[LLVMdev] sincos functions

Duncan Sands baldrick at free.fr
Thu Sep 15 05:29:19 PDT 2011


Hi Suresh,

>    I was trying to compare the performance of icc, gcc and llvm on the
> program almabench.c in Coyote Benchmark suite. Here is a line of code
> from the program.
>
>
>   da   = da + (ca[np][k] * cos(arga) + sa[np][k] * sin(arga)) * 0.0000001;
>
> gcc and icc are performing way better than llvm as they are using
> 'sincos' library function to compute the sin and the cos of the
> argument in a single shot. However llvm is computing sin and cos
> seperately.
>
> Is there any compiler option which can enable the code generator to
> use 'sincos' function against 'sin' and 'cos' functions seperately.

no, it hasn't been implemented in LLVM yet.  Please open a bugreport if this
optimization is important for you.

Ciao, Duncan.



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