On Mon, Sep 12, 2022 at 1:23 PM Fredrik Hederstierna via Gcc
<gcc@gcc.gnu.org> wrote:
>
> Hi,
>
> We have a function that does not used an in-parameter, simplified example:
>
> void test_unused_string_param_gc(const char* unused)
> {
> // empty
> }
>
> Though when we have calls to this function, the arguments are still put in
> the memory, causing unnecessary flash memory usage for 'dead parameters'.
>
> Example if having a call (from another file) as
>
> test_unused_string_param_gc("This string is not garbage-collected?");
>
> Then this string will still be added to our finally build binary?
>
> We compile with -Os, and have tried different flags to try get rid of this
> dead parameter data,
> do anyone know if this is the expected behavior and why? Or if we are missing
> any optimization flags, like LTO etc?
Without LTO there is no way the unused parameter can be elided on the
caller side so yes, try enabling LTO.
Richard.
> Best Regards,
> Fredrik
>
