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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/105523] Wrong warning array subscript [0] is outside
 array bounds
Date: Tue, 25 Apr 2023 16:30:29 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D105523

--- Comment #24 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to LIU Hao from comment #22)
> Yes, GCC should be told to shut up about dereferencing artificial address
> values.

NO.
Take:
```
static inline int f(int *a)
{
  return a[10];
}

int g()
{
  return f(0);
}
```
The warning is there for the above case really (and similar ones with struct
offsets). Where you originally have a null pointer and have an offset from
there; by the time the warning happens, the IR does not know if it was
originally from an offset of a null pointer or if the value was written in.=
 The
paramater is there to "tune" the heurstic to figure out if it is null point=
er
deference or if it is some real (HW) address. Maybe
-fno-delete-null-pointer-checks should imply --param=3Dmin-pagesize=3D0, th=
ough
some folks want the warning indepdent of trying to delete null pointer chec=
ks.=