Basic benchmark

[Andrei Alexandrescu]

Jarrett Billingsley wrote:
> On Sat, Dec 13, 2008 at 11:16 AM, Tomas Lindquist Olsen
> <tomas at famolsen.dk> wrote:
>> I tried this out with Tango + DMD 1.033, Tango + LDC r847 and GCC 4.3.2, my
>> timings are as follows, best of three:
>>
>> $ dmd bench.d -O -release -inline
>> long arith:  55630 ms
>> nested loop:  5090 ms
>>
>>
>> $ ldc bench.d -O3 -release -inline
>> long arith:  13870 ms
>> nested loop:   120 ms
>>
>>
>> $ gcc bench.c -O3 -s -fomit-frame-pointer
>> long arith: 13600 ms
>> nested loop:  170 ms
>>
>>
>> My cpu is: Athlon64 X2 3800+
>>
> 
> Go LDC!
> 
> I hope bearophile will eventually understand that DMD is not good at
> optimizing code, and so comparing its output to GCC's is ultimately
> meaningless.

I must have missed the memo. How is dmd not good at optimizing code? 
Without knowing many details about it, my understanding is that dmd 
performs common optimization reasonably well and that this particular 
problem has to do with the long division routine.

Andrei