[LLVMdev] TargetDescription string documentation

[Dale Johannesen]

On May 27, 2010, at 3:37 PMPDT, Eli Friedman wrote:

> On Thu, May 27, 2010 at 11:18 AM, Paulo J. Matos <pocmatos at gmail.com> wrote:
>> On Thu, May 27, 2010 at 7:09 PM, John Criswell <criswell at uiuc.edu> wrote:
>>> I believe what you want is documented here:
>>> 
>>> http://llvm.org/docs/LangRef.html#datalayout
>>> 
>> 
>> Just a note, since it might be a bug on the backend or documentation.
>> It says on the documentation that size for f is either 32 or 64,
>> however, sparc has 64 and 128.
> 
> It's a documentation bug; f128 refers to the LLVM type fp128 on SPARC.
> 
> -Eli

128 could also be ppcf128 on PPC, which has a completely different representation than fp128.
And f80 exists on x86.   I suppose this doc is trying to make the point that FP types can't be of arbitrary sizes while int types can be, which is a good point to make, but there should be a better way to do it than enumerating the possibilities.  FP types that are not supported on the target, e.g. f80 on Sparc, will not work well.