reproduce:
        # apt-get install sparse
        # sparse version: v0.6.4-39-gce1a6720-dirty
        git remote add drm-intel git://anongit.freedesktop.org/drm-intel
        git fetch --no-tags drm-intel drm-intel-gt-next
        git checkout 968853033d8aa4dbb80fbafa6f5d9b6a0ea21272
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=x86_64 olddefconfig
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/gpu/drm/i915/