Re: gcc versus g++ optimization of identical C code

[Andrew Haley <aph@xxxxxxxxxx>]

Hi,

On 07/23/2012 04:04 PM, Jules Colding wrote:

> I've observed that my little side project: 
> 
> https://github.com/colding/disruptorC
> 
> 
> consistently performs approximately 10% better when compiled with
> g++ instead of gcc. Just adding "CC=g++" to configure.ac just after
> AC_PROG_CXX is all it takes.
> 
> Do I do something subtly wrong or is g++ merely much better at
> generating code then gcc?

That's a really interesting question.  I'm not aware of anything very
specific that would help g++ to generate much better code, but of
course the two front ends do produce slightly different intermediate
code for the back ends.  I don't think there's any way to find out
without some detailed study.

Andrew.