[Bug ipa/108695] [13 Regression] Wrong code since r13-5215-gb1f30bf42d8d47 for dd_rescue package

["jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108695

--- Comment #14 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Martin Liška from comment #10)
> > where the XOR16 is implemented as:
> > 
> > #define XORN(in1,in2,out,len)	\
> > do {				\
> > 	uint _i;		\
> > 	for (_i = 0; _i < len/sizeof(ulong); ++_i)	\
> > 		*((ulong*)(out)+_i) = *((ulong*)(in1)+_i) ^ *((ulong*)(in2)+_i);	\
> > } while(0)
> 
> I can confirm that changing that to:
> 
> #define XORN(in1, in2, out, len)                  \
> 	do                                            \
> 	{                                             \
> 		uint _i;                                  \
> 		for (_i = 0; _i < len; ++_i)              \
> 			*(out + _i) = *(in1 + _i) ^ *(in2 + _i); \
> 	} while (0)
> 
> fixes the problem. It seems very close to what I saw here:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83201#c13

It depends on if those arrays were stored as ulong or will be later read as
ulong or something else.
One could also use typedef ulong ulong_alias __attribute__((may_alias));
and use ulong_alias* above, or memcpy to/out of ulong temporaries.