search for: scalarevolutions

Hey LLVMDev, I'm working on a ModulePass that uses ScalarEvolution along with several other analyses. After some debugging, it looks to me like ScalarEvolutionWrapperPass does not handle memory correctly for this case. Here's my current understanding of the problem. ScalarEvolutionWrapperPass maintains a unique_ptr to a ScalarEvolution. Calling getSE() dereferences this pointer.

Hello! I am attempting to write a program which can analyze multiple llvm modules. Specifically, I want to use scalar evolution on different modules while being able to refer to the results across all modules thus processed. Ideally I don't want to do it as an LTO pass -- I don't know which modules I need to check at the time the program starts running. My current attempt at

Attached 2012/2/8 Marcello Maggioni <hayarms at gmail.com>: > Mmm, sorry, the patch I posted crashes if ExitBr is null (which it may > be ...) , this one should be ok (and passess all the ScalarEvolution > tests in LLVM): > > diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp > index daf7742..b10fab2 100644 > ---

Hello, I'm finding problems with BackEdgeTaken count calculation in even simple fortran loops with gfortran-4.6 + DragonEgg 3.0. Even for simple double loops like this one: program test2 integer i,j,k dimension k(100,100) do j=1,100 do i=1,100 k(i,j) = i enddo enddo write(*,*) k(1,30) end make the ScalarEvolution

Hi, I have problems to estimate the loop exit count of a simple loop with the ScalarEvolution class. simple loop: ...... int a = 0; for(int i; i < 10; ++i){ a = a + 1; }; ...... For the loop analyzation I use the ScalarEvolution class with the following initialization: ...... void analysis(Function* func) DominatorTree DT = DominatorTree(); DT.recalculate(*func);

Well, it wasn't intended as a "real" patch to be included , but more as a "proof of concept" for a solution. Do you think it is a valid solution and I'm correct in my assumption? If so then I'll clean up the patch and attach a testcase for inclusion. Thanks! Marcello 2012/2/9 Nick Lewycky <nlewycky at google.com>: > Your patch should include a testcase,

Mmm, sorry, the patch I posted crashes if ExitBr is null (which it may be ...) , this one should be ok (and passess all the ScalarEvolution tests in LLVM): diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp index daf7742..b10fab2 100644 --- a/lib/Analysis/ScalarEvolution.cpp +++ b/lib/Analysis/ScalarEvolution.cpp @@ -4293,9 +4293,15 @@

Your patch should include a testcase, see test/Analysis/ScalarEvolution for examples. "BranchInst* " should be "BranchInst *". You should have spaces after the // in your comments. One of the comment lines isn't indented properly. Nick On 8 February 2012 12:05, Marcello Maggioni <hayarms at gmail.com> wrote: > Attached > > 2012/2/8 Marcello Maggioni

This is the .ll for that graph (attached). I think I understand what you are saying. This particular testcase returns CNC not because the exit block doesn't have a unique predecessor, but because the unique predecessor (the inner loop block) has a successor that is inside the loop (in this case itself, because it's the inner loop block). That doesn't change, anyway, the assuption that

On 8 February 2012 15:50, Marcello Maggioni <hayarms at gmail.com> wrote: > Well, it wasn't intended as a "real" patch to be included , but more > as a "proof of concept" for a solution. Do you think it is a valid > solution and I'm correct in my assumption? If so then I'll clean up > the patch and attach a testcase for inclusion. > I'm

This is instead a very simple (handmade) test case that triggers the problem (attached) Also a more conforming patch has been attached 2012/2/9 Marcello Maggioni <hayarms at gmail.com>: > This is the .ll for that graph (attached). I think I understand what > you are saying. > This particular testcase returns CNC not because the exit block > doesn't have a unique predecessor,

Hi Sanjoy, Thank you for looking into this! Yes, your patch does fix my larger test case too. My algorithm gets double performance improvement with the patch, as the loop now has a smaller instruction set and succeeds to unroll w/o any extra #pragma's. I also ran the LLVM tests against the patch. There are 6 new failures: Analysis/LoopAccessAnalysis/number-of-memchecks.ll

FInally I had the time to complete everything up. Now I included the test case in the patch and the testcase runs with the LLVM tests system. 2012/2/9 Marcello Maggioni <hayarms at gmail.com>: > This is instead a very simple (handmade) test case that triggers the > problem (attached) > Also a more conforming patch has been attached > > 2012/2/9 Marcello Maggioni <hayarms

Hi, I'm working on a bug somewhere between SCEV and IndVarSimplify, which tacks an unwanted "nuw" onto an "add i32 %whatever, -1" (which actually almost certainly will overflow), leading ultimately to an infinite loop. A fuller description and test-case is at the end for anyone interested. The issue seems to be with ScalarEvolution's attempts to cache SCEV objects,

Guys, What I want to do is to hack global opt pass, which needs ScalarEvolution analysis. However opt crashed saying "opt: /home/xchen/llvm/include/llvm/PassAnalysisSupport.h:242: AnalysisType& llvm::Pass::getAnalysisID(const void*, llvm::Function&) [with AnalysisType = llvm::ScalarEvolution]: Assertion `ResultPass && "Unable to find requested analysis info"'

Hi, Both LazyValueInfo and ScalarEvolution can calculate a constant range for an LLVM Value. I found that some times they do not agree, may be I interpreted them incorrectly For example in the following IR: bb85: ; preds = %bb85, %bb73 %tmp86 = phi i32 [ 1, %bb73 ], [ %tmp95, %bb85 ] %tmp95 = add nsw i32 %tmp86, 1 %tmp96 = icmp slt i32 %tmp95,

> 1. Callers are expected to not engage in speculation. ScalarEvolution > itself must only create expressions it knows hold in all cases. This is correct. There is some more relevant text in ScalarEvolution::isSCEVExprNeverPoison. And you're right, this is quite restrictive. > Long term, I think that it would be cleaner to rework this so that all of the SCEV's are immutable

Hello all, I’m pretty new to LLVM. I'm writing a pass for loop optimization. I clone and rearrange loops, setting the cloned loop as the original loop’s parent. This can be done multiple times, until there is no more work to do. The trouble is, after the first time I do this, the cloned loop's SCEVs become unknown types when they should be AddRecExpr. If I re-run the whole pass on the

Dear All, Is the following patch to ScalarEvolution correct? It seems that without it, the enclosing for loop could skip over SCEVAddRecExpr's in the Ops[] array. -- John T. -------------- next part -------------- An embedded and charset-unspecified text was scrubbed... Name: scpatch URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20080222/3ff8edd7/attachment.ksh>

On 08/12/2010 09:41 PM, Douglas do Couto Teixeira wrote: > Dear guys, > > I am having problems to obtain good information from the LoopInfo. > I am always getting a trip count of 0, even though I am clearly passing > a loop with a constant bound. I am using this pass below: Hi, I would propose to first check if the trip count is calculated correctly. I would do this with opt