similar to: [LLVMdev] Proposal for adding rounding variant of fpto?i instructions

Hi Peter, > I would appreciate comments/feedback on this proposal to extend the > fpto?i instructions to support rounding. I think this might be useful. Actually, LLVM specifies that fpto?i convert their operand into the nearest (rounding towards zero) signed integer value. Do you have other rounding modes in mind? Currently I use custom metadata to represent conversions with other rounding

Hi, I would appreciate comments/feedback on this proposal to extend the fpto?i instructions to support rounding. This is my first proposed significant extension to LLVM so I'd like to know if I'm completely off base here. First of all, I noticed the convert* intrinsics corresponding to the CONVERT_RNDSAT InstructionDAG. I propose not to build my work on top of these as they seem to be

I'll give some data points from our OpenVMS Itanium (and Alpha) platforms where we support multiple IEEE modes and dynamic rounding in our C and Fortran compilers (we don't have actual FENV_ACCESS in our C product but you can come close). On the command line, you get to pick IEEE modes with:   /IEEE_MODE         /IEEE_MODE=option         /IEEE_MODE=DENORM_RESULTS (D)      Selects the

Peter, Is there a way to make this flag globally available? Metadata can be fairly expensive to handle at each node when in many cases it is a global flag and not a per operation flag. > -----Original Message----- > From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu] > On Behalf Of Robert Quill > Sent: Thursday, September 08, 2011 3:24 AM > To: Peter

> > The only issue I see is that since we also assume FP operations have no > side effects by default there is no difference between llvm.rint and > llvm.nearbyint. I wouldn’t have a problem with dropping llvm.rint > completely. The forthcoming C standard ( http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2454.pdf, 7.12.9.8) defines new function, `roundeven`, which implements

Some clarification after getting feedback from Craig Topper…. It’s probably best to say in the documentation that the llvm.nearbyint and llvm.rint functions “assume the default rounding mode, roundToNearest”. This will allow the optimizer to transform them as if they were rounding to nearest without requiring backends to use an encoding that enforces roundToNearest as the rounding mode for these

> > One concern with replacing llvm.rint and llvm.nearbyint with > llvm.roundeven makes it difficult to turn back into a libcall if the > backend doesn't have an instruction for it. You can't just call the > roundeven library function since that wouldn't exist in older libm > implementations. So ideally you would know which function was originally > used in the

Hi, This is my proposal to add floating point accuracy support to LLVM. The intention is that the frontend may provide metadata to signal to the backend that it may select a less accurate (i.e. more efficient) instruction to perform a given operation. This is primarily a requirement of OpenCL, which specifies that certain floating point operations may be computed inaccurately. Comments

Hi, What is the rounding mode for the fptrunc instruction? Round to zero? Round to nearest? Or undefined? Regards, Jon

I couldn't find anything in the chron or timeDate packages, and a good search yielded rounding to the nearest half hour, which I don't want. The data: structure(list(Date = structure(c(1209625080, 1209641460, 1209652500, 1209676800, 1209682860, 1209692100, 1209706980, 1209722580, 1209726300, 1209739620, 1209762780, 1209765720, 1209770520, 1209791040, 1209812580, 1209829920,

POSIXct/lt supports fractional seconds (see Sub-second Accuracy section of man page), but there seem to be some inconsistencies in their handling. Converting to POSIXlt and back does not give back the same time for times before the origin: > t0 <- as.POSIXct('1934-01-05 23:59:59.00001') > t0 [1] "1934-01-06 00:00:00 EST" # rounding issue, see below >

Hi Peter, This sounds like I really good idea. One thing that did occur to me though from an OpenCL point of view is that ULP accuracy requirements can differ for embedded and full profile so that may need to be handled somehow. Thanks, Rob On Wed, 2011-09-07 at 21:55 +0100, Peter Collingbourne wrote: > Hi, > > This is my proposal to add floating point accuracy support to LLVM. >

The LLVM IR reference manual states, for fptosi: "The ‘fptosi’ instruction converts its floating-point <http://llvm.org/docs/LangRef.html#t-floating> operand into the nearest (rounding towards zero) signed integer value." I interpreted this to mean that it rounds: The nearest integer to 0.3 is 0. The nearest integer to 0.9 is 1. The nearest integer to 0.5 is either 0 or 1. And

Dear all, A hopefully simple question: how do I round a series of values (held in an object) to the nearest 5? I've checked out trunc, round, floor and ceiling, but these appear to be more tailored towards rounding decimal places. Thanks, Steve _________________________________________________________________ icons.

If fptosi takes 0.9 -> 0, then that is not 'rounding' in any sense I'm aware of (IEEE754 or otherwise). Rounding (in the IEE754 sense) determines how a number is converted when it is halfway between two candidate results. (see round(), ceil(), floor()). fptosi seems to model the behavior of a C cast from float to int, which truncates the fractional bits (as in trunc()). Steve

> On Sep 4, 2020, at 2:40 PM, Neil Nelson via llvm-dev <llvm-dev at lists.llvm.org> wrote: > >> If fptosi takes 0.9 -> 0, then that is not 'rounding' in any sense I'm aware of (IEEE754 or otherwise). >> Rounding (in the IEE754 sense) determines how a number is converted when it is halfway between two >> candidate results. (see round(), ceil(),

I've recently been looking at how to implement in LLVM IR the rounding of floating point values when casting using different rounding modes and I've hit some problems. It seems that when casting down floats to less precise types the ``fptrunc`` LLVM IR instruction is used. The LLVM language reference suggests that it just truncates the value (which would be equivalent to rounding towards

Hi, Is there a recommended way to round to the nearest whole (x86 RC field of FPU control = 00) ? It appears an intentional truncation instruction is generated (if ms disassembly is correct): IRBuilder<>::CreateFPToSI %1 = fptosi double %0 to i64 00370025 fisttp qword ptr [esp] Thanks, Bob -------------- next part -------------- An HTML attachment was

Hi all, I've got a matrix of fractional data that is all positive and greater than zero that I would like to "loosely" classify, for lack of a better word. It looks something like this : 1.07 1.11 1.27 1.59 0.97 0.76 2.23 0.98 0.71 0.88 1.19 1.02 What I'm looking for is a way to round these numbers to the nearest 0.25, i.e. the above matrix would be

On Tue, Jan 27, 2015 at 7:59 PM, Sanjoy Das <sanjoy at playingwithpointers.com> wrote: > On Tue, Jan 27, 2015 at 7:44 PM, David Majnemer > <david.majnemer at gmail.com> wrote: > > On Tue, Jan 27, 2015 at 7:23 PM, Sanjoy Das < > sanjoy at playingwithpointers.com> > > wrote: > >> > >> Hi David, > >> > >> I spent some time