[llvm-dev] Vectorization with fast-math on irregular ISA sub-sets
James Molloy via llvm-dev
llvm-dev at lists.llvm.org
Mon Feb 8 13:35:26 PST 2016
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.
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