On Monday, 16 May 2016 at 04:02:54 UTC, Manu wrote:
extended x = 1.3;
x + y;
If that code were to CTFE, I expect the CTFE to use extended
precision.
My point is, CTFE should surely follow the types and language
semantics as if it were runtime generated code... It's not
reasonable
that CTFE has higher precision applied than the same code at
runtime.
CTFE must give the exact same result as runtime execution of
the function.
You are not even guaranteed to get the same result on two
different x86 implementations. AMD64:
"The processor produces a floating-point result defined by the
IEEE standard to be infinitely precise.
This result may not be representable exactly in the destination
format, because only a subset of the
continuum of real numbers finds exact representation in any
particular floating-point format."
