Hello,
On Mon, Oct 02 2023, Hanke Zhang via Gcc wrote:
> Hi, I have some questions about the strategy and behavior of function
> splitting in gcc, like the following code:
>
> int glob;
> void f() {
> if (glob) {
> printf("short path\n");
> return;
> }
> // do lots of expensive things
> // ...
> }
>
> I hope it can be broken down like below, so that the whole function
> can perhaps be inlined, which is more efficient.
>
> int glob;
> void f() {
> if (glob) {
> printf("short path\n");
> return;
> }
> f_part();
> }
>
> void f_part() {
> // do lots of expensive things
> // ...
> }
>
>
> But on the contrary, gcc splits it like these, which not only does not
> bring any benefits, but may increase the time consumption, because the
> function call itself is a more resource-intensive thing.
>
> int glob;
> void f() {
> if (glob) {
> f_part();
> return;
> }
> // do lots of expensive things
> // ...
> }
>
> void f_part() {
> printf("short path\n"); // just do this????
> }
>
> Are there any options I can offer to gcc to change this behavior? Or
> do I need to make some changes in ipa-split.cc?
I'd suggest you file a bug to Bugzilla with a specific example that is
mis-handled, then we can have a look and discuss what and why happens
and what can be done about it.
Thanks,
Martin
