integral to floating point conversion

[Walter Bright via Digitalmars-d]

On 7/2/2016 1:17 PM, Andrei Alexandrescu wrote:
> So what's the fastest way to figure that an integral is convertible to a
> floating point value precisely (i.e. no other integral converts to the same
> floating point value)? Thanks! -- Andrei

Test that its absolute value is <= the largest unsigned value represented by the 
float's mantissa bits.