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From: "acoplan 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 11:27:54 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D110791

--- Comment #2 from Alex Coplan <acoplan at gcc dot gnu.org> ---
(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:

In this case, with the input given in main, I think p should end up pointin=
g 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).=