gcc: conjf suboptimal

Don't know what's going on here:

``` c
// myconjf.c
// epiphany-elf-gcc -O3 -ffast-math -c
#include <complex.h>
float complex myconjf(float complex n)
{
        return conjf(n);
}
```

What I get

``` asm
myconjf:
mov r2,0x0
movt r2,0x8000
eor r2,r2,r1
mov r3,r0
mov r0,r3
mov r1,r2
rts
```

What I want

``` asm
myconjf:
mov r2,0x0
movt r2,0x8000
eor r1,r2,r1
rts
```
