DMD backend quality (Was: Re: DIP 1031--Deprecate Brace-Style Struct Initializers--Community Review Round 1 Discussion)

[bachmeier]

On Tuesday, 18 February 2020 at 15:30:57 UTC, jxel wrote:
> On Tuesday, 18 February 2020 at 13:04:36 UTC, Dejan Lekic wrote:
>> On Sunday, 16 February 2020 at 00:16:24 UTC, H. S. Teoh wrote:
>>> ...
>>> Of course, DMD is still very fast at compiling and useful for 
>>> smaller utilities and script-like programs where performance 
>>> isn't critical, or for running unittests for isolated modules 
>>> during development due to fast turnaround times. But codegen 
>>> quality is definitely not among the reasons I still use DMD.
>>> ...
>>
>> I do not know about others, but I personally do not expect DMD 
>> to be as performant as people would like it to be. As a 
>> REFERENCE COMPILER I expect it to be as close to the current 
>> language specification as possible. DMD does that beautifully, 
>> and on top of that does a pretty good job at compiling code 
>> quite fast. I can't ask for more! - If they optimize the 
>> codegen to generate better code, that is fine, but not 
>> essential, as I use GCC (others may prefer LDC) for release 
>> builds.
>
> The problem is that efforts are divided as a result. Work still 
> has to be maintained on the backend. As someone showed there's 
> multiple PR that have stagnated because no one is willing to 
> look at them that modify the backend to comply with the C ABI. 
> Bugs that have been open for years. Bugs that don't exist in 
> LDC, even though that's basically being maintained by one 
> person. If people want a fast backend, you can build a custom 
> backend for performance in LLVM, a few projects have done this 
> already. But honestly that's a waste of time. The slowest part 
> of D is the frontend and CTFE not the backend in LDC. That's 
> not even mentioning the constant out of memory problems I 
> experience and have to try to optimize the compiler for with my 
> code.

DMD already exists, nobody's forced to use it, and I doubt it's 
sucking any resources away from LDC.