[cfe-dev] GCC extensions not implemented yet

Hal Finkel hfinkel at anl.gov
Wed Oct 16 09:36:22 PDT 2013


----- Original Message -----
> Fixed point arithmetic is basically integer arithmetic that saturates
> instead of wrapping zero.  I want to add saturating integer
> operations to the IR.  I could implement these by adding intrinsic
> functions rather than real opcodes, but I would really like to have
> vectorization support someday.

There seems to be a fair amount of overlap here with what OpenCL needs.

 -Hal

> 
> Note, the operations are defined by the technical report in section
> 4.1.6.
> 
> I have read http://clang.llvm.org/get_involved.html and will commit
> to it.  I do not know if there is "Evidence of a significant user
> community".  It is supported by gcc and ACE, but I have no insight
> beyond that.
> 
> -----Original Message-----
> From: Hal Finkel [mailto:hfinkel at anl.gov]
> Sent: Tuesday, October 15, 2013 7:06 PM
> To: Mark Schimmel
> Cc: cfe-dev at cs.uiuc.edu
> Subject: Re: [cfe-dev] GCC extensions not implemented yet
> 
> Mark,
> 
> Can you explain more about what you have in mind. I suppose that the
> semantic analysis portions are pretty well defined, but what would
> this mean in terms of code generation?
> 
>  -Hal
> 
> ----- Original Message -----
> > 
> > 
> > 
> > 
> > http://clang.llvm.org/docs/UsersManual.html says “ clang does not
> > support decimal floating point types ( _Decimal32 and friends) or
> > fixed-point types ( _Fract and friends); nobody has expressed
> > interest
> > in these features yet, so it’s hard to say when they will be
> > implemented ”.
> > 
> > 
> > 
> > Synopsys is interested in the fixed point data types and is
> > starting
> > to add extensions for it. Is this an extension the community would
> > want in the clang/llvm tree?
> > 
> > 
> > 
> > See section 4:
> > http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1275.pdf
> 

-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory




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