[Bug middle-end/66031] Spurious array bounds warning

[slash.tmp at free dot fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66031

Mason <slash.tmp at free dot fr> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |slash.tmp at free dot fr

--- Comment #2 from Mason <slash.tmp at free dot fr> ---
FWIW, the following code looks somewhat fishy to me:

unsigned char f = 10;
extern unsigned char p[1];
char check(unsigned int n)
{
   if (n - 1 >= f) return p[n];
   return 1;
}

p[n] is well-defined iff n = 0

If n = 0, n - 1 = UINT_MAX, thus the test is true for any f
No other value of n is allowed as an index into p.

Thus I would expect gcc to turn the code into

  return (n == 0) ? p[0] : 1;