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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/113372] wrong code with _BitInt() arithmetics
 at -O1
Date: Mon, 15 Jan 2024 14:58:58 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D113372

--- Comment #17 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #15)
> (In reply to Jakub Jelinek from comment #14)
> > Created attachment 57085 [details]
> > gcc14-pr113372.patch
> >=20
> > The non-propagation workaround which seems to fix^H^H^Hworkaround all t=
hose
> > 4 issues (PR90348 testcase actually doesn't FAIL anymore, but I've veri=
fied
> > the patch results in in and buf no longer being shared) can look like t=
his.
>=20
> +	  || (INTEGRAL_TYPE_P (TREE_TYPE (use))
> +	      && TYPE_PRECISION (TREE_TYPE (use)) =3D=3D POINTER_SIZE)))
>=20
> ptrofftype_p (TREE_TYPE (use))

Aren't there targets where pointers are larger than sizetype?
I thought msp430, but that one uses __int20.

> I think it should be enough to look at gimple_assing_rhs1, that works
> for single non-invariant &a[i], for conversions and for offsetting of
> an invariant address (pointer-plus).

Is the invariant operand guaranteed to go first?  If it is pointer, guess
POINTER_PLUS_EXPR enforces that, and for sizetype addition guess an operand
can't be ADDR_EXPR, there would need to be a cast in a separate stmt.  So
perhaps ok.

As for Micha's fears, I can certainly try to dump statistics during
bootstrap/regtest on how many variables were shared and/or their cumulative
size without/with the patch and see if it has significant effects on real-w=
orld
code.=