%rbp)
jmp    1215 <dfft+0xe5>
movl   $0x1,-0x50(%rbp)
movl   $0x4,-0x54(%rbp)
mov    -0x50(%rbp),%eax
cmp    -0x3c(%rbp),%eax
jge    1738 <dfft+0x608>
mov    -0x50(%rbp),%eax
mov    %eax,-0x40(%rbp)
mov    -0x40(%rbp),%eax
cmp    -0x3c(%rbp),%eax
jg     171e <dfft+0x5ee>
mov    -0x40(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x44(%rbp)
mov    -0x20(%rbp),%rax
movslq -0x40(%rbp),%rcx
movsd  (%rax,%rcx,8),%xmm0
movsd  %xmm0,-0xa0(%rbp)
ff
movsd  -0xa0(%rbp),%xmm0
ff
mov    -0x20(%rbp),%rax
movslq -0x44(%rbp),%rcx
addsd  (%rax,%rcx,8),%xmm0
mov    -0x20(%rbp),%rax
movslq -0x40(%rbp),%rcx
movsd  %xmm0,(%rax,%rcx,8)
movsd  -0xa0(%rbp),%xmm0
ff
mov    -0x20(%rbp),%rax
movslq -0x44(%rbp),%rcx
subsd  (%rax,%rcx,8),%xmm0
mov    -0x20(%rbp),%rax
movslq -0x44(%rbp),%rcx
movsd  %xmm0,(%rax,%rcx,8)
mov    -0x28(%rbp),%rax
movslq -0x40(%rbp),%rcx
movsd  (%rax,%rcx,8),%xmm0
movsd  %xmm0,-0xa0(%rbp)
ff
movsd  -0xa0(%rbp),%xmm0
ff
mov    -0x28(%rbp),%rax
movslq -0x44(%rbp),%rcx
addsd  (%rax,%rcx,8),%xmm0
mov    -0x28(%rbp),%rax
movslq -0x40(%rbp),%rcx
movsd  %xmm0,(%rax,%rcx,8)
movsd  -0xa0(%rbp),%xmm0
ff
mov    -0x28(%rbp),%rax
movslq -0x44(%rbp),%rcx
subsd  (%rax,%rcx,8),%xmm0
mov    -0x28(%rbp),%rax
movslq -0x44(%rbp),%rcx
movsd  %xmm0,(%rax,%rcx,8)
mov    -0x40(%rbp),%eax
add    -0x54(%rbp),%eax
mov    %eax,-0x40(%rbp)
jmp    1649 <dfft+0x519>
mov    -0x54(%rbp),%eax
shl    $0x1,%eax
sub    $0x1,%eax
mov    %eax,-0x50(%rbp)
mov    -0x54(%rbp),%eax
shl    $0x2,%eax
mov    %eax,-0x54(%rbp)
jmp    1637 <dfft+0x507>
movl   $0x1,-0x30(%rbp)
mov    -0x3c(%rbp),%eax
sub    $0x1,%eax
mov    %eax,-0x58(%rbp)
movl   $0x1,-0x2c(%rbp)
mov    -0x2c(%rbp),%eax
cmp    -0x58(%rbp),%eax
jg     183c <dfft+0x70c>
mov    -0x2c(%rbp),%eax
cmp    -0x30(%rbp),%eax
jge    17ef <dfft+0x6bf>
mov    -0x20(%rbp),%rax
movslq -0x30(%rbp),%rcx
movsd  (%rax,%rcx,8),%xmm0
movsd  %xmm0,-0xc8(%rbp)
ff
mov    -0x20(%rbp),%rax
movslq -0x2c(%rbp),%rcx
movsd  (%rax,%rcx,8),%xmm0
mov    -0x20(%rbp),%rax
movslq -0x30(%rbp),%rcx
movsd  %xmm0,(%rax,%rcx,8)
movsd  -0xc8(%rbp),%xmm0
ff
mov    -0x20(%rbp),%rax
movslq -0x2c(%rbp),%rcx
movsd  %xmm0,(%rax,%rcx,8)
mov    -0x28(%rbp),%rax
movslq -0x30(%rbp),%rcx
movsd  (%rax,%rcx,8),%xmm0
movsd  %xmm0,-0xc8(%rbp)
ff
mov    -0x28(%rbp),%rax
movslq -0x2c(%rbp),%rcx
movsd  (%rax,%rcx,8),%xmm0
mov    -0x28(%rbp),%rax
movslq -0x30(%rbp),%rcx
movsd  %xmm0,(%rax,%rcx,8)
movsd  -0xc8(%rbp),%xmm0
ff
mov    -0x28(%rbp),%rax
movslq -0x2c(%rbp),%rcx
movsd  %xmm0,(%rax,%rcx,8)
mov    -0x3c(%rbp),%eax
mov    $0x2,%ecx
cltd
idiv   %ecx
mov    %eax,-0x34(%rbp)
mov    -0x34(%rbp),%eax
cmp    -0x30(%rbp),%eax
jge    1825 <dfft+0x6f5>
mov    -0x30(%rbp),%eax
sub    -0x34(%rbp),%eax
mov    %eax,-0x30(%rbp)
mov    -0x34(%rbp),%eax
mov    $0x2,%ecx
cltd
idiv   %ecx
mov    %eax,-0x34(%rbp)
jmp    17fd <dfft+0x6cd>
mov    -0x30(%rbp),%eax
add    -0x34(%rbp),%eax
mov    %eax,-0x30(%rbp)
mov    -0x2c(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x2c(%rbp)
jmp    174f <dfft+0x61f>
mov    -0x3c(%rbp),%eax
add    $0xd0,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<dfft>:
push   %rbp
push   %r15
push   %r14
push   %r13
push   %r12
push   %rbx
sub    $0x88,%rsp
mov    %rsi,%r9
cmp    $0x3,%edx
jl     116b <dfft+0x3b>
mov    $0x1,%ebx
mov    $0x2,%eax
cs nopw 0x0(%rax,%rax,1)
nopl   (%rax)
add    %eax,%eax
add    $0x1,%ebx
cmp    %edx,%eax
jl     1160 <dfft+0x30>
jmp    1175 <dfft+0x45>
mov    $0x2,%eax
mov    $0x1,%ebx
cmp    %edx,%eax
mov    %r9,0x38(%rsp)
mov    %rdi,0x30(%rsp)
mov    %rax,0x10(%rsp)
je     1391 <dfft+0x261>
jle    1372 <dfft+0x242>
movslq %edx,%rcx
movslq %eax,%r11
mov    %r11,%r14
sub    %rcx,%r14
cmp    $0x4,%r14
jb     12d0 <dfft+0x1a0>
lea    (%rdi,%rcx,8),%rdx
lea    (%r9,%r11,8),%rsi
cmp    %rsi,%rdx
jae    11c6 <dfft+0x96>
lea    (%rdi,%r11,8),%rdx
lea    (%r9,%rcx,8),%rsi
cmp    %rdx,%rsi
jb     12d0 <dfft+0x1a0>
mov    %r14,%r8
and    $0xfffffffffffffffc,%r8
lea    -0x4(%r8),%rdx
mov    %rdx,%rbp
shr    $0x2,%rbp
add    $0x1,%rbp
mov    %ebp,%r10d
and    $0x3,%r10d
cmp    $0xc,%rdx
jae    11f0 <dfft+0xc0>
xor    %eax,%eax
jmp    1278 <dfft+0x148>
and    $0xfffffffffffffffc,%rbp
lea    (%r9,%rcx,8),%rsi
add    $0x70,%rsi
lea    (%rdi,%rcx,8),%rdx
add    $0x70,%rdx
xor    %eax,%eax
xorpd  %xmm0,%xmm0
nopw   0x0(%rax,%rax,1)
movupd %xmm0,-0x70(%rdx,%rax,8)
movupd %xmm0,-0x60(%rdx,%rax,8)
movupd %xmm0,-0x70(%rsi,%rax,8)
movupd %xmm0,-0x60(%rsi,%rax,8)
movupd %xmm0,-0x50(%rdx,%rax,8)
movupd %xmm0,-0x40(%rdx,%rax,8)
movupd %xmm0,-0x50(%rsi,%rax,8)
movupd %xmm0,-0x40(%rsi,%rax,8)
movupd %xmm0,-0x30(%rdx,%rax,8)
movupd %xmm0,-0x20(%rdx,%rax,8)
movupd %xmm0,-0x30(%rsi,%rax,8)
movupd %xmm0,-0x20(%rsi,%rax,8)
movupd %xmm0,-0x10(%rdx,%rax,8)
movupd %xmm0,(%rdx,%rax,8)
movupd %xmm0,-0x10(%rsi,%rax,8)
movupd %xmm0,(%rsi,%rax,8)
add    $0x10,%rax
add    $0xfffffffffffffffc,%rbp
jne    1210 <dfft+0xe0>
test   %r10,%r10
je     12bf <dfft+0x18f>
add    %rcx,%rax
lea    (%r9,%rax,8),%rdx
add    $0x10,%rdx
lea    (%rdi,%rax,8),%rsi
add    $0x10,%rsi
shl    $0x5,%r10
xor    %eax,%eax
xorpd  %xmm0,%xmm0
nopw   0x0(%rax,%rax,1)
movupd %xmm0,-0x10(%rsi,%rax,1)
movupd %xmm0,(%rsi,%rax,1)
movupd %xmm0,-0x10(%rdx,%rax,1)
movupd %xmm0,(%rdx,%rax,1)
add    $0x20,%rax
cmp    %rax,%r10
jne    12a0 <dfft+0x170>
cmp    %r8,%r14
mov    0x10(%rsp),%rax
je     1372 <dfft+0x242>
add    %r8,%rcx
mov    %eax,%ebp
sub    %ecx,%ebp
mov    %rcx,%rsi
not    %rsi
add    %r11,%rsi
and    $0x3,%rbp
je     179e <dfft+0x66e>
nopw   0x0(%rax,%rax,1)
lea    0x1(%rcx),%rdx
movq   $0x0,(%rdi,%rcx,8)
movq   $0x0,(%r9,%rcx,8)
mov    %rdx,%rcx
add    $0xffffffffffffffff,%rbp
jne    12f0 <dfft+0x1c0>
cmp    $0x3,%rsi
jb     1372 <dfft+0x242>
cs nopw 0x0(%rax,%rax,1)
nopl   (%rax)
movq   $0x0,(%rdi,%rdx,8)
movq   $0x0,(%r9,%rdx,8)
movq   $0x0,0x8(%rdi,%rdx,8)
movq   $0x0,0x8(%r9,%rdx,8)
movq   $0x0,0x10(%rdi,%rdx,8)
movq   $0x0,0x10(%r9,%rdx,8)
movq   $0x0,0x18(%rdi,%rdx,8)
movq   $0x0,0x18(%r9,%rdx,8)
lea    0x4(%rdx),%rcx
mov    %rcx,%rdx
cmp    %rcx,%r11
jne    1320 <dfft+0x1f0>
lea    0xcb7(%rip),%rdi
mov    %eax,%esi
xor    %eax,%eax
call   1030 <printf@plt>
mov    0x10(%rsp),%rax
mov    0x30(%rsp),%rdi
mov    0x38(%rsp),%r9
cmp    $0x2,%ebx
jb     1685 <dfft+0x555>
lea    (%rax,%rax,1),%ecx
mov    %rcx,0x8(%rsp)
movslq %eax,%rcx
lea    -0x8(%rdi),%rdx
mov    %rdx,0x50(%rsp)
lea    -0x8(%r9),%rdx
mov    %rdx,0x48(%rsp)
mov    $0x1,%edx
mov    %ebx,0x20(%rsp)
mov    %rcx,0x58(%rsp)
jmp    13e3 <dfft+0x2b3>
nopw   0x0(%rax,%rax,1)
mov    0x24(%rsp),%edx
add    $0x1,%edx
mov    0x20(%rsp),%ebx
cmp    %ebx,%edx
je     1685 <dfft+0x555>
mov    %edx,0x24(%rsp)
mov    0x8(%rsp),%rdx
mov    %edx,%esi
shr    $0x1f,%esi
add    %edx,%esi
sar    %esi
mov    %rsi,0x8(%rsp)
lea    0x7(%rdx),%esi
test   %edx,%edx
cmovns %edx,%esi
cmp    $0x8,%edx
jl     13d0 <dfft+0x2a0>
sar    $0x3,%esi
mov    0x8(%rsp),%rax
xorps  %xmm0,%xmm0
cvtsi2sd %eax,%xmm0
movsd  0xbe2(%rip),%xmm1
divsd  %xmm0,%xmm1
movsd  %xmm1,0x60(%rsp)
add    %eax,%eax
mov    %eax,0x28(%rsp)
mov    %esi,0x2c(%rsp)
movslq %esi,%r13
mov    0x50(%rsp),%rdx
lea    (%rdx,%r13,8),%r12
lea    0x0(,%r13,8),%rax
mov    0x48(%rsp),%rsi
lea    (%rsi,%r13,8),%r15
lea    (%rax,%rax,2),%r14
lea    (%rdx,%r14,1),%rbx
add    %rsi,%r14
shl    $0x4,%r13
lea    (%rdx,%r13,1),%rbp
add    %rsi,%r13
xorpd  %xmm1,%xmm1
mov    $0x1,%edx
movsd  0xb92(%rip),%xmm0
jmp    14aa <dfft+0x37a>
nopl   0x0(%rax,%rax,1)
movsd  0x60(%rsp),%xmm1
movsd  0x80(%rsp),%xmm0
mulsd  %xmm0,%xmm1
addsd  0xb6d(%rip),%xmm0
lea    0x1(%r11),%edx
cmp    0x2c(%rsp),%r11d
je     13d0 <dfft+0x2a0>
movsd  %xmm1,0x18(%rsp)
mov    %rdx,0x78(%rsp)
movsd  %xmm0,0x80(%rsp)
movapd %xmm1,%xmm0
mulsd  0xb46(%rip),%xmm0
movsd  %xmm0,0x40(%rsp)
movapd %xmm1,%xmm0
call   1050 <cos@plt>
movsd  %xmm0,0x70(%rsp)
movsd  0x18(%rsp),%xmm0
call   1040 <sin@plt>
movsd  %xmm0,0x18(%rsp)
movsd  0x40(%rsp),%xmm0
call   1050 <cos@plt>
movsd  %xmm0,0x68(%rsp)
movsd  0x40(%rsp),%xmm0
call   1040 <sin@plt>
movsd  0x68(%rsp),%xmm10
movsd  0x18(%rsp),%xmm9
movsd  0x70(%rsp),%xmm8
mov    0x78(%rsp),%r11
movapd 0xaf2(%rip),%xmm7
mov    0x58(%rsp),%rcx
mov    0x10(%rsp),%rax
mov    0x30(%rsp),%rdi
mov    0x38(%rsp),%r9
cmp    %eax,%r11d
jge    1480 <dfft+0x350>
mov    %r11d,%r8d
sub    0x8(%rsp),%r8d
mov    %r11d,%edx
mov    0x28(%rsp),%esi
mov    %esi,%r10d
jmp    1570 <dfft+0x440>
nop
lea    (%r8,%r10,2),%edx
shl    $0x2,%r10d
cmp    %eax,%edx
jge    1480 <dfft+0x350>
cmp    %eax,%edx
jge    1560 <dfft+0x430>
movslq %edx,%rdx
movslq %r10d,%rsi
nopw   0x0(%rax,%rax,1)
movsd  -0x8(%rdi,%rdx,8),%xmm1
movsd  0x0(%rbp,%rdx,8),%xmm2
movapd %xmm1,%xmm3
subsd  %xmm2,%xmm3
addsd  %xmm2,%xmm1
movsd  %xmm1,-0x8(%rdi,%rdx,8)
movsd  (%r12,%rdx,8),%xmm1
movsd  (%rbx,%rdx,8),%xmm2
movapd %xmm1,%xmm4
subsd  %xmm2,%xmm4
addsd  %xmm2,%xmm1
movsd  %xmm1,(%r12,%rdx,8)
movsd  -0x8(%r9,%rdx,8),%xmm2
movsd  0x0(%r13,%rdx,8),%xmm5
movapd %xmm2,%xmm1
subsd  %xmm5,%xmm1
addsd  %xmm5,%xmm2
movsd  %xmm2,-0x8(%r9,%rdx,8)
movsd  (%r15,%rdx,8),%xmm2
movsd  (%r14,%rdx,8),%xmm5
movapd %xmm2,%xmm6
subsd  %xmm5,%xmm6
addsd  %xmm5,%xmm2
movsd  %xmm2,(%r15,%rdx,8)
movapd %xmm3,%xmm2
subsd  %xmm6,%xmm2
addsd  %xmm3,%xmm6
movapd %xmm4,%xmm3
subsd  %xmm1,%xmm3
addsd  %xmm4,%xmm1
movapd %xmm9,%xmm4
mulsd  %xmm3,%xmm4
xorpd  %xmm7,%xmm3
movapd %xmm9,%xmm5
mulsd  %xmm6,%xmm5
mulsd  %xmm8,%xmm6
subsd  %xmm4,%xmm6
movsd  %xmm6,0x0(%rbp,%rdx,8)
mulsd  %xmm8,%xmm3
subsd  %xmm5,%xmm3
movsd  %xmm3,0x0(%r13,%rdx,8)
movapd %xmm0,%xmm3
mulsd  %xmm1,%xmm3
movapd %xmm0,%xmm4
mulsd  %xmm2,%xmm4
mulsd  %xmm10,%xmm2
addsd  %xmm3,%xmm2
movsd  %xmm2,(%rbx,%rdx,8)
mulsd  %xmm10,%xmm1
subsd  %xmm4,%xmm1
movsd  %xmm1,(%r14,%rdx,8)
add    %rsi,%rdx
cmp    %rcx,%rdx
jl     1580 <dfft+0x450>
jmp    1560 <dfft+0x430>
cmp    $0x2,%eax
jl     178c <dfft+0x65c>
mov    %eax,%ebx
mov    $0x4,%ecx
mov    $0x1,%edx
jmp    16b0 <dfft+0x580>
nopl   0x0(%rax)
lea    (%rcx,%rcx,1),%esi
lea    (%rcx,%rcx,1),%edx
add    $0xffffffff,%edx
shl    $0x2,%ecx
cmp    %eax,%esi
jg     1712 <dfft+0x5e2>
cmp    %eax,%edx
jg     16a0 <dfft+0x570>
movslq %edx,%rdx
movslq %ecx,%rsi
nopw   0x0(%rax,%rax,1)
movsd  -0x8(%rdi,%rdx,8),%xmm0
movsd  (%rdi,%rdx,8),%xmm1
movapd %xmm0,%xmm2
addsd  %xmm1,%xmm2
movsd  %xmm2,-0x8(%rdi,%rdx,8)
subsd  %xmm1,%xmm0
movsd  %xmm0,(%rdi,%rdx,8)
movsd  -0x8(%r9,%rdx,8),%xmm0
movsd  (%r9,%rdx,8),%xmm1
movapd %xmm0,%xmm2
addsd  %xmm1,%xmm2
movsd  %xmm2,-0x8(%r9,%rdx,8)
subsd  %xmm1,%xmm0
movsd  %xmm0,(%r9,%rdx,8)
add    %rsi,%rdx
cmp    %rbx,%rdx
jle    16c0 <dfft+0x590>
jmp    16a0 <dfft+0x570>
cmp    $0x2,%eax
jl     178c <dfft+0x65c>
mov    $0x1,%edx
mov    $0x1,%r8d
cs nopw 0x0(%rax,%rax,1)
nopl   0x0(%rax)
movslq %edx,%rsi
cmp    %rsi,%r8
jge    176e <dfft+0x63e>
movsd  -0x8(%rdi,%rsi,8),%xmm0
movsd  -0x8(%rdi,%r8,8),%xmm1
movsd  %xmm1,-0x8(%rdi,%rsi,8)
movsd  %xmm0,-0x8(%rdi,%r8,8)
movsd  -0x8(%r9,%rsi,8),%xmm0
movsd  -0x8(%r9,%r8,8),%xmm1
movsd  %xmm1,-0x8(%r9,%rsi,8)
movsd  %xmm0,-0x8(%r9,%r8,8)
mov    %eax,%ecx
mov    %edx,%esi
mov    %ecx,%ebp
shr    $0x1f,%ebp
add    %ebp,%ecx
sar    %ecx
sub    %ecx,%edx
jg     1770 <dfft+0x640>
add    %ecx,%esi
add    $0x1,%r8
mov    %esi,%edx
cmp    %rbx,%r8
jne    1730 <dfft+0x600>
add    $0x88,%rsp
pop    %rbx
pop    %r12
pop    %r13
pop    %r14
pop    %r15
pop    %rbp
ret
mov    %rcx,%rdx
cmp    $0x3,%rsi
jae    1320 <dfft+0x1f0>
jmp    1372 <dfft+0x242>

LLVM IR (-O0):
@.str = [18 x i8] c"\0Ause %d point fft\00"
define i32 @dfft(double* %0, double* %1, i32 %2) {
%4 = alloca double*
%5 = alloca double*
%6 = alloca i32
%7 = alloca double*
%8 = alloca double*
%9 = alloca i32
%10 = alloca i32
%11 = alloca i32
%12 = alloca i32
%13 = alloca i32
%14 = alloca i32
%15 = alloca i32
%16 = alloca i32
%17 = alloca i32
%18 = alloca i32
%19 = alloca i32
%20 = alloca i32
%21 = alloca i32
%22 = alloca i32
%23 = alloca double
%24 = alloca double
%25 = alloca double
%26 = alloca double
%27 = alloca double
%28 = alloca double
%29 = alloca double
%30 = alloca double
%31 = alloca double
%32 = alloca double
%33 = alloca double
%34 = alloca double
%35 = alloca double
%36 = alloca double
store double* %0, double** %4
store double* %1, double** %5
store i32 %2, i32* %6
%37 = load double*, double** %4
%38 = getelementptr inbounds double, double* %37, i64 -1
store double* %38, double** %7
%39 = load double*, double** %5
%40 = getelementptr inbounds double, double* %39, i64 -1
store double* %40, double** %8
store i32 2, i32* %9
store i32 1, i32* %12
br label %41
41: ; preds = %45, %3
%42 = load i32, i32* %9
%43 = load i32, i32* %6
%44 = icmp slt i32 %42, %43
br i1 %44, label %45, label %51
45: ; preds = %41
%46 = load i32, i32* %9
%47 = load i32, i32* %9
%48 = add nsw i32 %46, %47
store i32 %48, i32* %9
%49 = load i32, i32* %12
%50 = add nsw i32 %49, 1
store i32 %50, i32* %12
br label %41
51: ; preds = %41
%52 = load i32, i32* %9
store i32 %52, i32* %13
%53 = load i32, i32* %13
%54 = load i32, i32* %6
%55 = icmp ne i32 %53, %54
br i1 %55, label %56, label %78
56: ; preds = %51
%57 = load i32, i32* %6
%58 = add nsw i32 %57, 1
store i32 %58, i32* %9
br label %59
59: ; preds = %72, %56
%60 = load i32, i32* %9
%61 = load i32, i32* %13
%62 = icmp sle i32 %60, %61
br i1 %62, label %63, label %75
63: ; preds = %59
%64 = load double*, double** %7
%65 = load i32, i32* %9
%66 = sext i32 %65 to i64
%67 = getelementptr inbounds double, double* %64, i64 %66
store double 0.000000e+00, double* %67
%68 = load double*, double** %8
%69 = load i32, i32* %9
%70 = sext i32 %69 to i64
%71 = getelementptr inbounds double, double* %68, i64 %70
store double 0.000000e+00, double* %71
br label %72
72: ; preds = %63
%73 = load i32, i32* %9
%74 = add nsw i32 %73, 1
store i32 %74, i32* %9
br label %59
75: ; preds = %59
%76 = load i32, i32* %13
%77 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([18 x i8], [18 x i8]* @.str, i64 0, i64 0), i32 %76)
br label %78
78: ; preds = %75, %51
%79 = load i32, i32* %13
%80 = load i32, i32* %13
%81 = add nsw i32 %79, %80
store i32 %81, i32* %21
store double 0x401921FB54442D18, double* %36
store i32 1, i32* %11
br label %82
82: ; preds = %317, %78
%83 = load i32, i32* %11
%84 = load i32, i32* %12
%85 = sub nsw i32 %84, 1
%86 = icmp sle i32 %83, %85
br i1 %86, label %87, label %320
87: ; preds = %82
%88 = load i32, i32* %21
%89 = sdiv i32 %88, 2
store i32 %89, i32* %21
%90 = load i32, i32* %21
%91 = sdiv i32 %90, 4
store i32 %91, i32* %22
%92 = load double, double* %36
%93 = load i32, i32* %21
%94 = sitofp i32 %93 to double
%95 = fdiv double %92, %94
store double %95, double* %24
store double 0.000000e+00, double* %23
store i32 1, i32* %10
br label %96
96: ; preds = %313, %87
%97 = load i32, i32* %10
%98 = load i32, i32* %22
%99 = icmp sle i32 %97, %98
br i1 %99, label %100, label %316
100: ; preds = %96
%101 = load double, double* %23
%102 = fmul double 3.000000e+00, %101
store double %102, double* %25
%103 = load double, double* %23
%104 = call double @cos(double %103)
store double %104, double* %26
%105 = load double, double* %23
%106 = call double @sin(double %105)
store double %106, double* %27
%107 = load double, double* %25
%108 = call double @cos(double %107)
store double %108, double* %28
%109 = load double, double* %25
%110 = call double @sin(double %109)
store double %110, double* %29
%111 = load double, double* %24
%112 = load i32, i32* %10
%113 = sitofp i32 %112 to double
%114 = fmul double %111, %113
store double %114, double* %23
%115 = load i32, i32* %10
store i32 %115, i32* %18
%116 = load i32, i32* %21
%117 = mul nsw i32 2, %116
store i32 %117, i32* %19
br label %118
118: ; preds = %303, %100
%119 = load i32, i32* %18
%120 = load i32, i32* %13
%121 = icmp slt i32 %119, %120
br i1 %121, label %122, label %312
122: ; preds = %118
%123 = load i32, i32* %18
store i32 %123, i32* %14
br label %124
124: ; preds = %299, %122
%125 = load i32, i32* %14
%126 = load i32, i32* %13
%127 = sub nsw i32 %126, 1
%128 = icmp sle i32 %125, %127
br i1 %128, label %129, label %303
129: ; preds = %124
%130 = load i32, i32* %14
%131 = load i32, i32* %22
%132 = add nsw i32 %130, %131
store i32 %132, i32* %15
%133 = load i32, i32* %15
%134 = load i32, i32* %22
%135 = add nsw i32 %133, %134
store i32 %135, i32* %16
%136 = load i32, i32* %16
%137 = load i32, i32* %22
%138 = add nsw i32 %136, %137
store i32 %138, i32* %17
%139 = load double*, double** %7
%140 = load i32, i32* %14
%141 = sext i32 %140 to i64
%142 = getelementptr inbounds double, double* %139, i64 %141
%143 = load double, double* %142
%144 = load double*, double** %7
%145 = load i32, i32* %16
%146 = sext i32 %145 to i64
%147 = getelementptr inbounds double, double* %144, i64 %146
%148 = load double, double* %147
%149 = fsub double %143, %148
store double %149, double* %30
%150 = load double*, double** %7
%151 = load i32, i32* %14
%152 = sext i32 %151 to i64
%153 = getelementptr inbounds double, double* %150, i64 %152
%154 = load double, double* %153
%155 = load double*, double** %7
%156 = load i32, i32* %16
%157 = sext i32 %156 to i64
%158 = getelementptr inbounds double, double* %155, i64 %157
%159 = load double, double* %158
%160 = fadd double %154, %159
%161 = load double*, double** %7
%162 = load i32, i32* %14
%163 = sext i32 %162 to i64
%164 = getelementptr inbounds double, double* %161, i64 %163
store double %160, double* %164
%165 = load double*, double** %7
%166 = load i32, i32* %15
%167 = sext i32 %166 to i64
%168 = getelementptr inbounds double, double* %165, i64 %167
%169 = load double, double* %168
%170 = load double*, double** %7
%171 = load i32, i32* %17
%172 = sext i32 %171 to i64
%173 = getelementptr inbounds double, double* %170, i64 %172
%174 = load double, double* %173
%175 = fsub double %169, %174
store double %175, double* %31
%176 = load double*, double** %7
%177 = load i32, i32* %15
%178 = sext i32 %177 to i64
%179 = getelementptr inbounds double, double* %176, i64 %178
%180 = load double, double* %179
%181 = load double*, double** %7
%182 = load i32, i32* %17
%183 = sext i32 %182 to i64
%184 = getelementptr inbounds double, double* %181, i64 %183
%185 = load double, double* %184
%186 = fadd double %180, %185
%187 = load double*, double** %7
%188 = load i32, i32* %15
%189 = sext i32 %188 to i64
%190 = getelementptr inbounds double, double* %187, i64 %189
store double %186, double* %190
%191 = load double*, double** %8
%192 = load i32, i32* %14
%193 = sext i32 %192 to i64
%194 = getelementptr inbounds double, double* %191, i64 %193
%195 = load double, double* %194
%196 = load double*, double** %8
%197 = load i32, i32* %16
%198 = sext i32 %197 to i64
%199 = getelementptr inbounds double, double* %196, i64 %198
%200 = load double, double* %199
%201 = fsub double %195, %200
store double %201, double* %32
%202 = load double*, double** %8
%203 = load i32, i32* %14
%204 = sext i32 %203 to i64
%205 = getelementptr inbounds double, double* %202, i64 %204
%206 = load double, double* %205
%207 = load double*, double** %8
%208 = load i32, i32* %16
%209 = sext i32 %208 to i64
%210 = getelementptr inbounds double, double* %207, i64 %209
%211 = load double, double* %210
%212 = fadd double %206, %211
%213 = load double*, double** %8
%214 = load i32, i32* %14
%215 = sext i32 %214 to i64
%216 = getelementptr inbounds double, double* %213, i64 %215
store double %212, double* %216
%217 = load double*, double** %8
%218 = load i32, i32* %15
%219 = sext i32 %218 to i64
%220 = getelementptr inbounds double, double* %217, i64 %219
%221 = load double, double* %220
%222 = load double*, double** %8
%223 = load i32, i32* %17
%224 = sext i32 %223 to i64
%225 = getelementptr inbounds double, double* %222, i64 %224
%226 = load double, double* %225
%227 = fsub double %221, %226
store double %227, double* %33
%228 = load double*, double** %8
%229 = load i32, i32* %15
%230 = sext i32 %229 to i64
%231 = getelementptr inbounds double, double* %228, i64 %230
%232 = load double, double* %231
%233 = load double*, double** %8
%234 = load i32, i32* %17
%235 = sext i32 %234 to i64
%236 = getelementptr inbounds double, double* %233, i64 %235
%237 = load double, double* %236
%238 = fadd double %232, %237
%239 = load double*, double** %8
%240 = load i32, i32* %15
%241 = sext i32 %240 to i64
%242 = getelementptr inbounds double, double* %239, i64 %241
store double %238, double* %242
%243 = load double, double* %30
%244 = load double, double* %33
%245 = fsub double %243, %244
store double %245, double* %34
%246 = load double, double* %30
%247 = load double, double* %33
%248 = fadd double %246, %247
store double %248, double* %30
%249 = load double, double* %31
%250 = load double, double* %32
%251 = fsub double %249, %250
store double %251, double* %33
%252 = load double, double* %31
%253 = load double, double* %32
%254 = fadd double %252, %253
store double %254, double* %31
%255 = load double, double* %30
%256 = load double, double* %26
%257 = load double, double* %33
%258 = load double, double* %27
%259 = fmul double %257, %258
%260 = fneg double %259
%261 = call double @llvm.fmuladd.f64(double %255, double %256, double %260)
%262 = load double*, double** %7
%263 = load i32, i32* %16
%264 = sext i32 %263 to i64
%265 = getelementptr inbounds double, double* %262, i64 %264
store double %261, double* %265
%266 = load double, double* %33
%267 = fneg double %266
%268 = load double, double* %26
%269 = load double, double* %30
%270 = load double, double* %27
%271 = fmul double %269, %270
%272 = fneg double %271
%273 = call double @llvm.fmuladd.f64(double %267, double %268, double %272)
%274 = load double*, double** %8
%275 = load i32, i32* %16
%276 = sext i32 %275 to i64
%277 = getelementptr inbounds double, double* %274, i64 %276
store double %273, double* %277
%278 = load double, double* %34
%279 = load double, double* %28
%280 = load double, double* %31
%281 = load double, double* %29
%282 = fmul double %280, %281
%283 = call double @llvm.fmuladd.f64(double %278, double %279, double %282)
%284 = load double*, double** %7
%285 = load i32, i32* %17
%286 = sext i32 %285 to i64
%287 = getelementptr inbounds double, double* %284, i64 %286
store double %283, double* %287
%288 = load double, double* %31
%289 = load double, double* %28
%290 = load double, double* %34
%291 = load double, double* %29
%292 = fmul double %290, %291
%293 = fneg double %292
%294 = call double @llvm.fmuladd.f64(double %288, double %289, double %293)
%295 = load double*, double** %8
%296 = load i32, i32* %17
%297 = sext i32 %296 to i64
%298 = getelementptr inbounds double, double* %295, i64 %297
store double %294, double* %298
br label %299
299: ; preds = %129
%300 = load i32, i32* %14
%301 = load i32, i32* %19
%302 = add nsw i32 %300, %301
store i32 %302, i32* %14
br label %124
303: ; preds = %124
%304 = load i32, i32* %19
%305 = mul nsw i32 2, %304
%306 = load i32, i32* %21
%307 = sub nsw i32 %305, %306
%308 = load i32, i32* %10
%309 = add nsw i32 %307, %308
store i32 %309, i32* %18
%310 = load i32, i32* %19
%311 = mul nsw i32 4, %310
store i32 %311, i32* %19
br label %118
312: ; preds = %118
br label %313
313: ; preds = %312
%314 = load i32, i32* %10
%315 = add nsw i32 %314, 1
store i32 %315, i32* %10
br label %96
316: ; preds = %96
br label %317
317: ; preds = %316
%318 = load i32, i32* %11
%319 = add nsw i32 %318, 1
store i32 %319, i32* %11
br label %82
320: ; preds = %82
store i32 1, i32* %18
store i32 4, i32* %19
br label %321
321: ; preds = %392, %320
%322 = load i32, i32* %18
%323 = load i32, i32* %13
%324 = icmp slt i32 %322, %323
br i1 %324, label %325, label %398
325: ; preds = %321
%326 = load i32, i32* %18
store i32 %326, i32* %14
br label %327
327: ; preds = %388, %325
%328 = load i32, i32* %14
%329 = load i32, i32* %13
%330 = icmp sle i32 %328, %329
br i1 %330, label %331, label %392
331: ; preds = %327
%332 = load i32, i32* %14
%333 = add nsw i32 %332, 1
store i32 %333, i32* %15
%334 = load double*, double** %7
%335 = load i32, i32* %14
%336 = sext i32 %335 to i64
%337 = getelementptr inbounds double, double* %334, i64 %336
%338 = load double, double* %337
store double %338, double* %30
%339 = load double, double* %30
%340 = load double*, double** %7
%341 = load i32, i32* %15
%342 = sext i32 %341 to i64
%343 = getelementptr inbounds double, double* %340, i64 %342
%344 = load double, double* %343
%345 = fadd double %339, %344
%346 = load double*, double** %7
%347 = load i32, i32* %14
%348 = sext i32 %347 to i64
%349 = getelementptr inbounds double, double* %346, i64 %348
store double %345, double* %349
%350 = load double, double* %30
%351 = load double*, double** %7
%352 = load i32, i32* %15
%353 = sext i32 %352 to i64
%354 = getelementptr inbounds double, double* %351, i64 %353
%355 = load double, double* %354
%356 = fsub double %350, %355
%357 = load double*, double** %7
%358 = load i32, i32* %15
%359 = sext i32 %358 to i64
%360 = getelementptr inbounds double, double* %357, i64 %359
store double %356, double* %360
%361 = load double*, double** %8
%362 = load i32, i32* %14
%363 = sext i32 %362 to i64
%364 = getelementptr inbounds double, double* %361, i64 %363
%365 = load double, double* %364
store double %365, double* %30
%366 = load double, double* %30
%367 = load double*, double** %8
%368 = load i32, i32* %15
%369 = sext i32 %368 to i64
%370 = getelementptr inbounds double, double* %367, i64 %369
%371 = load double, double* %370
%372 = fadd double %366, %371
%373 = load double*, double** %8
%374 = load i32, i32* %14
%375 = sext i32 %374 to i64
%376 = getelementptr inbounds double, double* %373, i64 %375
store double %372, double* %376
%377 = load double, double* %30
%378 = load double*, double** %8
%379 = load i32, i32* %15
%380 = sext i32 %379 to i64
%381 = getelementptr inbounds double, double* %378, i64 %380
%382 = load double, double* %381
%383 = fsub double %377, %382
%384 = load double*, double** %8
%385 = load i32, i32* %15
%386 = sext i32 %385 to i64
%387 = getelementptr inbounds double, double* %384, i64 %386
store double %383, double* %387
br label %388
388: ; preds = %331
%389 = load i32, i32* %14
%390 = load i32, i32* %19
%391 = add nsw i32 %389, %390
store i32 %391, i32* %14
br label %327
392: ; preds = %327
%393 = load i32, i32* %19
%394 = mul nsw i32 2, %393
%395 = sub nsw i32 %394, 1
store i32 %395, i32* %18
%396 = load i32, i32* %19
%397 = mul nsw i32 4, %396
store i32 %397, i32* %19
br label %321
398: ; preds = %321
store i32 1, i32* %10
%399 = load i32, i32* %13
%400 = sub nsw i32 %399, 1
store i32 %400, i32* %20
store i32 1, i32* %9
br label %401
401: ; preds = %465, %398
%402 = load i32, i32* %9
%403 = load i32, i32* %20
%404 = icmp sle i32 %402, %403
br i1 %404, label %405, label %468
405: ; preds = %401
%406 = load i32, i32* %9
%407 = load i32, i32* %10
%408 = icmp slt i32 %406, %407
br i1 %408, label %409, label %448
409: ; preds = %405
%410 = load double*, double** %7
%411 = load i32, i32* %10
%412 = sext i32 %411 to i64
%413 = getelementptr inbounds double, double* %410, i64 %412
%414 = load double, double* %413
store double %414, double* %35
%415 = load double*, double** %7
%416 = load i32, i32* %9
%417 = sext i32 %416 to i64
%418 = getelementptr inbounds double, double* %415, i64 %417
%419 = load double, double* %418
%420 = load double*, double** %7
%421 = load i32, i32* %10
%422 = sext i32 %421 to i64
%423 = getelementptr inbounds double, double* %420, i64 %422
store double %419, double* %423
%424 = load double, double* %35
%425 = load double*, double** %7
%426 = load i32, i32* %9
%427 = sext i32 %426 to i64
%428 = getelementptr inbounds double, double* %425, i64 %427
store double %424, double* %428
%429 = load double*, double** %8
%430 = load i32, i32* %10
%431 = sext i32 %430 to i64
%432 = getelementptr inbounds double, double* %429, i64 %431
%433 = load double, double* %432
store double %433, double* %35
%434 = load double*, double** %8
%435 = load i32, i32* %9
%436 = sext i32 %435 to i64
%437 = getelementptr inbounds double, double* %434, i64 %436
%438 = load double, double* %437
%439 = load double*, double** %8
%440 = load i32, i32* %10
%441 = sext i32 %440 to i64
%442 = getelementptr inbounds double, double* %439, i64 %441
store double %438, double* %442
%443 = load double, double* %35
%444 = load double*, double** %8
%445 = load i32, i32* %9
%446 = sext i32 %445 to i64
%447 = getelementptr inbounds double, double* %444, i64 %446
store double %443, double* %447
br label %448
448: ; preds = %409, %405
%449 = load i32, i32* %13
%450 = sdiv i32 %449, 2
store i32 %450, i32* %11
br label %451
451: ; preds = %455, %448
%452 = load i32, i32* %11
%453 = load i32, i32* %10
%454 = icmp slt i32 %452, %453
br i1 %454, label %455, label %461
455: ; preds = %451
%456 = load i32, i32* %10
%457 = load i32, i32* %11
%458 = sub nsw i32 %456, %457
store i32 %458, i32* %10
%459 = load i32, i32* %11
%460 = sdiv i32 %459, 2
store i32 %460, i32* %11
br label %451
461: ; preds = %451
%462 = load i32, i32* %10
%463 = load i32, i32* %11
%464 = add nsw i32 %462, %463
store i32 %464, i32* %10
br label %465
465: ; preds = %461
%466 = load i32, i32* %9
%467 = add nsw i32 %466, 1
store i32 %467, i32* %9
br label %401
468: ; preds = %401
%469 = load i32, i32* %13
ret i32 %469
}

LLVM IR (-O2):
@.str = [18 x i8] c"\0Ause %d point fft\00"
define i32 @dfft(double* nocapture %0, double* nocapture %1, i32 %2) {
%4 = getelementptr inbounds double, double* %0, i64 -1
%5 = getelementptr inbounds double, double* %1, i64 -1
%6 = icmp sgt i32 %2, 2
br i1 %6, label %7, label %13
7: ; preds = %3, %7
%8 = phi i32 [ %10, %7 ], [ 2, %3 ]
%9 = phi i32 [ %11, %7 ], [ 1, %3 ]
%10 = shl nsw i32 %8, 1
%11 = add nuw nsw i32 %9, 1
%12 = icmp slt i32 %10, %2
br i1 %12, label %7, label %13
13: ; preds = %7, %3
%14 = phi i32 [ 1, %3 ], [ %11, %7 ]
%15 = phi i32 [ 2, %3 ], [ %10, %7 ]
%16 = icmp eq i32 %15, %2
br i1 %16, label %142, label %17
17: ; preds = %13
%18 = icmp sgt i32 %15, %2
br i1 %18, label %19, label %140
19: ; preds = %17
%20 = sext i32 %2 to i64
%21 = sext i32 %15 to i64
%22 = sub nsw i64 %21, %20
%23 = icmp ult i64 %22, 4
br i1 %23, label %107, label %24
24: ; preds = %19
%25 = getelementptr double, double* %0, i64 %20
%26 = getelementptr double, double* %0, i64 %21
%27 = getelementptr double, double* %1, i64 %20
%28 = getelementptr double, double* %1, i64 %21
%29 = icmp ult double* %25, %28
%30 = icmp ult double* %27, %26
%31 = and i1 %29, %30
br i1 %31, label %107, label %32
32: ; preds = %24
%33 = and i64 %22, -4
%34 = add nsw i64 %33, %20
%35 = add nsw i64 %33, -4
%36 = lshr exact i64 %35, 2
%37 = add nuw nsw i64 %36, 1
%38 = and i64 %37, 3
%39 = icmp ult i64 %35, 12
br i1 %39, label %87, label %40
40: ; preds = %32
%41 = and i64 %37, 9223372036854775804
br label %42
42: ; preds = %42, %40
%43 = phi i64 [ 0, %40 ], [ %84, %42 ]
%44 = phi i64 [ 0, %40 ], [ %85, %42 ]
%45 = add i64 %43, %20
%46 = getelementptr inbounds double, double* %0, i64 %45
%47 = bitcast double* %46 to <2 x double>*
store <2 x double> zeroinitializer, <2 x double>* %47
%48 = getelementptr inbounds double, double* %46, i64 2
%49 = bitcast double* %48 to <2 x double>*
store <2 x double> zeroinitializer, <2 x double>* %49
%50 = getelementptr inbounds double, double* %1, i64 %45
%51 = bitcast double* %50 to <2 x double>*
store <2 x double> zeroinitializer, <2 x double>* %51
%52 = getelementptr inbounds double, double* %50, i64 2
%53 = bitcast double* %52 to <2 x double>*
store <2 x double> zeroinitializer, <2 x double>* %53
%54 = or i64 %43, 4
%55 = add i64 %54, %20
%56 = getelementptr inbounds double, double* %0, i64 %55
%57 = bitcast double* %56 to <2 x double>*
store <2 x double> zeroinitializer, <2 x double>* %57
%58 = getelementptr inbounds double, double* %56, i64 2
%59 = bitcast double* %58 to <2 x double>*
store <2 x double> zeroinitializer, <2 x double>* %59
%60 = getelementptr inbounds double, double* %1, i64 %55
%61 = bitcast double* %60 to <2 x double>*
store <2 x double> zeroinitializer, <2 x double>* %61
%62 = getelementptr inbounds double, double* %60, i64 2
%63 = bitcast double* %62 to <2 x double>*
store <2 x double> zeroinitializer, <2 x double>* %63
%64 = or i64 %43, 8
%65 = add i64 %64, %20
%66 = getelementptr inbounds double, double* %0, i64 %65
%67 = bitcast double* %66 to <2 x double>*
store <2 x double> zeroinitializer, <2 x double>* %67
%68 = getelementptr inbounds double, double* %66, i64 2
%69 = bitcast double* %68 to <2 x double>*
store <2 x double> zeroinitializer, <2 x double>* %69
%70 = getelementptr inbounds double, double* %1, i64 %65
%71 = bitcast double* %70 to <2 x double>*
store <2 x double> zeroinitializer, <2 x double>* %71
%72 = getelementptr inbounds double, double* %70, i64 2
%73 = bitcast double* %72 to <2 x double>*
store <2 x double> zeroinitializer, <2 x double>* %73
%74 = or i64 %43, 12
%75 = add i64 %74, %20
%76 = getelementptr inbounds double, double* %0, i64 %75
%77 = bitcast double* %76 to <2 x double>*
store <2 x double> zeroinitializer, <2 x double>* %77
%78 = getelementptr inbounds double, double* %76, i64 2
%79 = bitcast double* %78 to <2 x double>*
store <2 x double> zeroinitializer, <2 x double>* %79
%80 = getelementptr inbounds double, double* %1, i64 %75
%81 = bitcast double* %80 to <2 x double>*
store <2 x double> zeroinitializer, <2 x double>* %81
%82 = getelementptr inbounds double, double* %80, i64 2
%83 = bitcast double* %82 to <2 x double>*
store <2 x double> zeroinitializer, <2 x double>* %83
%84 = add nuw i64 %43, 16
%85 = add nuw i64 %44, 4
%86 = icmp eq i64 %85, %41
br i1 %86, label %87, label %42
87: ; preds = %42, %32
%88 = phi i64 [ 0, %32 ], [ %84, %42 ]
%89 = icmp eq i64 %38, 0
br i1 %89, label %105, label %90
90: ; preds = %87, %90
%91 = phi i64 [ %102, %90 ], [ %88, %87 ]
%92 = phi i64 [ %103, %90 ], [ 0, %87 ]
%93 = add i64 %91, %20
%94 = getelementptr inbounds double, double* %0, i64 %93
%95 = bitcast double* %94 to <2 x double>*
store <2 x double> zeroinitializer, <2 x double>* %95
%96 = getelementptr inbounds double, double* %94, i64 2
%97 = bitcast double* %96 to <2 x double>*
store <2 x double> zeroinitializer, <2 x double>* %97
%98 = getelementptr inbounds double, double* %1, i64 %93
%99 = bitcast double* %98 to <2 x double>*
store <2 x double> zeroinitializer, <2 x double>* %99
%100 = getelementptr inbounds double, double* %98, i64 2
%101 = bitcast double* %100 to <2 x double>*
store <2 x double> zeroinitializer, <2 x double>* %101
%102 = add nuw i64 %91, 4
%103 = add i64 %92, 1
%104 = icmp eq i64 %103, %38
br i1 %104, label %105, label %90
105: ; preds = %90, %87
%106 = icmp eq i64 %22, %33
br i1 %106, label %140, label %107
107: ; preds = %24, %19, %105
%108 = phi i64 [ %20, %24 ], [ %20, %19 ], [ %34, %105 ]
%109 = sub nsw i64 %21, %108
%110 = xor i64 %108, -1
%111 = add nsw i64 %110, %21
%112 = and i64 %109, 3
%113 = icmp eq i64 %112, 0
br i1 %113, label %122, label %114
114: ; preds = %107, %114
%115 = phi i64 [ %117, %114 ], [ %108, %107 ]
%116 = phi i64 [ %120, %114 ], [ 0, %107 ]
%117 = add nsw i64 %115, 1
%118 = getelementptr inbounds double, double* %0, i64 %115
store double 0.000000e+00, double* %118
%119 = getelementptr inbounds double, double* %1, i64 %115
store double 0.000000e+00, double* %119
%120 = add i64 %116, 1
%121 = icmp eq i64 %120, %112
br i1 %121, label %122, label %114
122: ; preds = %114, %107
%123 = phi i64 [ %108, %107 ], [ %117, %114 ]
%124 = icmp ult i64 %111, 3
br i1 %124, label %140, label %125
125: ; preds = %122, %125
%126 = phi i64 [ %136, %125 ], [ %123, %122 ]
%127 = add nsw i64 %126, 1
%128 = getelementptr inbounds double, double* %0, i64 %126
store double 0.000000e+00, double* %128
%129 = getelementptr inbounds double, double* %1, i64 %126
store double 0.000000e+00, double* %129
%130 = add nsw i64 %126, 2
%131 = getelementptr inbounds double, double* %0, i64 %127
store double 0.000000e+00, double* %131
%132 = getelementptr inbounds double, double* %1, i64 %127
store double 0.000000e+00, double* %132
%133 = add nsw i64 %126, 3
%134 = getelementptr inbounds double, double* %0, i64 %130
store double 0.000000e+00, double* %134
%135 = getelementptr inbounds double, double* %1, i64 %130
store double 0.000000e+00, double* %135
%136 = add nsw i64 %126, 4
%137 = getelementptr inbounds double, double* %0, i64 %133
store double 0.000000e+00, double* %137
%138 = getelementptr inbounds double, double* %1, i64 %133
store double 0.000000e+00, double* %138
%139 = icmp eq i64 %136, %21
br i1 %139, label %140, label %125
140: ; preds = %122, %125, %105, %17
%141 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([18 x i8], [18 x i8]* @.str, i64 0, i64 0), i32 %15)
br label %142
142: ; preds = %140, %13
%143 = icmp ugt i32 %14, 1
br i1 %143, label %144, label %147
144: ; preds = %142
%145 = shl nsw i32 %15, 1
%146 = sext i32 %15 to i64
br label %151
147: ; preds = %236, %142
%148 = icmp sgt i32 %15, 1
br i1 %148, label %149, label %295
149: ; preds = %147
%150 = zext i32 %15 to i64
br label %239
151: ; preds = %144, %236
%152 = phi i32 [ %237, %236 ], [ 1, %144 ]
%153 = phi i32 [ %154, %236 ], [ %145, %144 ]
%154 = sdiv i32 %153, 2
%155 = sdiv i32 %153, 8
%156 = sitofp i32 %154 to double
%157 = fdiv double 0x401921FB54442D18, %156
%158 = icmp slt i32 %153, 8
br i1 %158, label %236, label %159
159: ; preds = %151
%160 = shl nsw i32 %154, 1
%161 = sext i32 %155 to i64
br label %162
162: ; preds = %159, %233
%163 = phi i32 [ 1, %159 ], [ %234, %233 ]
%164 = phi double [ 0.000000e+00, %159 ], [ %171, %233 ]
%165 = fmul double %164, 3.000000e+00
%166 = tail call double @cos(double %164)
%167 = tail call double @sin(double %164)
%168 = tail call double @cos(double %165)
%169 = tail call double @sin(double %165)
%170 = sitofp i32 %163 to double
%171 = fmul double %157, %170
%172 = icmp slt i32 %163, %15
br i1 %172, label %173, label %233
173: ; preds = %162
%174 = sub i32 %163, %154
br label %175
175: ; preds = %173, %228
%176 = phi i32 [ %163, %173 ], [ %230, %228 ]
%177 = phi i32 [ %160, %173 ], [ %231, %228 ]
%178 = icmp slt i32 %176, %15
br i1 %178, label %179, label %228
179: ; preds = %175
%180 = sext i32 %176 to i64
%181 = sext i32 %177 to i64
br label %182
182: ; preds = %179, %182
%183 = phi i64 [ %180, %179 ], [ %226, %182 ]
%184 = add nsw i64 %183, %161
%185 = add nsw i64 %184, %161
%186 = add nsw i64 %185, %161
%187 = getelementptr inbounds double, double* %4, i64 %183
%188 = load double, double* %187
%189 = getelementptr inbounds double, double* %4, i64 %185
%190 = load double, double* %189
%191 = fsub double %188, %190
%192 = fadd double %188, %190
store double %192, double* %187
%193 = getelementptr inbounds double, double* %4, i64 %184
%194 = load double, double* %193
%195 = getelementptr inbounds double, double* %4, i64 %186
%196 = load double, double* %195
%197 = fsub double %194, %196
%198 = fadd double %194, %196
store double %198, double* %193
%199 = getelementptr inbounds double, double* %5, i64 %183
%200 = load double, double* %199
%201 = getelementptr inbounds double, double* %5, i64 %185
%202 = load double, double* %201
%203 = fsub double %200, %202
%204 = fadd double %200, %202
store double %204, double* %199
%205 = getelementptr inbounds double, double* %5, i64 %184
%206 = load double, double* %205
%207 = getelementptr inbounds double, double* %5, i64 %186
%208 = load double, double* %207
%209 = fsub double %206, %208
%210 = fadd double %206, %208
store double %210, double* %205
%211 = fsub double %191, %209
%212 = fadd double %191, %209
%213 = fsub double %197, %203
%214 = fadd double %197, %203
%215 = fneg double %213
%216 = fmul double %167, %215
%217 = tail call double @llvm.fmuladd.f64(double %212, double %166, double %216)
store double %217, double* %189
%218 = fneg double %212
%219 = fmul double %167, %218
%220 = tail call double @llvm.fmuladd.f64(double %215, double %166, double %219)
store double %220, double* %201
%221 = fmul double %169, %214
%222 = tail call double @llvm.fmuladd.f64(double %211, double %168, double %221)
store double %222, double* %195
%223 = fneg double %211
%224 = fmul double %169, %223
%225 = tail call double @llvm.fmuladd.f64(double %214, double %168, double %224)
store double %225, double* %207
%226 = add i64 %183, %181
%227 = icmp slt i64 %226, %146
br i1 %227, label %182, label %228
228: ; preds = %182, %175
%229 = shl nsw i32 %177, 1
%230 = add i32 %174, %229
%231 = shl nsw i32 %177, 2
%232 = icmp slt i32 %230, %15
br i1 %232, label %175, label %233
233: ; preds = %228, %162
%234 = add nuw nsw i32 %163, 1
%235 = icmp eq i32 %163, %155
br i1 %235, label %236, label %162
236: ; preds = %233, %151
%237 = add nuw nsw i32 %152, 1
%238 = icmp eq i32 %237, %14
br i1 %238, label %147, label %151
239: ; preds = %149, %265
%240 = phi i32 [ %267, %265 ], [ 1, %149 ]
%241 = phi i32 [ %268, %265 ], [ 4, %149 ]
%242 = icmp sgt i32 %240, %15
br i1 %242, label %265, label %243
243: ; preds = %239
%244 = sext i32 %240 to i64
%245 = sext i32 %241 to i64
br label %249
246: ; preds = %265
br i1 %148, label %247, label %295
247: ; preds = %246
%248 = zext i32 %15 to i64
br label %270
249: ; preds = %243, %249
%250 = phi i64 [ %244, %243 ], [ %263, %249 ]
%251 = getelementptr inbounds double, double* %4, i64 %250
%252 = load double, double* %251
%253 = getelementptr inbounds double, double* %0, i64 %250
%254 = load double, double* %253
%255 = fadd double %252, %254
store double %255, double* %251
%256 = fsub double %252, %254
store double %256, double* %253
%257 = getelementptr inbounds double, double* %5, i64 %250
%258 = load double, double* %257
%259 = getelementptr inbounds double, double* %1, i64 %250
%260 = load double, double* %259
%261 = fadd double %258, %260
store double %261, double* %257
%262 = fsub double %258, %260
store double %262, double* %259
%263 = add i64 %250, %245
%264 = icmp sgt i64 %263, %150
br i1 %264, label %265, label %249
265: ; preds = %249, %239
%266 = shl nuw nsw i32 %241, 1
%267 = add nsw i32 %266, -1
%268 = shl nsw i32 %241, 2
%269 = icmp sgt i32 %266, %15
br i1 %269, label %246, label %239
270: ; preds = %247, %291
%271 = phi i64 [ 1, %247 ], [ %293, %291 ]
%272 = phi i32 [ 1, %247 ], [ %292, %291 ]
%273 = sext i32 %272 to i64
%274 = icmp slt i64 %271, %273
br i1 %274, label %275, label %284
275: ; preds = %270
%276 = getelementptr inbounds double, double* %4, i64 %273
%277 = load double, double* %276
%278 = getelementptr inbounds double, double* %4, i64 %271
%279 = load double, double* %278
store double %279, double* %276
store double %277, double* %278
%280 = getelementptr inbounds double, double* %5, i64 %273
%281 = load double, double* %280
%282 = getelementptr inbounds double, double* %5, i64 %271
%283 = load double, double* %282
store double %283, double* %280
store double %281, double* %282
br label %284
284: ; preds = %275, %270
br label %285
285: ; preds = %284, %285
%286 = phi i32 [ %288, %285 ], [ %15, %284 ]
%287 = phi i32 [ %290, %285 ], [ %272, %284 ]
%288 = sdiv i32 %286, 2
%289 = icmp sgt i32 %287, %288
%290 = sub nsw i32 %287, %288
br i1 %289, label %285, label %291
291: ; preds = %285
%292 = add nsw i32 %287, %288
%293 = add nuw nsw i64 %271, 1
%294 = icmp eq i64 %293, %248
br i1 %294, label %295, label %270
295: ; preds = %291, %147, %246
ret i32 %15
}