[Bug rtl-optimization/110791] [12/13/14 Regression] arm: Wrong code with -Os -march=armv8.1-m.main

[xry111 at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110791

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
                 CC|                            |xry111 at gcc dot gnu.org
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2023-07-24

--- Comment #1 from Xi Ruoyao <xry111 at gcc dot gnu.org> ---
Isn't this a UB?

  while (p >= path && *p != '/')
    p--;

This will cause p to become "&main::path[0] - 1".  C23 6.5.6p9:

If the pointer operand and the result do not point to elements of the same
array object or one past the last element of the array object, the behavior is
undefined.