[cfe-dev] OpenMP support in CLANG: A proposal

Olaf Krzikalla Olaf.Krzikalla at tu-dresden.de
Thu Nov 8 04:48:30 PST 2012

Am 08.11.2012 04:20, schrieb Mahesha HS:
> GCC ( g++ ) happily reports *un-declared* error for the variable VarA
> when I do not pass -fopenmp option, and abort the compilation. Yes,
> OpenMP spirit is clearly broken here.  Though, I did not test the
> other compilers, I guess that they follow GCC for whatever the
> reasons.
MSVC rejects the code.

> And, now, if Clang starts fighting against these clearly violated
> rules, it is very probable that users will start their voice against
> it.
I don't think so. I haven't seen something like this anywhere in 
production code. It is just way over the top (I believe it is even a 
non-intentionally extension of gcc introduced by an unified handling of 
Regarding side effects in expressions, while these might be considered 
evil, they are actually allowed by the OpenMP standard. But they don't 
impose any problems to the implementation.

A program shall compile and run with and without -fopenmp. It is not 
required that both variants yield the same output.

Best Olaf

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