Re: Computer architects leaving Intel...

Josh Vanderhoof <x@y.z> writes:

[how to write a portable, UB-free check if mempcy() intervals overlap]

It is legal to test for equality between pointers to different objects

Right.  This observation is the key insight.

so you could test for overlap by testing against every element in the
array.

For a complete test, compare the address of every element in both
arrays.  For example:

   #include <stddef.h>

   _Bool
   memcpy_intervals_overlap( void *const vd, void *const vs, size_t n ){
     char    *d = vd,  *s = vs;
     size_t   k = 0;

       while(  k < n  &&  d != vs  &&  s != vd  )  k++,  d++,  s++;

       return  k < n;
   }