On Sunday, 3 July 2016 at 11:49:15 UTC, Andrei Alexandrescu wrote:
Well to be more precise here's what I'm looking for. When you
compare an integral with a floating point number, the integral
is first converted to floating point format. I.e. for long x
and double y, x == y is the same as double(x) == y.
Now, say we want to eliminate the "bad" cases of this
comparison. Those would make it non-transitive. Consider two
distinct longs x1 and x2. If they convert to the same double y,
then x1 == y and x2 == y are true, which is contradictory with
x1 != x2.
If you assume round-to-even rounding mode then you get unique
representations for integers in the ranges as other people have
suggested:
int_to_float : [-((1<<24)-1) , (1<<24)-1]
int_to_double : [-((1<<53)-1) , (1<<53)-1]
