[dmd-internals] 3rd Biweekly Sprint Planning

[Walter Bright via dmd-internals]

On 8/11/2015 6:24 AM, Martin Nowak via dmd-internals wrote:
> Please don't underestimate the problem. If we release a self-hosted compiler 
> that is 30% slower, then the message between the lines is that's b/c of D is 
> slower than C++.

30% is a problem, but not a disaster. Some mitigating factors:

1. I believe that there is an excessive number of template instantiations going 
on. This is borne out by the profile results you supplied (thank you). I.e. it 
should not be necessary to instantiate a template in order to determine if it 
has already been instantiated.

2. Not much effort has been expended in profiling dmd in a while. I suspect 
there is more unrecognized low hanging fruit to speed it up.

3. dmd for Windows is compiled by the same backend as dmd has, so there 
shouldn't be a speed difference there.

4. I want to unwind the changes that resulted in the large dmd slowdowns that 
recently appeared and find other ways.

5. Having the source code in D offers possibilities for optimization that are 
not so practical in C++ source.