[Issue 19732] make std.complex.expi fast.

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=19732

--- Comment #4 from Bastiaan Veelo <Bastiaan at Veelo.net> ---
(In reply to kinke from comment #3)
> (In reply to Bastiaan Veelo from comment #2)
> > Nowadays, the x87 instruction fsincos is slower, not faster, than computing
> > sin and cos separately.
> > 
> > https://stackoverflow.com/questions/12485190/calling-fsincos-instruction-in-
> > llvm-slower-than-calling-libc-sin-cos-functions
> 
> Have you actually tested this on your box? I recently came to completely
> different results with LDC on my i5-3550:
> https://github.com/ldc-developers/ldc/pull/2855#issuecomment-491560143
> 
> Note that `long double` is extremely rare in C(++), but ubiquitous in D.

No I have not. What I'd like to know is why fsincos was removed from
std.complex.expi in 2012, and why it wasn't readed when std.math.expi was
deprecated last year.

Feel free to reopen, as you have done the test.

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