[llvm-dev] Vectorization with fast-math on irregular ISA sub-sets

[James Molloy via llvm-dev]

The conditions in which the LV kicks in are different for FP and integer loops. The LV always kicks in for non-FP loops AFAIK

> On 8 Feb 2016, at 20:51, Renato Golin <renato.golin at linaro.org> wrote:
> 
> On 8 February 2016 at 19:25, James Molloy <James.Molloy at arm.com> wrote:
>>> For 16275, the fix is to disable loop vect. for no-fast-math + hasUnsafeAlgebra.
>> 
>> Do you think there is a set of people that care about IEEE accuracy in so far that they don't want FTZ, but *are* happy to reassociate FP operations? That seems fairly niche to me?
> 
> No. But I also don't want to disable the vectorizer for integer
> arithmetic. I'm guessing hasUnsafeAlgebra is not just for FZ but also
> NaNs and Infs, so disabling the vectorization of loops that have any
> of those unless safe-math is chosen seems simple enough to me.
> 
> cheers,
> --renato
>