[Bug middle-end/42909] inefficient code for trivial tail-call with large struct parameter

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42909

--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #5)
> Created attachment 61618 [details]
> Patch which I am testing for the aarch64 issue

But it miscompiles (there is no testcase for this though):
```
struct s1 { int x[1024]; };

void f(struct s1, struct s1);

void g(struct s1 x)
{
    f(x, x);
}
```
Where we need a copy of the incoming argument as we can only reuse it once.

Let me think of how to fix that.