search for: denormalized

Hi all, While reviewing a recent clang documentation change, I became aware of an issue with the way that clang is handling FP denormals. There is currently some support for variations in the way denormals are handled, but it isn't consistent across architectures and generally feels kind of half-baked. I'd like to discuss possible solutions to this problem. First, there is a clang

On Mon, Sep 16, 2019 at 9:43 PM Matt Arsenault via cfe-dev < cfe-dev at lists.llvm.org> wrote: > > > On Sep 16, 2019, at 19:57, Kaylor, Andrew via llvm-dev < > llvm-dev at lists.llvm.org> wrote: > > > Do we need an ftz fast-math flag? > > > This would be useful for matching a handful of AMDGPU instructions (a fmad > that only always flushes being the

Our processor also has some issues regarding the handling of denormals - scalar and vector - and we ran into a related problem only a few days ago. The v3.8 compiler has done a lot of good work on optimisations for floating-point math, but ironically one of them broke our implementation of 'nextafterf'. The desired code fragment (FP32) is: float xAbs = fabsf(x); since we know our

...alculations (why is beyond me). Now, the work-around is to prevent some signals from going to exacly zero. Have a look at how the VERY_SMALL macro is currently being used. It's defined as 0 for fixed-point, but 1e-15f for float. By adding that value to the right signal(s), you can prevent denormalized numbers from being generated. The key is to find that place or those places. A profiler may be able to tell you where the problem happens so you can add VERY_SMALL just before that place. I suspect that just doing that at the output of the preprocessor may be enough but I'm not sure. Che...

IEEE-754R defines a normal floating point number as: 2.1.38 normal number: For a particular format, a finite non-zero floating-point number with magnitude greater than or equal to a minimum bemin value, where b is the radix. Normal numbers can use the full precision available in a format. In this standard, zero is neither normal nor subnormal. This implies that a denormal is not a normal number.

Hi, > James, is that a correct assessment? Yes, it is also my belief that the only way ARMv7 NEON differs from IEEE754 is lack of denormal support. James > On 11 Feb 2016, at 10:53, Renato Golin <renato.golin at linaro.org> wrote: > > Hal, > > I had a read on the ARM ARM about VFP and SIMD FP semantics and my > analysis is that NEON's only problem is the

On 06/07/2013 06:49 AM, Arnold Schwaighofer wrote: > > On Jun 7, 2013, at 3:14 AM, Renato Golin <renato.golin at linaro.org> wrote: > >> On 7 June 2013 08:48, Tobias Grosser <tobias at grosser.es> wrote: >> When to set which subtarget feature is a policy decision, where I honestly don't have any opinion on for clang. The best is probably to mirror the gcc

----- Original Message ----- > From: "Renato Golin" <renato.golin at linaro.org> > To: "Hal Finkel" <hfinkel at anl.gov> > Cc: "James Molloy" <James.Molloy at arm.com>, "Nadav Rotem" <nrotem at apple.com>, "Arnold Schwaighofer" > <aschwaighofer at apple.com>, "LLVM Dev" <llvm-dev at

| For programs that have mixed precision requirements for floating point | operations we probably need to do this according to the fast math flags. | Until we get there, a good first step would probably be to provide a | global option similar to -enable-no-infs-fp-math that specifies if | denormals should be allowed or not. This would allow the user to specify | the precision requirements, without

Hello R users, My problem is that the data I've got is in the minimum number of columns with each ward (geographic area) appearing multiple times. The first 30 terms look like this > HHum02 CASW Btype Yr CO2Group NumVeh 170597 00CCFA CARS 2002 C 2 170598 00CCFA CARS 2002 D 2 170599 00CCFA CARS 2002 E 22 170600 00CCFA CARS 2002

I am building a relatively trivial application to try to learn my way around Rails. I am having difficulty understanding how to navigate a heavily denormalized hierarchy. Could someone direct me to a bare-bones explanation of using rails to navigate database hierarchies? I am an experienced developer. Most of my work has been desktop client server, high performance, or server to server interprocess work in large scale systems (8K plus users). However,...

Hal, James, My plan to disable vectorization on NEON FP had two steps: 1. Create the infrastructure to detect unsafe FP maths and force NEON FP via fast-math. 2. Use -mfpmath=neon/sse to fine-tune the flags even further, but this needs a lot of work in IR. The expected behaviour is to have most performance with least options, but with correctness in mind. So, we can't vectorize FP loops

On Jun 7, 2013, at 3:14 AM, Renato Golin <renato.golin at linaro.org> wrote: > On 7 June 2013 08:48, Tobias Grosser <tobias at grosser.es> wrote: > When to set which subtarget feature is a policy decision, where I honestly don't have any opinion on for clang. The best is probably to mirror the gcc behavior on linux targets. > > Not really, since GCC has no special

..., I''m new to RoR and exploring its use with an existing application. One thing I can''t seem to find much detail on is using database triggers. All RoR examples and tutorials I''ve seen are very basic saving data back to a single table. My use case includes a somewhat denormalized DB that uses triggers to store data in multiple tables on occassion. I currently use IBM DB2 9. Can anyone explain how to use DB triggers in a complimentary fashion with RoR? Or, I''m assuming that because I could not find examples of how to work with triggers, the more elegant RoR mo...

Hi Mark, Code below: int16_t* samples; int16_t* fbSilenceFrame; void *fSpeexState; float eng(0.f); int speexFrameSize(0); speex_encoder_ctl(speexState, SPEEX_GET_FRAME_SIZE, &speexFrameSize); for (int i = 0; i < speexFrameSize; i++) { eng += samples[i] * samples[i]; } if (eng / speexFrameSize < 3.f) { memcpy(samples, silenceFrame, speexFrameSize * sizeof(int16_t)); } where

On 12 October 2016 at 15:05, Hal Finkel <hfinkel at anl.gov> wrote: > This is something we need to understand. No, there's not always an error bar. With FMA formation and without non-IEEE-compliant optimizations (i.e. fast-math), the optimized answer should be identical to the non-optimized answer. What about architectures that this is never respected, like Darwin? In the general

...ct result, and not obtaining this exact result is surprising. For example, I would expect that adding/multiplying two small integers gives the exact result, or that fmin/fmax give the correct result if no nans are involved, or that comparisons yield the correct answer (again in the absence of nans, denormalized numbers etc.). The case here -- rint(0.5) -- involves an input that can be represented exactly, and an output that can be represented exactly (0.0). Neither nans, infinities, nor denormalized numbers are involved. In this case I do expect the correct answer, even with full floating point operation...

On 06/10/2013 01:56 AM, David Tweed wrote: > | For programs that have mixed precision requirements for floating point > | operations we probably need to do this according to the fast math flags. > | Until we get there, a good first step would probably be to provide a > | global option similar to -enable-no-infs-fp-math that specifies if > | denormals should be allowed or not. This

On 7 June 2013 08:48, Tobias Grosser <tobias at grosser.es> wrote: > When to set which subtarget feature is a policy decision, where I honestly > don't have any opinion on for clang. The best is probably to mirror the gcc > behavior on linux targets. > Not really, since GCC has no special behaviour for Darwin, AFAIK. My change will only generate SP-FP on NEON for A5 and A8

...btaining this exact result is surprising. For example, I would > expect that adding/multiplying two small integers gives the exact > result, or that fmin/fmax give the correct result if no nans are > involved, or that comparisons yield the correct answer (again in the > absence of nans, denormalized numbers etc.). > > > The case here -- rint(0.5) -- involves an input that can be > represented exactly, and an output that can be represented exactly > (0.0). Neither nans, infinities, nor denormalized numbers are > involved. In this case I do expect the correct answer, even wit...