similar to: Possible bug in optimizer

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 >>

Hi all, can I access the numeric limits of the llvm types, e.g. HalfTy, FloatTy, DoubleTy, etc. in a fashion like the std numeric_limits tool? std::numeric_limits<half>::min() std::numeric_limits<half>::max() In c++API, I want to initialize values and need to know the correct range for the llvm types.... Thx Alex

On Tue, 4 May 2004, Finn S Andersen wrote: > Chris wrote in a followup: > > > Can you send the output of 'llc -o - foo.bc -debug -print-machineinstrs'? > > > Attached as "linscan". (But added the "-regalloc=linearscan" to provoke > the error). Yes, that's exactly what I meant... thanks for reading my mind! :) It looks like this is where

+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 Fedora 17 I have installed a the binary clang package clang3.0-14. When I tried to build the latest llvm/clang from source using this binary clang I get essentially two different errors: 1) In file included from /home/fceldiener/vcs/llvm/include/llvm/Support/SwapByteOrder.h:20: /usr/bin/../lib/gcc/x86_64-redhat-linux/4.7.2/../../../../include/c++/4.7.2/limits:1404:27: error: use of

On Thu, May 06, 2004 at 04:06:27PM +0200, Finn S Andersen wrote: > Chris Lattner wrote: > > >I think that we should switch to C constants in this case. Can you try > >#include <math.h> and use HUGE_VAL instead? > > > It works: > > [finna at coplin11 ~/test]$ cat tst.cpp > #include <limits> > #include <iostream> > #include

Hello, I am very new to llvm, but I need to have a fully working llvm / llvm-gcc system built and running on my fedora 21 virtual machine so I can perform some concolic testing with stp. I have installed all upgrades to fedora 21 using yum upgrade. I was able to compile and install llvm fine from the svn repository. I checked out llvm-gcc-4.2 from the repository (revision 234124). I ran

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

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 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 >

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 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

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 }

Hi all, Implementation of #pragma STDC FENV_ACCESS raises a problem: what to do if a function is called inside a region where FP environment differs from the default? If the function expects default FP mode it may work incorrectly in such case. The C2x standard draft ( http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2454.pdf) states (7.6p4): Certain programming conventions support the intended

Chris Lattner wrote: >Could you try compiling and running this program: > >--- >#include <limits> >#include <iostream> >int main() { > std::cerr << std::numeric_limits<float>::infinity() << "\n"; >} >--- > > Sure thing. It prints "0". Calling that inifinity is somewhat of a stretch, isn't it ? What on earth

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

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,

Sounds like the select lowering issue is definitely separate from the FENV work. Is there a bug report with a C or IR example? You want to generate compare and branch instead of a cmov for something like this? int foo(float x) { if (x < 42.0f) return x; return 12; } define i32 @foo(float %x) { %cmp = fcmp olt float %x, 4.200000e+01 %conv = fptosi float %x to i32 %ret = select

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