opCmp / opEquals do not actually support partial orders

[Ivan Kazmenko]

On Wednesday, 18 July 2018 at 14:02:28 UTC, Dominikus Dittes 
Scherkl wrote:
> On Wednesday, 18 July 2018 at 13:12:05 UTC, Ivan Kazmenko wrote:
>> Leaving x uninitialized, or using floats, work about the same.
> No, floats are a whole lot less slow.

Are they?  Locally, I don't see much difference.  Code:

-----
import std.datetime.stopwatch, std.math, std.stdio;
immutable float limit = 10 ^^ 7;
void main () {
     int s;
     auto sw = StopWatch (AutoStart.yes);
     auto start = sw.peek ();
     for (float x = NaN (0), i = 0; i < limit; i++)
         s += (i < x);
     auto now = sw.peek ();
     writeln (now - start, ", sum is ", s);
}
-----

Result:

-----
1 sec, 467 ms, 40 μs, and 6 hnsecs, sum is 0
-----

Fluctuating within a few per cent, but very similar to version 
with doubles.

That's by DMD32 on Windows.  (Sorry, my DMD64 broke after 
upgrading Visual Studio to 2017, and I failed to fix it right 
now.  Anyway, it's not like x86_64 uses a different set of 
general purpose floating-point hardware, right?)

Ivan Kazmenko.