Re: LLVM ARM NEON VMUL.f32

2013-03-20 Thread Renato Golin
On 20 March 2013 08:11, Kristof Beyls wrote: > ยท **Does this result in non-compliance of IEEE754 regarding > denormals? NaN? INFs? Something else? > Yes, but only slightly. ;) I don't want to treat this question as black and white because the penalty is severe, but I also don't want pe

Re: LLVM ARM NEON VMUL.f32

2013-03-20 Thread Mans Rullgard
On 19 March 2013 21:56, Renato Golin wrote: > Hi folks, > > I found an issue while fixing a test using the wrong VMUL.f32, and I'd like > to know what should be our choice on this topic that is slightly > controversial. > > Basically, LLVM chooses to lower single-precision FMUL to NEON's VMUL.f32

Re: LLVM ARM NEON VMUL.f32

2013-03-20 Thread Peter Maydell
On 19 March 2013 21:56, Renato Golin wrote: > Basically, LLVM chooses to lower single-precision FMUL to NEON's VMUL.f32 > instead of VFP's version because, on some cores (A8, A5 and Apple's Swift), > the VFP variant is really slow. > > This is all cool and dandy, but NEON is not IEEE 754 compliant

RE: LLVM ARM NEON VMUL.f32

2013-03-20 Thread Kristof Beyls
Hi Renato, I think to be able to make the best possible judgement here, answers to the following questions would be needed: * Does this result in non-compliance of IEEE754 regarding denormals? NaN? INFs? Something else? * Also, does the C/C++ standard say something about IEEE