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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/114704] Missed optimization : eliminate store
 if the value is known in all predecessors
Date: Fri, 12 Apr 2024 22:39:38 +0000
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X-Bugzilla-Product: gcc
X-Bugzilla-Component: tree-optimization
X-Bugzilla-Version: 14.0
X-Bugzilla-Keywords: missed-optimization
X-Bugzilla-Severity: enhancement
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D114704

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2024-04-12
             Status|UNCONFIRMED                 |NEW

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed. A more general testcase:
```
void dummy();

void src(int *p, int a){
    int t =3D *p;
    if(t =3D=3D a)
        goto then;
    else {
        dummy();
        t =3D *p;
        if(t =3D=3D a)
            goto then;
        else
            return;
    }

then:
    *p =3D t; // *p is already a, it's dead now
}

```=