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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug rtl-optimization/101617] a ? -1 : 1 -> (-(type)a) | 1
Date: Mon, 26 Jul 2021 00:28:38 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D101617

--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
A few more canonicalization issues that need to be thought of:

"a >>u (bitsize-1)" and "a <s 0"
"a >>s (bitsize-1)" and "-(a <s 0)"

(In reply to Andrew Pinski from comment #6)
> Thinking about this some more, there is a canonicalization issue. We need=
 to
> decide if we want to canonicalization to just a ? -1 : 1; or expand it ou=
t.
> a ? 1 : 0 makes sense to do (cast) a;  So does "a ? 0 : 1".
>=20
> Does the current a ? -1 : 0 make sense or just add that to ifcvt.

PR101339 is related to that canonicalization really.

There are others.

Even things like:
(a =3D=3D 0) + 2
Should that be:
a =3D=3D 0 ? 3 : 2
On the gimple level
and then do the correct thing on the RTL level?=