On Thursday, 27 March 2014 at 18:18:25 UTC, H. S. Teoh wrote:
Some time ago, Iain Buclaw kindly added non-asm implementations
of math
functions in std.math. However, CTFE still seems unable to
correctly
evaluate certain functions like atan2:
import std.math;
enum x = atan2(1.0, 2.0);
Compiler output:
/usr/src/d/phobos/std/math.d(856): Error: asm statements
cannot be interpreted at compile time
/usr/src/d/phobos/std/math.d(917): called from here:
atan2(cast(real)y, cast(real)x)
test.d(2): called from here: atan2(1.00000, 2.00000)
Looking at std/math.d, it appears that
version=InlineAsm_X86_Any is
defined, which leads to the asm implementation of atan2, which
CTFE
can't interpret.
However, right below that block is an else block containing a D
implementation of atan2 that AFAICT *can* be interpreted in
CTFE.
So it would appear that version=InlineAsm_X86_Any should be
suppressed
during CTFE? But I'm not sure how this could be done in the
compiler.
In any case, it's an annoying limitation. :-(
T
//----
auto atan(double x)
{
version(InlineAsm_X86_Any)
if (!__ctfe)
{
asm
{
...
}
return;
}
Fall back non-InlineAsm_X86_Any and ctfe
}
//----
?
