Re: [www] Document C++ -O0 improvements

[Paolo Bonzini <bonzini at gnu dot org>]

> +     <li>When compiling without optimizations (-O0), the C++ frontend is
> +         <strong>much</strong> faster than in any previous versions of GCC.
> +         Independent testers have measured speed-ups up to 25% in real-world
> +         production code, compared to the 3.4 family (which was already the
> +         fastest version to date). Upgrading from older versions might show
> +         even bigger improvements.</li>

What about C?  Some patches should have also given some improvements, 
though not as extreme (C++ had lexing upfront, precedence parsing, 
etc.).  For example

http://gcc.gnu.org/ml/gcc-patches/2004-10/msg02060.html (c_lex speedup)
http://gcc.gnu.org/ml/gcc-patches/2004-10/msg01879.html (edge vector)
http://gcc.gnu.org/ml/gcc-patches/2004-08/msg01318.html (share int_cst)
http://gcc.gnu.org/ml/gcc-patches/2004-06/msg01417.html (cfg expansion)

would apply to C as well.  The last one has mostly fixed the -O0 
regressions introduced by tree-ssa, but was an improvement anyway.

What about

<li>When compiling without optimizations (-O0), GCC will be faster than 
any previous version.  This is especially true for the C++ front-end, 
for which independent testers have measured speed-ups up to 25% in 
real-world production code, compared to the 3.4 family (which was 
<strong>already</strong> the fastest version to date). Upgrading from 
older versions might show even bigger improvements.</li>

Paolo