C6000 - Optimizer eliminates assignment to volatile subobject

#include <stdlib.h>

_Pragma("FUNC_CANNOT_INLINE") void test_device()
{
    struct device {
        volatile unsigned tcc;
    } dev;

    unsigned tcc = rand();

    dev.tcc = tcc;
}

I expected this code to generate a store to dev.tcc, but that was not the case. The generated code looks like this:

	.sect	".text"
	.clink
	.global	_Z11test_devicev
_Z11test_devicev:
           CALLRET .S1     rand              ; 
           NOP             5
$C$RL582:  ; CALL-RETURN OCCURS {rand} 0     ; 

The compiler version I used is 7.4.13. The compiler flags are the following:

-mv6600 --abi=eabi -O3 --symdebug:none --optimize_with_debug=off --program_level_compile --gcc --no_bad_aliases --speculate_loads=auto --remove_hooks_when_inlining --opt_for_speed=5 --gen_opt_info=2 --call_assumptions=0 -k

I do get a warning about dev being set but not used, which is misleading as dev is not being set, but dev.tcc is, and assigning to dev.tcc is observable behavior according to the C++ standard.