similar to: Update on strict FP status

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 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

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

> On Jan 9, 2018, at 1:53 PM, Kaylor, Andrew via cfe-dev <cfe-dev at lists.llvm.org> wrote: > > I think we’re going to need to create a new mechanism to communicate strict FP modes to the backend. I think we need to avoid doing anything that will require re-inventing or duplicating all of the pattern matching that goes on in instruction selection (which is the reason we’re

Andrew Kaylor wrote: >In general, the current "strict FP" handling stops at instruction >selection. At the MachineIR level we don't currently have a mechanism >to prevent inappropriate optimizations based on floating point >constraints, or indeed to convey such constraints to the backend. >Implicit register use modeling may provide some restriction on some

On Tue, Jan 09, 2018 at 06:53:51PM +0000, Kaylor, Andrew via cfe-dev wrote: > I think we're going to need to create a new mechanism to communicate > strict FP modes to the backend. I think we need to avoid doing anything > that will require re-inventing or duplicating all of the pattern > matching that goes on in instruction selection (which is the reason >

> ... math errno ... I wouldn't recommend to anyone that they should rely on math errno (because I don't trust libraries to correctly support it). My goal here was to incorporate our existing support for it into the rest of what I'm trying to document. My understanding is that for clang this primarily controls whether or not we feel free to substitute intrinsics for recognized

On 9 Jan 2018 22:55, "John McCall via llvm-dev" <llvm-dev at lists.llvm.org> wrote: On Jan 9, 2018, at 3:50 PM, Kaylor, Andrew <andrew.kaylor at intel.com> wrote: >The standard argument against trying to introduce "scope-like" mechanisms to LLVM IR is inlining; >unless you're going to prevent functions that use stricter/laxer FP rules from being inlined

> > 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

I think we're going to need to create a new mechanism to communicate strict FP modes to the backend. I think we need to avoid doing anything that will require re-inventing or duplicating all of the pattern matching that goes on in instruction selection (which is the reason we're currently dropping that information). I'm out of my depth on this transition, but I think maybe we could

>The standard argument against trying to introduce "scope-like" mechanisms to LLVM IR is inlining; >unless you're going to prevent functions that use stricter/laxer FP rules from being inlined >into >each other (which sounds disastrous), you're going to need to communicate strictness on an >instruction-by-instruction basis. If the backend wants to handle that by

+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

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, A question came up in a code review (https://reviews.llvm.org/D72820) about whether or not to allow fast-math flags to be applied to constrained floating point intrinsics (http://llvm.org/docs/LangRef.html#constrained-floating-point-intrinsics). This has come up several times before, but I don't think we've ever made a decision about it. By default, the optimizer assumes that

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

> > I'm not sure why this is an issue. Yes, these two intrinsics depend > on the current rounding mode according to the C standard, and yes, > LLVM in default mode assumes that the current rounding mode is the > default rounding mode. But the same holds true for many other > intrinsics and even the arithmetic IR operations like add. Any other intrinsic, like `floor`,

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,

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 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