[cfe-users] Question casually profiling Clang vs GCC

[Florian Berger via cfe-users]

On 01.08.2018 16:29, Jonas Toth via cfe-users wrote:
> 
> very interesting. My experience with normal compilation is, that clang
> is faster.

Here's the data. It's from a single run each, so it's nowhere near a
statistically sound sample.

Package                      GCC         Clang       Difference

dev-lang/python-2.7.15        2:31,640s   3:36,891s  +43%
app-arch/unzip-6.0_p21-r2     0:07,859s   0:10,094s  +28%
media-libs/opus-1.2.1         0:34,218s   0:46,750s  +37%
mail-mta/exim-4.91-r2         0:39,779s   0:54,672s  +37%
www-servers/nginx-1.12.2-r1   0:43,378s   1:03,537s  +46%
dev-db/postgresql-10.3 	      4:03,518s   6:14,859s  +54%
media-gfx/inkscape-0.92.2    28:21,146s  34:52,015s  +23%


> Could it be, that there are some precompiled headers or similar present
> on the system, that GCC utilizes?

That is possible. Where and how would I check that?

Cheers,
    Florian