"poll called with fds buffer too small" with link time optimization (-flto) - c

Question

Suddenly started getting this error at link time on some older code. I managed to replicate the problem with a very simple snippet of code:
#include <poll.h>
#include <stdio.h>
typedef struct
{
struct pollfd m_fds[6000];
nfds_t m_count;
} PollWrapper;
static PollWrapper g_pollWrapper;
int main()
{
return poll(g_pollWrapper.m_fds, g_pollWrapper.m_count, 0);
}
Compiling without -flto is fine.
gcc -Wall -O3 -o poll.exe poll.c # gcc 4.8.1-10ubuntu9
# successful
But adding -flto causes an error when linking:
gcc -Wall -O3 -flto -o poll.exe poll.c # gcc 4.8.1-10ubuntu9
# error
gcc -Wall -O3 -flto -o poll.o -o poll.c
# compilation is fine
gcc -Wall -O3 -flto -o poll.exe poll.o
# linking fails
/usr/include/x86_64-linux-gnu/bits/poll2.h: In function `main`:
/usr/include/x86_64-linux-gnu/bits/poll2.h:41:2: warning: call to `__poll_chk_warn` > declared with attribute warning: poll called with fds buffer too small file nfds entries [enabled by default]
return __poll_chk (__fds, __nfds, __timeout, __bos (__fds));
^
Having read related questions, I tried explicitly enabling and disabling the linker plugin, neither had any effect.
This only appears to happen with an array, none of the following have the same problem:
struct pollfd f;
int numfds = poll(&f, g_pollWrapper.m_size, duration);
or
struct pollfd fds[6000];
int numfds = poll(&f, g_pollWrapper.m_size, duration);
etc.
Am I either missing something obvious or is this an LTO defect in my GCC, and if so is there a way I can work around it?