similar to: Calling function from non-default floating-point environment

+cfe-dev as the discussion is now biased toward C standard. I'm not sure what problem you see here. In default mode, i.e. > when there is no "#pragma STDC FENV_ACCESS on" in effect, > then the compiler can always assume that the default rounding > mode is in effect. Well, if #pragma STDC FENV_ACCESS on is not in effect, that means > that the user has promised that at

On 7 Jan 2020, at 14:00, Kevin Neal via cfe-dev wrote: > Right here it says that dealing with non-default modes is the job of > the program or programmer: “The responsibilities associated with > accessing the floating-point environment fall on the programmer or > program that does so explicitly.” It doesn’t say compiler. It also > hedges with words like “certain ...

Hi all, This proposal is aimed at support of floating point environment, in which some properties like rounding mode or exception behavior differ from those used by default. This include in particular support of 'pragma STDC FENV_ACCESS', 'pragma STDC FENV_ROUND' as well as some other related facilities. Problem On many processors use of non-default floating mode requires

Hi all, During the review of https://reviews.llvm.org/D65997 an issue was revealed, which relates to the decision of how compiler should represents constrained floating point operations. If a floating point operation requires rounding mode or exception behavior different from the default, it should be represented by constrained intrinsic (

Which optimization did you find unsafe? Thanks, --Serge ср, 21 авг. 2019 г. в 05:12, Cameron McInally <cameron.mcinally at nyu.edu>: > On Tue, Aug 20, 2019 at 1:02 PM Serge Pavlov via llvm-dev < > llvm-dev at lists.llvm.org> wrote: > >> Hi all, >> >> During the review of https://reviews.llvm.org/D65997 >>

> > 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 all, I'm trying to put together a set of rules for how the various floating point semantic modes should be handled in clang. A lot of this information will be relevant to other front ends, but the details are necessarily bound to a front end implementation so I'm framing the discussion here in terms of clang. Other front ends can choose to follow clang or not. The existence of this set

Yes, you’re probably right about this. I was originally thinking of FENV_ACCESS as a fully strict mode of operation, but what you’re suggesting aligns with what Cameron suggested and even some of my own reasoning on other points. So, let me amend my previous proposal to say: STDC FENV_ACCESS {ON|OFF} Patch in progress. I think ON should force the following: except_behavior { strict }

Hello, at the recent EuroLLVM developer meeting in Bristol I held a BoF session on the topic "Towards implementing #pragma STDC FENV_ACCESS". I've also had a number of follow-on discussions both on-site in Bristol and online since. This post is intended as a summary of my current understanding set of requirements and implementation details covering the overall topic. I'm

Copying the list on a discussion of potentially general interest.... From: Kaylor, Andrew Sent: Friday, November 03, 2017 1:11 PM To: 'Ding, Wei' <Wei.Ding2 at amd.com>; Sumner, Brian <Brian.Sumner at amd.com>; Arsenault, Matthew <Matthew.Arsenault at amd.com> Subject: RE: clarification needed for the constrained fp implementation. Hi Wei, I've been meaning to

On 10/2/19 5:12 PM, Hal Finkel wrote: On 10/1/19 12:35 AM, Serge Pavlov via llvm-dev wrote: Hi all, This proposal is aimed at support of floating point environment, in which some properties like rounding mode or exception behavior differ from those used by default. This include in particular support of 'pragma STDC FENV_ACCESS', 'pragma STDC FENV_ROUND' as well as some other

Hi Kevin, Thanks for reaching out about this, and thanks especially for offering to help. I've had some other priorities that have prevented me from making progress on this recently. As far as I know, there is no support at all in clang for handling the FENV_ACCESS pragma. I have a sample patch somewhere that I created to demonstrate how the front end would create the constrained intrinsics

Hi Ulrich, I am interested in knowing if the current proposals also take into account the FP_CONTRACT pragma and the ability to implement options that imply a specific value for the FLT_EVAL_METHOD macro. Additionally, I am not aware of the IR being able to represent the potentially deferred loss of precision that the C language semantics provide; in particular, applying such semantics to the

On 05/23/2018 11:06 AM, Hubert Tong via llvm-dev wrote: > Hi Ulrich, > > I am interested in knowing if the current proposals also take into > account the FP_CONTRACT pragma We should already do this (we turn relevant operations into the @llvm.fmuladd. when FP_CONTRACT is set to on during IR generation). > and the ability to implement options that imply a specific value for >

On 11/03/2017 05:26 PM, 陳韋任 via llvm-dev wrote: > > > 2017-11-04 4:29 GMT+08:00 Kaylor, Andrew via llvm-dev > <llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>>: > > Copying the list on a discussion of potentially general interest…. > > *From:* Kaylor, Andrew > *Sent:* Friday, November 03, 2017 1:11 PM > *To:* 'Ding,

On 01/08/2018 07:06 PM, Richard Smith via llvm-dev wrote: > On 8 January 2018 at 11:15, Kaylor, Andrew via llvm-dev > <llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>> wrote: > > Hi Kevin, > > Thanks for reaching out about this, and thanks especially for > offering to help. I've had some other priorities that have > prevented

On Wed, May 23, 2018 at 12:19 PM, Hal Finkel <hfinkel at anl.gov> wrote: > > On 05/23/2018 11:06 AM, Hubert Tong via llvm-dev wrote: > > Hi Ulrich, > > I am interested in knowing if the current proposals also take into account > the FP_CONTRACT pragma > > > We should already do this (we turn relevant operations into the > @llvm.fmuladd. when FP_CONTRACT is

On 8 Jan 2018 19:50, "Hal Finkel via cfe-dev" <cfe-dev at lists.llvm.org> wrote: On 01/08/2018 07:06 PM, Richard Smith via llvm-dev wrote: On 8 January 2018 at 11:15, Kaylor, Andrew via llvm-dev < llvm-dev at lists.llvm.org> wrote: > Hi Kevin, > > Thanks for reaching out about this, and thanks especially for offering to > help. I've had some other

Hi all, Background I've been working on adding the necessary support to LLVM for clang to be able to support the STDC FENV_ACCESS pragma, which basically allows users to modify rounding mode at runtime and depend on the value of floating-point status flags or to unmask floating point exceptions without unexpected side effects. I've committed an initial patch (r293226) that adds

Hi Andy, I’m interested to try out your patches… I understand the scope of FENV_ACCESS is relatively wide, however I’m still curious if you managed to figure out how to prevent the SelectionDAGLegalize::ExpandNode() FP_TO_UINT lowering of the FPToUI intrinsic from producing the predicate logic that incorrectly sets the floating point accrued exceptions due to unconditional execution of the