undefined | Better HN

0 pointsalkh1y ago0 comments

I thought you could simply add `restrict`[1] to indicate that only one pointer points to a specific object? Shouldn't this help?

[1]https://en.cppreference.com/w/c/language/restrict

0 comments

aidenn01y ago

You can add that qualifier, but nothing will enforce that objects don't overlap. So you replaced slow correct code with fast incorrect code.

TheNewAndy1y ago

If you believed the pointers didn't alias and they actually did then you replaced slow incorrect code with fast incorrect code

aidenn01y ago

That doesn't follow? If you replaced every call of memcpy with memmove (to use an example from the standard library), then your program is no less correct than it was before (and possibly more). The converse is that adding "restrict" qualifiers to existing functions can only make your program less correct, not more.

1 more reply

j / k navigate · click thread line to collapse

0 pointsalkh1y ago0 comments

I thought you could simply add `restrict`[1] to indicate that only one pointer points to a specific object? Shouldn't this help?

[1]https://en.cppreference.com/w/c/language/restrict

0 comments

aidenn01y ago

You can add that qualifier, but nothing will enforce that objects don't overlap. So you replaced slow correct code with fast incorrect code.

TheNewAndy1y ago

If you believed the pointers didn't alias and they actually did then you replaced slow incorrect code with fast incorrect code

aidenn01y ago

1 more reply

j / k navigate · click thread line to collapse