Hi,
My recent commit to emit asm name with -fdump-statistics-asmname
caused following ICE
for attached fortran test case.

during IPA pass: icf
power.fppized.f90:6:26:

    6 | END SUBROUTINE power_print
      |                          ^
internal compiler error: Segmentation fault
0xfddc13 crash_signal
        ../../gcc/gcc/toplev.cc:322
0x7f6f940de51f ???
        ./signal/../sysdeps/unix/sysv/linux/x86_64/libc_sigaction.c:0
0xfc909d get_function_name
        ../../gcc/gcc/statistics.cc:124
0xfc929f statistics_fini_pass_2(statistics_counter**, void*)
        ../../gcc/gcc/statistics.cc:175
0xfc94a4 void hash_table<stats_counter_hasher, false,
xcallocator>::traverse_noresize<void*,
&(statistics_fini_pass_2(statistics_counter**, void*))>(void*)
        ../../gcc/gcc/hash-table.h:1084
0xfc94a4 statistics_fini_pass()
        ../../gcc/gcc/statistics.cc:219
0xef12bc execute_todo
        ../../gcc/gcc/passes.cc:2142

This happens because fn was passed NULL in get_function_name.
The patch adds a check to see if fn is NULL before checking for
DECL_ASSEMBLER_NAME_SET_P, which fixes the issue.
In case the fn is NULL, it calls function_name(NULL) as per old behavior,
which returns "(nofn)".

Bootstrap+tested on x86_64-linux-gnu.
OK to commit ?

Thanks,
Prathamesh