incorrect warning 'auto' variable 'a' may be used before in

This example:

static int
f (void)
{
int a = 0;
if (a > 0)
{
return a;
}

return 0;
}

produces incorrect warning:
t.c:7: warning 84: 'auto' variable 'a' may be used before initialization
t.c:7: warning 126: unreachable code

SDCC version:
SDCC : mcs51/gbz80/z80/ds390/pic16/pic14/TININative/ds400/hc08 2.9.7 #5646 (Jan 23 2010) (UNIX)

Borut