LLVM IR influence on compiler debugging

[Timon Gehr]

On 07/08/2012 01:28 AM, Adam Wilson wrote:
> On Sat, 07 Jul 2012 16:15:11 -0700, Walter Bright
> <newshound2 at digitalmars.com> wrote:
>
>> On 7/7/2012 4:08 PM, Adam Wilson wrote:
>>> On Sat, 07 Jul 2012 11:48:44 -0700, Walter Bright
>>> <newshound2 at digitalmars.com>
>>> wrote:
>>>
>>>> On 7/7/2012 8:38 AM, Alex Rønne Petersen wrote:
>>>>> On a high-end 4-core x86, building LLVM and LDC can usually be
>>>>> done in less than an hour, even when building them in optimized mode.
>>>>
>>>> Building dmd on my Windows box takes 26 seconds, optimized, using a
>>>> single core.
>>>
>>> Build speed of the compiler itself is an utterly trivial matter, my
>>> primary
>>> concern is speed for the end-user. Even the build speed/memory usage
>>> of my
>>> projects is not a problem, I can always throw more money at hardware.
>>> For
>>> example, I am considering making the next round of developer box
>>> updates to
>>> Intel Xeon E1650's with 32GB RAM.
>>>
>>> Gentlemen, from a business prospective, compiler and/or project build
>>> times are
>>> the least of your problems. How well the code performs and most
>>> importantly the
>>> accuracy of the code generation is of key concern.
>>
>> Throwing more hardware at a problem isn't going to get you a 120x
>> increase in speed.
>
> I wont argue that, but again, that's not a primary concern. :-)
>
>> While you're right that the customer cares not how long it takes to
>> build the compiler, the speed is important for the edit-compile-debug
>> loop of developing the compiler. For me, it matters quite a bit.
>
> I imagine that it does, and honestly, I am not terribly concerned if DMD
> stays with it's current backend because once LLVM gets SEH, im gone. But
> I do wonder if DMD will become increasingly irrelevant as backends like
> GCC and LLVM advance. And I am particularly troubled by what seems like
> a duplication of effort in the face of more widely tested backends...
>

The DMD backend is very fast in comparison to other backends.

LLVM is unlikely to catch up in speed, because it is well architectured
and more general.

> All that said, I understand the legal predicament. You can't do anything
> about it and I'm not trying to convince you too. I just want to see more
> promotion and support of the other options available.
>