Why DMD is so slow?

Dave Dave_member at pathlink.com
Tue Jun 3 17:49:33 PDT 2008

"Saaa" <empty at needmail.com> wrote in message 
news:g240q6$14cm$1 at digitalmars.com...
>I meant GDC :/
> The original post reports a more than one minute runtime using DMD,
> I can't replicate that (with a reasonable cpu).
> Or did I miss something ..

I think you're on to something.

I get wildly different timings over several runs, and sometimes get a (much) 
faster time _without_ the -O switch on a P4.

No way should that code be that much slower between DMD and GDC... It's a 
bug. It's probably an alignment issue, but I wouldn't be surprised to see 
incorrect results for DMD either.

The OP should post that code and the results as a bug. C++ code with DMC 
probably wouldn't reproduce it because the D version is using the built-in 
complex type, which is probably the heart of the bug.


- Dave

>> I'm sure DMC is no faster than DMD here - the problem is the backend 
>> optimizer.  Many benchmarks (especially concerning floating point) have 
>> shown this.
>> -[Unknown]
>> Saaa wrote:
>>> Did anybody verify DMC being faster?
>>> I don't have DMC, but my DMD code ran in 2.6s iso more than a minute.
>>>> As everyone has said, these are problems in DMD and DMC.

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