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From: "xry111 at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/110791] [12/13/14 Regression] arm: Wrong code
 with -Os -march=armv8.1-m.main
Date: Mon, 24 Jul 2023 11:29:47 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D110791

Xi Ruoyao <xry111 at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |UNCONFIRMED
     Ever confirmed|1                           |0

--- Comment #3 from Xi Ruoyao <xry111 at gcc dot gnu.org> ---
(In reply to Alex Coplan from comment #2)
> (In reply to Xi Ruoyao from comment #1)
> > Isn't this a UB?
> >=20
> >   while (p >=3D path && *p !=3D '/')
> >     p--;
> >=20
> > This will cause p to become "&main::path[0] - 1".  C23 6.5.6p9:
>=20
> In this case, with the input given in main, I think p should end up point=
ing
> to main::path + 1 (since we pass in main::path + 2, and foo can only ever
> decrement p at most one below its parameter path).

Sorry, I misread the code.  I guess I need to drink some coffee now...=