[LLVMdev] half to float intrinsic promotion

[Tom Stellard]

On Thu, Feb 12, 2015 at 11:48:17AM -0500, kewuzhang wrote:
> 
> Hi Guys, 
> 
> I am trying to promote half to float for my intrinsic math operations, 
> following class and pattern  are defined.
> 
> "
> class  S_HF__HF< string asmstr> : Intrinsic
>         <[llvm_float_ty  ],  [llvm_float_ty  ],
> 	[IntrNoMem],  
> 	!strconcat(asmstr,    "_f16")>;
> 
> def :Pat<( f16 (int_my_math_f16 f16:$src)), (F2Hsr (FEXTsr f16:$src) )>;
> 
> 
> “
> where FEXTsr is implementing the fextend type profile,   F2Hsr is implementing as the  float to half conversion .
> “int_my_math_f16”  is implementing the “S_HF__HF” profile above.
> I am just trying to 
> (1) convert the $src from f16 to f32 using FEXTsr.
> (2) use the F2Hsr to convert the f32 back to f16.
> for testing.
> however, I always got the error
> ”
> Type inference contradiction found, merging 'f32' into 'f16'
> def :Pat<( f16 (int_my_math_f16 f16:$src)), (F_2_F16sr (FEXTsr f16:$src) )>;
> 
> “
> 
> 
> Wondering what is the reason? I noticed that LLVM does not have the intrinsic type “LLVM_f16_ty”, so I always use “LLVM_float_ty” for it as long as it is a float or half.
> 

There is llvm_half_ty.  Try defining your intrinsic with that instead of
llvm_float_ty.

-Tom

> best
> 
> Kevin

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