Re: Defending GCC considered futile

[Florian Weimer <fw@deneb.enyo.de>]

* Stefan Monnier:

>> LLVM was first relased in 2003, Clang was opened up in 2007 (but is
>> likely a bit older).  Those aren't young projects by any standard, and
>> I doubt their sheets are particularly clean by this point.
>
> Compare that to the age of GCC, and while I agree it's had time to grow
> warts, it's still much cleaner than GCC and its structure is much better
> adapted to current compiler technology needs.

I have not worked on both compilers, so I'm not sure if that's
accurate.  Considering that the “clean sheets” claim has been around
for five years, I do have my doubts that this is still based on fact
(if it ever was).

One definite advantage for LLVM is that they target GCC 4.7 and later
as the bootstrap compiler (or more precisely, the C++11 subset also
supported by Microsoft Visual C++ 2012 and Clang 3.1).  That does
allow for some clean-ups, but of course, it concerns rather
superficial matters.

> GCC has also changed quite a bit during all those years, and not only by
> accruing "stuff" but also by internal redesigns, which helped it stay
> "on top of its game", but from the point of view of a someone wanting to
> add some new optimization/feature, the technical attractiveness of GCC
> is no match to LLVM.

It depends on what you want to do.  GCC's architecture has its
benefits because it allows the introduction of optimizations which
know more about front-end constructs than what can be made explicit in
its IR.