c - How restrictive is the restrict keyword? -

i have following simple function

static inline void minvec(const double *restrict v, double *restrict vmin, unsigned length){   (unsigned = 0; < length; ++i)     vmin[i] = -v[i];   return; } 

which compiles , runs fine when use way

double v[] = {1, 2, 3}; minvec(v, v, 3); 

i've been led believe using restrict in case informs compiler each iteration of loop independent of others, loop can aggressively optimized. correct way of doing or poking implementation-defined behaviour here?

the restrict keyword purely optimization hint: allows compiler reorder reads/writes from/to restricted pointers other memory accesses. cannot done if compiler cannot prove memory behind pointer can accessed via pointer.

so, if restrict, tell compiler: "i assure pointer 1 points memory, please feel free reorder. aware blue elephants may appear if wrong, i'm human, can't wrong, bow before me."

this keyword sake of compiler, not sake!