On Saturday, 31 May 2014 at 23:30:41 UTC, Walter Bright wrote:
There isn't a suitable place. To make it work, data flow
analysis would have to be added to the front end. While doable,
this is not a simple addition. Eventually, we'll have to do it
as a lot of things become possible & better with data flow
analysis, not just bounds check elimination.
I've always wondered if VRP can be leveraged in certain
situations. I can't remember exactly how it's supposed to work,
but very basically, isn't it just numeric variables (and
expressions?) having an associated range that they carry around
with them at compile time, so something like this is possible:
long n1 = long.max;
int n2 = n1 % 3; //No cast needed due to VRP
Couldn't this be used for other things as well, such as detecting
numeric overflow at compile time, or like Nordlow suggested,
figuring out when it's safe to elide an array bounds check?
