narrowed down the problem area

[downs]

Tim Burrell wrote:
> downs wrote:
>>> Strangely, Vec v = void; Vec.sub(center, ray.orig, v); runs in 8.8s, producing a correct output once the printf at the bottom has been fixed,
>>> but Vec v = center - ray.orig; runs in 11.1s.
>> For some reason, the bad case, although inlined, stores its values back into memory. The fast case keeps working with them.
>>
>> So it comes down to a GDC FP "bug". I think changing to 4.2 or 4.3 might help. Does anybody have an up-to-date version of the 4.2.x patch?
> 
> Hey good deal on figuring this out!  It's good to know, especially for
> those of us using D for real-time simulation type stuff.
> 
> Is there really a GDC that compiles against gcc >= 4.2?!

I'm not sure; I remember somebody saying he'd managed to build it. And there's a post on d.gnu from somebody saying he'd gotten it to work, although he couldn't build phobos.

Since GDC seems to be .. inert at the moment, it'd probably up to some volunteer effort to upgrade it to 4.[23]. That, or get llvmdc up to speed.

Myself of course is mostly clueless about both compilers. :/

 --downs