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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug tree-optimization/85315] missed range optimisation opportunity
 for derefences where index must be 0 or otherwise constrained
Date: Wed, 18 Nov 2020 15:17:04 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D85315

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #13 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Andrew Macleod from comment #12)
> Maybe I'm a little dense.
>=20
> if we are presuming that=20=20
>   &x + (a + b)=20
> implies a + b =3D=3D 0, then we also should assume that

&x + (a + b) for scalar x doesn't imply a + b =3D=3D 0, it implies a + b <=
=3D 1.
Only when it is dereferenced, i.e. (&x)[a + b] is accessed a + b has to be =
0.=