similar to: [LLVMdev] fptrunc and undefined results

On Mon, 31 Mar 2008, Jon Sargeant wrote: > The fptrunc instruction states "If the value cannot fit within the > destination type, ty2, then the results are undefined." This is fine, but > what about other floating-point operations that can overflow? For example, > does 'mul double 1.0e300, 1.0e300' produce +infinity or is it undefined? It is defined by IEEE to

The fptrunc instruction states "If the value cannot fit within the destination type, ty2, then the results are undefined." This is fine, but what about other floating-point operations that can overflow? For example, does 'mul double 1.0e300, 1.0e300' produce +infinity or is it undefined? I think LLVM should treat floating-point overflows consistently. On a similar note,

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

On Sun, May 29, 2016 at 6:18 AM, Alexander Cherepanov <ch3root at openwall.com> wrote: > On 2016-05-20 19:58, David Majnemer via llvm-dev wrote: > >> I've come across this issue before and came to the following conclusion: >> - We are not obligated to support objects that large, C11 5.2.4.1/1 only >> requires that we support objects of size 65535! >> >

On 2016-05-20 19:58, David Majnemer via llvm-dev wrote: > I've come across this issue before and came to the following conclusion: > - We are not obligated to support objects that large, C11 5.2.4.1/1 only > requires that we support objects of size 65535! Right, the standard doesn't require it. But I guess you don't imply that it's fine for clang to silently miscompile

Hi, I have a test case would fail due to instruction combine cast from floor to floorf. double d = 1024.0 - 1.0 / 32768.0; extern double floor(double); extern float floorf(float); extern void abort(); int main() { float f1 = (float)floor(d); if ((int)f1 != 1023) abort (); return 0; } My question is: Is the transformation legal for this case? Thanks, Shiva

> On Mar 17, 2017, at 06:31, Hal Finkel via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > Hi Shiva, > > Thanks for reporting this. It looks like a bug to me (from r292855). Can you file a bug report? Matt, can you fix this? > > -Hal https://reviews.llvm.org/D31107

Dear Tom, The change in the Fedora RPM from using R's internal BLAS to external BLAS means the Fedora R binary now fails one of R's regression tests, specifically: tests/reg-BLAS.R. You can run this code by hand to verify the issue. As noted in the R administration and Installation Manual, "R relies on ISO/IEC 60559 compliance of an external BLAS. This can be broken if for example

Hola a tod en s. Realizando el calculo de encontrar la raíz quinta de -0.5, la cual dígito de la siguiente manera (-0.5)^(1/5) El resultado que me arroja R es NaN. Averiguando un poco entre las ayuda de las funciones aritméticas encuentro el siguiente comentario Users are sometimes surprised by the value returned, for example why (-8)^(1/3) is NaN. For double inputs, R makes use of IEC 60559

Dear R-users with a bit of grief I had to repeat an extensive analysis because I did not suspect (and therefore did not read the documentation) that round was implemented as "for rounding off a 5, the IEC 60559 standard is expected to be used, 'go to the even digit'", resulting in round(1.5) = 2 round (2.5) = 2. As a non-mathematician I am both puzzled and intrigued by

No sé si he entendido bien la pregunta, pero creo que lo que quieres obtener es esto: (as.complex(-0.5)^(1/5)) Saludos,Salva > To: r-help-es en r-project.org > From: canadasreche en gmail.com > Date: Thu, 15 Oct 2015 10:45:10 +0200 > Subject: Re: [R-es] potencia fracional de un número negativo > > Hola. > No sé si va por aquí, pero prueba a quitar el paréntesis a (-0.5) >

On 07/02/2015 04:44 PM, David Keaton wrote: > On 07/02/2015 03:17 AM, Kuperstein, Michael M wrote: >> You want to redefine ["won't break the program"], by specifying a new >> abstract machine, which is >> more conservative than standard C/C++. The proper way to do that would, >> I believe, be to work towards setting up a working group within the >>

On Sep 11, 2012, at 1:03 PM, "Villmow, Micah" <Micah.Villmow at amd.com> wrote: > > From: Villmow, Micah > Sent: Tuesday, September 11, 2012 12:51 PM > To: llvm-commits at cs.uiuc.edu > Subject: Proposal: New IR instruction for casting between address spaces > > Problem: > Bit casting between pointers of different address spaces only works if all

From: Villmow, Micah Sent: Tuesday, September 11, 2012 12:51 PM To: llvm-commits at cs.uiuc.edu Subject: Proposal: New IR instruction for casting between address spaces Problem: Bit casting between pointers of different address spaces only works if all address space pointers are the same size. With changes from email chain [1][2], support for different pointer sizes breaks the bitcast instruction

I've come across this issue before and came to the following conclusion: - We are not obligated to support objects that large, C11 5.2.4.1/1 only requires that we support objects of size 65535! Their guidance for maximum object size is stated to be half of SIZE_MAX in C11 K.3.4/4 which is typically equivalent to PTRDIFF_MAX. - The expectation that PTRDIFF_MAX is more or less a proxy for the

Hello Folks, I have a couple of questions - one about a basic UPS choice I am to make for a small UK office environment and the second about NUT Windows support. For the UPS, I have 2 or 3 servers, a phone system and a switch i.e. a basic : - Dell R410 1U (2x IEC) - Dell SC1425 1U (1x IEC) - Mitel 3300 CXi phone system (1x IEC) - Netgear GS748T switch (1x IEC) It would be good to also be able

Hello, in some operations there is a ty2 type, for example in truncate. What is the most right way to get it ? I have seen some EVT types, but this is connected to DAG... and I don't believe that there is no easy way to get ty2 with one call function. -------------- next part -------------- An HTML attachment was scrubbed... URL:

Hi, On Sep 11, 2012, at 2:30 PM, Villmow, Micah wrote: > > >> -----Original Message----- >> From: Dan Gohman [mailto:gohman at apple.com] >> Sent: Tuesday, September 11, 2012 1:28 PM >> To: Villmow, Micah >> Cc: llvmdev at cs.uiuc.edu >> Subject: Re: [LLVMdev] Proposal: New IR instruction for casting between >> address spaces >> >>

It's an optimization opportunity! When behavior is undefined, we're free to interpret it to be "whatever makes optimization easiest." If the two do actually happen to alias, well, it's the programmer's fault anyways, because they were doing something undefined! --Owen On Nov 13, 2007, at 4:13 PM, Wojciech Matyjewicz wrote: > Hi! > > While investigating