Re: [Patch, testsuite] Skip addr_equal-1 if target keeps null pointer checks

[Jeff Law <law@redhat.com>]

On 09/28/2015 02:15 AM, Senthil Kumar Selvaraj wrote:
> Hi,
>
>    The below patch skips gcc.dg/addr_equal-1.c if the target keeps null
>    pointer checks.
>
>    The test fails for such targets (avr, in my case) because the address
>    comparison in the below code does not resolve to a constant, causing
>    builtin_constant_p to return false and fail the test.
>
>    /* Variables and functions do not share same memory locations otherwise.  */
>    if (!__builtin_constant_p ((void *)undef_fn0 == (void *)&undef_var0))
>      abort ();
>
>    For targets that delete null pointer checks, the equality comparison expression
>    is optimized away to 0, as the code in match.pd knows they can only be
>    equal if they are both NULL, which cannot be true since
>    flag-delete-null-pointer-checks is on.
>
>    For targets that keep null pointer checks, 0 is a valid address and the
> 	comparison expression is left as is, and that causes a later pass to
> 	fold the builtin_constant_p to a false value, resulting in the test failure.
This sounds like a failing in the compiler itself, not a testsuite issue.

Even on a target where objects can be at address 0, you can't have a 
variable and a function at the same address.

Jeff