On Thursday, 15 May 2014 at 13:01:34 UTC, Ola Fosheim Grøstad
wrote:
On Thursday, 15 May 2014 at 12:34:49 UTC, Dicebot wrote:
I think it is your turn to make a counter-example ;)
I've given 2 examples that no compiler can get at… because they
lack contextual knowledge. ;)
If compiler lacks contextual knowledge, than only means that
range is not actually semantically equivalent to a loop. Which is
quite possible if you start considering something like SIMD, this
is true.
What is wrong is assumption that such kinds of loops are anything
but tiny minority and this warrants generic "ranges can never be
as fast as loops" statement.
Btw,
Floating point math is inaccurate, that means the compiler
will have to guess what kind of accuracy you are happy with…
AFAIK it is actually not true. Floating point standard defines
basic precision guarantees and compilers are free to make any
adjustments outside of those basics. In your example you need to
verify generated assembly anyway, loop or range.
