search for: chawla

...at i-loop level? We were operating under the assumption of 'conservatively correct' behavior of alias analysis in the function scope? Thanks, Pankaj From: Finkel, Hal J. <hfinkel at anl.gov> Sent: Tuesday, March 17, 2020 11:50 AM To: Hiroshi Yamauchi <yamauchi at google.com>; Chawla, Pankaj <pankaj.chawla at intel.com> Cc: llvm-dev at lists.llvm.org Subject: Re: [llvm-dev] valid BasicAA behavior? BasicAA should return a result that is valid for the particular SSA values it is provided, valid at points in the control flow where it would be valid to use both SSA values si...

...sure. I think umax will not be added if we can prove the predicate as known. I am not sure whether umax will get simplified if we add nuw to the expressions. -Pankaj -----Original Message----- From: Sanjoy Das <sanjoy at playingwithpointers.com> Sent: Sunday, August 25, 2019 1:53 PM To: Chawla, Pankaj <pankaj.chawla at intel.com> Cc: Philip Reames <listmail at philipreames.com>; llvm-dev at lists.llvm.org Subject: Re: [llvm-dev] missing simplification in ScalarEvolution? I didn't step through this in a debugger, but I suspect we could fix the problem by: 1. Teaching SC...

Hi Pankaj, On Tue, Mar 13, 2018 at 1:55 PM, Chawla, Pankaj <pankaj.chawla at intel.com> wrote: > Thanks for the reply! > Would it be possible for you to implement this? I don't have cycles for this right now, but if you file a bug I can give this a shot when I have time later. Even in the best case this will have to at least wait...

...ime whether to base pointer overlaps if the accessed range is known. LoopAccessAnalysis (for vectorization) does this. For the original example, if the loop outer loops is unrolled by an even factor, the non-overlapping becomes more obvious in SSA. Michael ________________________________ From: Chawla, Pankaj <pankaj.chawla at intel.com> Sent: Tuesday, March 17, 2020 16:03 To: Finkel, Hal J. <hfinkel at anl.gov>; Hiroshi Yamauchi <yamauchi at google.com> Cc: llvm-dev at lists.llvm.org <llvm-dev at lists.llvm.org>; Kruse, Michael <michael.kruse at anl.gov> Subject: R...

This sounds fine to me (and sorry for the delay!). -- Sanjoy On Mon, Mar 12, 2018 at 1:09 PM, Chawla, Pankaj <pankaj.chawla at intel.com> wrote: > Hi Sanjoy, > > So what is the verdict on this issue? > > Thanks, > Pankaj > > > -----Original Message----- > From: Chawla, Pankaj > Sent: Monday, February 26, 2018 11:12 AM > To: Sanjoy Das <sanjoy at playing...

Thanks for the suggestion but datalayout info did not solve the problem! -Pankaj -----Original Message----- From: Philip Reames <listmail at philipreames.com> Sent: Tuesday, August 20, 2019 5:26 PM To: Chawla, Pankaj <pankaj.chawla at intel.com>; llvm-dev at lists.llvm.org Subject: Re: [llvm-dev] missing simplification in ScalarEvolution? Try adding a datalayout with pointer size information to your reduced case, and see what happens.  Not sure this is your problem, but I've been bitten by th...

Hi Pankaj, On April 14, 2017 at 4:55:16 PM, Chawla, Pankaj (pankaj.chawla at intel.com) wrote: > I have attached the IR I got by compiling with -O2. This is just before we widen the IV. Thanks! > To get the backedge taken count info I ran indvars on it and then replaced zext with sext. > > I think regardless of where we decide to add...

Hi Sanjoy, Thanks for the reply! Would it be possible for you to implement this? You know the codebase better than I do. Thanks, Pankaj -----Original Message----- From: Sanjoy Das [mailto:sanjoy at playingwithpointers.com] Sent: Tuesday, March 13, 2018 1:34 PM To: Chawla, Pankaj <pankaj.chawla at intel.com> Cc: Maxim Kazantsev <max.kazantsev at azul.com>; Serguei Katkov <serguei.katkov at azul.com>; llvm-dev at lists.llvm.org Subject: Re: [SCEV] Inconsistent SCEV formation for zext This sounds fine to me (and sorry for the delay!). -- Sanjoy On...

...// Pretend the phis do not alias. It seems to be analyzing corresponding phi operands assuming the PHIs to be ‘Noalias’ to begin with. IMHO, this setup does not work correctly for loop header phis. From: Hiroshi Yamauchi <yamauchi at google.com> Sent: Tuesday, March 17, 2020 8:38 AM To: Chawla, Pankaj <pankaj.chawla at intel.com> Cc: llvm-dev at lists.llvm.org Subject: Re: [llvm-dev] valid BasicAA behavior? Perhaps BasicAA is telling that A and B don't alias during one particular iteration of the loop even though they are swapped? 1:...

...d first from the function entry block. But we obviously cannot use this if we want ScalarEvolution to be stable around 'simple' CFG changes. Thanks, Pankaj -----Original Message----- From: Sanjoy Das [mailto:sanjoy at playingwithpointers.com] Sent: Tuesday, October 18, 2016 12:01 PM To: Chawla, Pankaj Cc: llvm-dev at lists.llvm.org Subject: Re: [llvm-dev] [SCEV] inconsistent operand ordering Hi Pankaj, Chawla, Pankaj wrote: > Thanks for fixing this Sanjoy! > > I do have a few questions/suggestions on the fix if you don't mind. > > 1) Would this work correctly if the...

As far Am Mi., 18. März 2020 um 11:34 Uhr schrieb Chawla, Pankaj <pankaj.chawla at intel.com>: > >> There seems to be a bug in DI, see Felipe's answer. > Maybe I missed something. There seems to be no resolution to the problem. How can DA fix this without help from alias analysis? DependenceInfo is not using the AA interface correc...

...osed to relying on ScalarEvolution to deduce it. Moving it to a different location can be done separately. Do you agree? Thanks, Pankaj -----Original Message----- From: Sanjoy Das [mailto:sanjoy at playingwithpointers.com] Sent: Thursday, April 13, 2017 8:35 PM To: llvm-dev at lists.llvm.org; Chawla, Pankaj Subject: Re: [llvm-dev] Question on induction variable simplification pass Hi Pankaj, On April 12, 2017 at 5:22:45 PM, Chawla, Pankaj via llvm-dev (llvm-dev at lists.llvm.org) wrote: > It looks like the induction variable simplification pass prefers doing > a zero-extension to comp...

Am Mi., 18. März 2020 um 18:15 Uhr schrieb Chawla, Pankaj <pankaj.chawla at intel.com>: > > >> DependenceInfo is not using the AA interface correctly. Either DI has to be fixed, or another method added to AA that gives additional guarantees. Please see the bug report for details. > > Thanks for updating the bug report but G...

Am Di., 17. März 2020 um 16:56 Uhr schrieb Chawla, Pankaj via llvm-dev <llvm-dev at lists.llvm.org>: > All I am expecting from DA is a direction vector containing (*). There seems to be a bug in DI, see Felipe's answer. > I think the main problem is that currently there is no exact way DA can query AliasAnalysis in a ‘conservati...

I''m trying to manipulate the following facter variable: ipaddress => 10.85.207.2 What I need is the second group of digits. If it''s 84 then location is A, but if it''s 85 then location is B. In puppet I couldn''t grab this second set of digits, but maybe there is a way? I''ve already tried to make a custom fact, but my ruby knowledge is *ahem* pretty

Hi, It looks like ScalarEvolution bails out of loop backedge computation if it cannot prove the IV stride as either positive or negative (based on loop control condition). I think this logic can be refined for signed IVs. Consider this simple loop- void foo(int *A, int n, int s) { int i; for(i=0; i<n; i += s) { A[i]++; } } The IV of this loop has this SCEV form-

Hi Pankaj, Chawla, Pankaj via llvm-dev wrote: > It looks like ScalarEvolution bails out of loop backedge computation if > it cannot prove the IV stride as either positive or negative (based on > loop control condition). I think this logic can be refined for signed IVs. > > Consider this simple l...

...ly to avoid infinite loops (see ScalarEvolution::PendingLoopPredicates). I don't think there is a nice and easy fix here. We can try to find some specific property of the IV we can exploit here to make this work, but the general problem will remain. -- Sanjoy On Thu, Feb 8, 2018 at 2:19 PM, Chawla, Pankaj <pankaj.chawla at intel.com> wrote: > Hi Sanjoy, > > > > SCEV is behaving inconsistently when forming SCEV for this zext instruction > in the attached test case- > > %conv5 = zext i32 %dec to i64 > > > > If we request a SCEV for the instruction, it...

...o I remember had some objections.] > > — Sanjoy Off the top of my head, my concern is that expression comparison is no longer constant time, which I think is fundamental to SCEV. I may be able to dig through my notes next week, after vacation... -Andy > On Tue, Aug 8, 2017 at 3:06 PM, Chawla, Pankaj <pankaj.chawla at intel.com> wrote: >> Hi Sanjoy, >> >> Any update on this? >> Are there plans to implement this proposal? >> >> Thanks, >> Pankaj >> >> >> -----Original Message----- >> Date: Fri, 23 Sep 2016 02:09:...

Hi Sanjoy, SCEV is behaving inconsistently when forming SCEV for this zext instruction in the attached test case- %conv5 = zext i32 %dec to i64 If we request a SCEV for the instruction, it returns- (zext i32 {{-1,+,1}<nw><%for.body>,+,-1}<nw><%for.body7> to i64) This can be seen by invoking- $ opt -analyze -scalar-evolution inconsistent-scev-zext.ll But when computing