PVS-Studio warning V571 for blender

static void fcurve_add_to_list (....)
{
  ...
  if (agrp == NULL) {
    if (agrp == NULL) {
  ...
}

This suspicious code was found in blender project by PVS-Studio static code analyzer.
Warning message is:
V571 Recurring check. The 'if (agrp == ((void *) 0))' condition was already verified in line 1108. bf_blenkernel ipo.c 1110

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/