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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/111730] erroneous alloc-size-larger-than
 warning with -O1
Date: Mon, 09 Oct 2023 02:15:42 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D111730

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note you can reproduce the same warning with ( -O2 -fno-code-hoisting
-fno-tree-loop-im -fno-tree-pre):
```
// #include <stdlib.h>

typedef long unsigned int size_t;
extern void *malloc (size_t size) __attribute__ ((__malloc__));
int *t;
void foo(int x) {
    // if (x < 1) return;
    for (int i =3D 0; i < x; i++) {*t =3D i;}

    char *a =3D malloc(x);

    for (int i =3D 0; i < x; i++)
        a[i] =3D 0;

    while (a[x - 1]) {*t++;}
}
```

I still think you should add a check for x being negative to fix the
code/warning. Unless you have a unreduced testcase which has the test before
and still able to produce the warning, this will most likely be closed as
invalid.=