Re: [RFA] Fix bit/byte unit thinko in is_aliasing_offset

[Olivier Hainque <hainque at act-europe dot fr>]

Geoff Keating wrote:
> This is supposed to behave the same way in GNU C; so you should make
> the testcase into a proper dejagnu testcase (by using abort() or
> exit(0))...

 OK. A couple of questions, still. On at least x86-linux, the testcase adapted
 as below compiles fine and aborts with or without the suggested patch, and it
 appears the compiler does not even get into is_aligning_offset anyway. I also
 presume that the maximum supported value for ALIGNMENT depends on the target.

 How is this supposed to work in the compiler for C ?

 How should we ensure ALIGNMENT is large enough and still not too large on
 various targets ?

 Thanks in advance for your help,

 Olivier


     #define ALIGNMENT 32

     typedef int aligned_int __attribute__ ((aligned (ALIGNMENT)));

     int
     main (void)
     {
       aligned_int x;

       if (((unsigned long) &x % ALIGNMENT) != 0)
	 abort ();

       return 0;
     }