similar to: [LLVMdev] [RFC] New function attributes for errno-setting functions

Food for thought: If you have a codebase which can't use -fno-math-errno, because it relies on errno values from math functions, it may be a more effective long-term strategy to work on modernizing your codebase, eliminating the dependencies on errno, rather than going through the trouble of adding even more complexity to compilers to keep errno support limping along. Of course, whether this

It was pointed out to me that I misunderstood what problem you were trying to solve. Sorry for the noise. Dan On Fri, Sep 13, 2013 at 2:02 PM, Dan Gohman <dan433584 at gmail.com> wrote: > Food for thought: If you have a codebase which can't use -fno-math-errno, > because it relies on errno values from math functions, it may be a more > effective long-term strategy to work on

----- Original Message ----- > > Food for thought: If you have a codebase which can't use > -fno-math-errno, because it relies on errno values from math > functions, it may be a more effective long-term strategy to work on > modernizing your codebase, eliminating the dependencies on errno, > rather than going through the trouble of adding even more complexity > to

----- Original Message ----- > > On Nov 11, 2013, at 9:30 PM, Hal Finkel <hfinkel at anl.gov> wrote: > > > ----- Original Message ----- > >> Hi Hal, all. > >> > >> I'm not sure why llvm.sqrt is 'special'. Maybe because there is a > >> SSE > >> packed sqrt instruction (SQRTPS) but not e.g. a packed sin > >>

----- Original Message ----- > Hi Hal, all. > > I'm not sure why llvm.sqrt is 'special'. Maybe because there is a > SSE > packed sqrt instruction (SQRTPS) but not e.g. a packed sin > instruction > AFAIK. This seems relevant: http://lists.cs.uiuc.edu/pipermail/llvmdev/2007-August/010248.html Chris, et al., does the decision on how to treat sqrt predate our

On Nov 11, 2013, at 10:44 PM, Hal Finkel <hfinkel at anl.gov> wrote: >> "Unlike sqrt in libm, however, llvm.sqrt has undefined behavior for >> ..." >> >> to "... produces an undefined value", with a link back to >> ##undefined-values. > > I'm not sure that helps, because it will prevents sqrt + -fno-math-errno (a readnone sqrt)

> I strongly disagree with this proposal. The purpose of this general > purpose intrinsic is to expose sqrt functionality present on many of > the architectures LLVM supports. If we defined its edge cases, we > won't be able to map it to target functionality freely on targets whose > edge cases don't match that definition. I agree the targets should be the primary focus,

On Nov 11, 2013, at 9:30 PM, Hal Finkel <hfinkel at anl.gov> wrote: > ----- Original Message ----- >> Hi Hal, all. >> >> I'm not sure why llvm.sqrt is 'special'. Maybe because there is a >> SSE >> packed sqrt instruction (SQRTPS) but not e.g. a packed sin >> instruction >> AFAIK. > > This seems relevant:

Hello everyone, The particular motivation for this e-mail is my desire for feedback on how to fix PR17758; but there is a core design issue here, so I'd like a wide audience. The underlying issue is that, because the semantics of llvm.sqrt are purposefully defined to be different from libm sqrt (unlike all of the other llvm.<libm function> intrinsics) (*), and because autovectorization

----- Original Message ----- > From: "Renato Golin" <renato.golin at linaro.org> > To: "Hal Finkel" <hfinkel at anl.gov> > Cc: "LLVM" <llvmdev at cs.uiuc.edu> > Sent: Saturday, November 23, 2013 10:53:09 AM > Subject: Re: [LLVMdev] [RFC] Identifying access to errno > > > > > On 23 November 2013 14:14, Hal Finkel <

On Fri, Sep 13, 2013 at 2:07 PM, Hal Finkel <hfinkel at anl.gov> wrote: > ----- Original Message ----- > > > > Food for thought: If you have a codebase which can't use > > -fno-math-errno, because it relies on errno values from math > > functions, it may be a more effective long-term strategy to work on > > modernizing your codebase, eliminating the

Hello, On some systems (Linux/glibc, for example), some libm math functions (like cos(double)) might set errno. It is important that we model this, in general, to prevent miscompilation (we would not, for example, want to reorder a call to cos in between a call to open and a call to perror). However, almost no code in the wild checks errno after calls to libm math functions, and this

On 23 November 2013 14:14, Hal Finkel <hfinkel at anl.gov> wrote: > On some systems (Linux/glibc, for example), some libm math functions (like > cos(double)) might set errno. It is important that we model this, in > general, to prevent miscompilation (we would not, for example, want to > reorder a call to cos in between a call to open and a call to perror). > However, almost

Oh, and I forgot a third "_doserrno" for which no amount of documentation lends itself to a consistent description of its behavior. On Sat, Nov 23, 2013 at 12:28 PM, David Majnemer <david.majnemer at gmail.com>wrote: > On Sat, Nov 23, 2013 at 9:59 AM, Hal Finkel <hfinkel at anl.gov> wrote: > >> ----- Original Message ----- >> > From: "Renato

Hi Hal, all. I'm not sure why llvm.sqrt is 'special'. Maybe because there is a SSE packed sqrt instruction (SQRTPS) but not e.g. a packed sin instruction AFAIK. As mentioned in a recent mail to this list, I would like llvm.sqrt to be defined as NaN for argument x < 0. I believe this would bring it more into line with the other intrinsics, and with the libm result, which is

On Sat, Nov 23, 2013 at 9:59 AM, Hal Finkel <hfinkel at anl.gov> wrote: > ----- Original Message ----- > > From: "Renato Golin" <renato.golin at linaro.org> > > To: "Hal Finkel" <hfinkel at anl.gov> > > Cc: "LLVM" <llvmdev at cs.uiuc.edu> > > Sent: Saturday, November 23, 2013 10:53:09 AM > > Subject: Re:

----- Original Message ----- > From: "David Majnemer" <david.majnemer at gmail.com> > To: "Hal Finkel" <hfinkel at anl.gov> > Cc: "Renato Golin" <renato.golin at linaro.org>, "LLVM" <llvmdev at cs.uiuc.edu> > Sent: Saturday, November 23, 2013 2:37:52 PM > Subject: Re: [LLVMdev] [RFC] Identifying access to errno >

On 4/29/20 4:12 PM, Reid Kleckner via llvm-dev wrote: > On Tue, Apr 28, 2020 at 12:58 PM Ejjeh, Adel via llvm-dev < > llvm-dev at lists.llvm.org> wrote: > >> Specifically, I want to be able to know when a called function does not >> have any side effects (e.g. math library functions like sqrt) >> > > Apologies for the pedantry, but I believe sqrt may

Hi All I am writing a pass which requires checking dependences, and am having trouble dealing with function calls. Specifically, I want to be able to know when a called function does not have any side effects (e.g. math library functions like sqrt), and was wondering if there are attributes that specify this behavior (I know there is the ‘noread’ attribute but wasn’t sure if there’s something

----- Original Message ----- > On 9/13/2013 2:23 PM, Hal Finkel wrote: > > > > Maybe the easiest way would be to insert an intrinsic > > @llvm.errno.read() whenever errno (as a source token) appears in > > the source as an rvalue (and do some similar thing when it appears > > as a lvalue). Thoughts? > > I think the major problem is still with