CLANG vs GCC tests of fortran/f2c program

Volodymyr Kostyrko c.kworr at gmail.com
Wed Jun 20 09:46:49 UTC 2012


Wojciech Puchar wrote:
>> 5. clang/llvm is more modular than gcc, although there are plans for
>> gcc to become as modular, it will take time.
>
> Doesn't matter how it is written, but how it performs.

That's a hard one. I remember an error in gcc loop optimizer which makes 
gcc produce SSE2 opcodes for pre-SSE2 athlon chips. Due to gcc internal 
design such errors are often seen and almost never patched as you should 
have eternal knowledge of gcc code. gcc's bugtraq is just a cemetery.

Opposing to this ones most fixes to clang touch minimal source lines and 
minimal set of files.

> Same should be used for clang. AS LONG as it is not better it should not
> be imported into base system or worse - used as default.

And why you think it's not better then gcc?

With gcc I can result in code that will hang locking some parts of 
system forever, yet with clang the code will break predictably yielding 
a core and a point on where the debugging should start. That was long 
ago and I can't correctly remember the PR's are I noted this but that 
was long ago and helped me to debug ZFS issues a lot.

The code that runs faster is not the best one. The code that is 
predictable and runs as fast as possible is.

-- 
Sphinx of black quartz judge my vow.


More information about the freebsd-questions mailing list