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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/107533] Inefficient code sequence for fp16 testcase on
 aarch64
Date: Fri, 19 May 2023 04:12:55 +0000
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X-Bugzilla-Version: 13.0
X-Bugzilla-Keywords: missed-optimization
X-Bugzilla-Severity: enhancement
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D107533

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2023-05-19
     Ever confirmed|0                           |1
           Severity|normal                      |enhancement
             Status|UNCONFIRMED                 |NEW

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Take:
```
struct phalf {
    __fp16 first;
    __fp16 second;
};

void phalf_copy_(struct phalf *d, struct phalf src) {
    *d =3D src;
}
struct phalf phalf_copy0( __fp16 f, __fp16 s) {
    struct phalf t =3D {f, s};
    return t;
}
struct phalf phalf_copy(struct phalf* src) {
    return *src;
}
struct phalf phalf_copy1(__fp16 *f, __fp16 *s) {
    struct phalf t =3D {*f, *s};
    return t;
}
void phalf_copy2(struct phalf *d, __fp16 *f, __fp16 *s) {
    struct phalf t =3D {*f, *s};
    *d =3D t;
}
void phalf_copy3(struct phalf *d, struct phalf* src) {
    *d =3D *src;
}
void phalf_copy4(struct phalf *d, __fp16 f, __fp16 s) {
    struct phalf t =3D {f, s};
    *d =3D t;
}
```
2,3,4 are all ok, while 0, none, _ and 1 are bad.
Which points to return values and argument passing being bad (which we alre=
ady
knew had issues).

Confirmed.=