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Apologies: didn't notice how old this thread is before replying. On Tue, Mar 22, 2016 at 5:24 PM, Sanjoy Das <sanjoy at playingwithpointers.com> wrote: > Hi Vivek, > > [+CC Matthias, Quentin] > > Inter-procedural register allocation can be a big win, but my estimate > is that it will be challenging to complete within one summer unless > you're already familiar

Hi Sanjoy, Reading through LoopDependenceAnalysis::analyseStrongSIV(), I noticed one problem and one confusion. My confusion related to your naming of the two instructions as A and B. It's consistent all through LoopDependenceAnalysis. I'd prefer something like source and destination, so I can keep track of which is which. It didn't matter so much when you were simply proving or

No need to apologize this thread surely deserved some answers :) From my perspective this project sounds doable. I would expect the register allocation parts to be not too hard: I imagine this being just distilling a new clobber regmask after allocating a function. I would expect the challenging (or annoying) part to get a machine module pass (or a similar mechanism to influence the order in

Hi Hal, Preston! Sorry for the delay! Got busy with some offline work. I've worked on my previous code to calculate direction and distance vectors whenever possible (strong SIV, basically). I think the current code is much clearer and would like your opinions on it. I have attached the patch and also pushed to the github repo I mentioned [1]. Thanks! [1]

Hi Sanjoy, Here's a version of Banerjee and Wolfe's Exact SIV test: https://sites.google.com/site/parallelizationforllvm/weak-siv-test It assumes you've already filtered out the easy cases handled by ZIV, strong SIV, etc. I'm not confident about my uses of APInt. If you have any comments, I'd love to hear them. Thanks, Preston On Thu, Apr 12, 2012 at 5:14 AM, Sanjoy Das

Hi Félix, Sanjoy Das wrote: > Félix Cloutier via llvm-dev wrote: > > Assuming that this is a bug, what are the next steps? > > Looks like you already have a very small test case -- have you tried > sticking it in a debugger to see why SCCP thinks removing the call is > okay? > > Alternatively, file a bug at llvm.org/bugs and someone will get to it. The third

On Sat, Feb 27, 2016 at 1:41 PM, Sanjoy Das <sanjoy at playingwithpointers.com> wrote: > Just as a reality check, I wrote up a demonstration where one link > order causes a SIGFPE and another doesn't (and the program is well > defined, as far as I can tell). All TUs are compiled with -O3. This is also > an instance where we don't actually speculate an inline function,

Gents, I spent some time reading over Sanjoy's patch for LoopDependenceAnalysis. Unfortunately, an early version of these notes escaped; this is the complete review. First off, I agree with his choice to implement the SIV tests. For scientific Fortran, the SIV (and the simpler ZIV) tests cover about 85% of the cases in practice. For C and C++, I expect the percentage will be much higher.

Hi, Here is a preliminary (monolithic) version you can comment on. This is still buggy, however, and I'll be testing for and fixing bugs over the next few days. I've used your version of the strong siv test. Thanks! -- Sanjoy Das. http://playingwithpointers.com -------------- next part -------------- A non-text attachment was scrubbed... Name: patch.diff Type: application/octet-stream

On Thu, Jan 29, 2015 at 10:01 PM, Matthias Braun <matze at braunis.de> wrote: > But > (Poison > INT_MAX) <=> poison > contradicts > (X > INT_MAX) <=> false > > and I don't think you want to abandon the second rule just because x might be poison. Maybe we could define poison in such a way that it is safe to pretend it "is" false, as per our

On Sat, Jun 27, 2015 at 2:16 PM, Nuno Lopes <nunoplopes at sapo.pt> wrote: > At least in C/C++ that's UB, yes. So you cannot map every turing machine to a valid C/C++ program then. :) Also, does this mean that "daemon" programs that run continuously till they're killed by the OS (using a mechanism that is not visible in C) are effectively undefined? -- Sanjoy >

On Wed, May 16, 2018 at 1:24 AM, Nema, Ashutosh <Ashutosh.Nema at amd.com> wrote: > Hi Sanjoy, > > Your inputs really helped. > > Using “isImpliedCond”, able to relate and find the min for cases like: > > SCEV1: (-1 + (sext i32 %n.addr.058 to i64))<nsw> > SCEV2: 0 > Extra-Condition: (n.addr.058 > 7) > Result: ‘0’ (SCEV2) > > I have another case

Is copy.0 semantically equivalent to copy.1 in the following example? define void @copy.0(i8 addrspace(1)* addrspace(1)* %src, i8 addrspace(1)* addrspace(1)* %dst) { entry: %val = load i8 addrspace(1)* addrspace(1)* %src store i8 addrspace(1)* %val, i8 addrspace(1)* addrspace(1)* %dst ret void } define void @copy.1(i8 addrspace(1)* addrspace(1)* %src, i8 addrspace(1)* addrspace(1)* %dst)

Hi Wei, Wei Mi wrote: > Sanjoy and Andy, thanks a lot for your suggestions. > > On Wed, Aug 24, 2016 at 8:53 AM, Andrew Trick<atrick at apple.com> wrote: >> >>> On Aug 23, 2016, at 11:30 PM, Sanjoy Das<sanjoy at playingwithpointers.com> wrote: >>> >>> Hi Wei, >>> >>> I've not seen GCC's SCEV so I cannot

Hi all, Our use case for LLVM requires us to parse the .eh_frame sections emitted by MCJIT (for callee-saved-register spill slots, amongst other things). Does it make sense to have an in-tree parser for .eh_frame, given that it will make such tasks a lot easier? -- Sanjoy

Hi Sanjoy, I reworked the code for analyzeStrongSIV to fix a couple of mistakes, plus squeeze all the advantage possible from the symbolic manipulation provided by the SCEVs. It's sketched out here: https://sites.google.com/site/parallelizationforllvm/strong-siv-test Does it makes sense to you? Thanks, Preston On Thu, Apr 5, 2012 at 4:09 PM, Preston Briggs <preston.briggs at

> On Mar 22, 2016, at 6:04 PM, Matthias Braun via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > No need to apologize this thread surely deserved some answers :) > > From my perspective this project sounds doable. I would expect the register allocation parts to be not too hard: I imagine this being just distilling a new clobber regmask after allocating a function. I would

Here's an idea for a slightly unusual framework for poison semantics: we do it in two steps -- 1. for every bit in the program, we define a second "shadow bit", is-poison. We define the semantics of LLVM IR using this is-poison relation. So, for instance, we could say if there is a bit 'b'in address 'a' such that if is-poison['b'], then "store X to

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 until end of April because I'm leaving for a

> On Jun 11, 2015, at 12:48 AM, Sanjoy Das <sanjoy at playingwithpointers.com> wrote: > > On Thu, Jun 11, 2015 at 12:02 AM, Adam Nemet <anemet at apple.com <mailto:anemet at apple.com>> wrote: >> >>> On Jun 10, 2015, at 11:44 PM, Sanjoy Das <sanjoy at playingwithpointers.com> wrote: >>> >>>> Base is treated as unsigned so