search for: scevconstants

...correct length? I've seen you create an SCEV with value 2. Should I do that each time? I'm working on writing out Banerjee and Wolfe's exact SIV test and the hardest part seems to be specifying the type of all the various numbers. I'm manipulating many constants (0, 1, and various SCEVConstants) and doing arithmetic with them. I assume it's better (quicker, smaller) to use APInts for everything. Any general advice? Thanks, Preston -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20120416/c782ddd9...

Hi, I'm new to ScalarEvolution and wanted to explore its capabilities. I have following few questions: 1) How to compare SCEV expressions. I have a situation to compare two SCEV to find the min among them. Found an existing function(getMinFromExprs) in LoopAccessAnalysis which compares two SCEVs. getMinFromExprs function finds the diff between two SCEV's and then checks for the negative

Hi Ashutosh, On Wed, May 9, 2018 at 3:28 AM, Nema, Ashutosh via llvm-dev <llvm-dev at lists.llvm.org> wrote: > I’m new to ScalarEvolution and wanted to explore its capabilities. > > I have following few questions: > > 1) How to compare SCEV expressions. > > I have a situation to compare two SCEV to find the min among them. > > Found an existing

Thanks Sanjoy, I'll look into this. -----Original Message----- From: Sanjoy Das [mailto:sanjoy at playingwithpointers.com] Sent: Thursday, May 10, 2018 8:07 AM To: Nema, Ashutosh <Ashutosh.Nema at amd.com> Cc: llvm-dev at lists.llvm.org Subject: Re: [llvm-dev] ScalarEvolution questions Hi Ashutosh, On Wed, May 9, 2018 at 3:28 AM, Nema, Ashutosh via llvm-dev <llvm-dev at

I've been doing some digging in this area (scev, wrapping arithmetic), learning as much as I can, and have reached a point where I'm fairly confused about the semantics of nuw in scalar evolution expressions. Consider the following program: define void @foo(i32 %begin) { entry: br label %loop loop: %idx = phi i32 [ %begin, %entry ], [ %idx.dec, %loop ] %idx.dec = sub nuw i32

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 where trying to find min between two SCEVs under an extra condition. “isImpliedCond” is not helping for below case, may be I’m missing something:

Is there a document describing the guts of SCEV anywhere? I have a simple question. When looking at a linear SCEVAddRecExpr with a constant step recurrence (that is, getStepRecurrence returns SCEVConstant), is the constant in terms of bytes or in terms of "index," in that the byte offset is calculated by taking the step and multiplying it by the data size of any memory operation its

The Problem? Nowaday, SCEV called "Scalar Evolution" does only evolate instructions that has predictable operand, Constant-Based operand. such as that can evolute as a constant. otherwise we couldn't evolate it as SCEV node, evolated as SCEVUnknown. important thing that we remember is, we do not use SCEV only for Loop Deletion, which that doesn't really needed on nature loops

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

On 11/12/2011 12:11 AM, Hal Finkel wrote: > On Fri, 2011-11-11 at 23:55 +0100, Tobias Grosser wrote: >> On 11/11/2011 11:36 PM, Hal Finkel wrote: >>> On Thu, 2011-11-10 at 23:07 +0100, Tobias Grosser wrote: >>>> On 11/08/2011 11:29 PM, Hal Finkel wrote: Talking about this I >>>> looked again into ScalarEvolution. >>>> >>>> To

I now understand that IndVarSimplify.cpp is capable of reproducing array references when the pointer initialization from the array address is found inside the immediately enclosing loop, such that in the following code: int A[20000], B[100], Z; int main() { int i, j, *a, *b; for ( a = &A[0], i = 0; i != 200; i++ ) for ( b = &B[0], j = 0; j != 100; j++

On Fri, 2011-11-11 at 23:55 +0100, Tobias Grosser wrote: > On 11/11/2011 11:36 PM, Hal Finkel wrote: > > On Thu, 2011-11-10 at 23:07 +0100, Tobias Grosser wrote: > >> On 11/08/2011 11:29 PM, Hal Finkel wrote: > >> Talking about this I looked again into ScalarEvolution. > >> > >> To analyze a load, you would do: > >> > >> LoadInst *Load

I have a few questions regarding cost calculation in loop strength reduction. 1. Ignoring LSR uses of kind ICmpZero. These usually come from the loop latch conditions. On Hexagon most loops that would contain such a LSR use are going to be converted to hardware loops and the entire check will disappear. There is no need to analyze these cases in LSR. In fact, completely ignoring them improves

Hi, > Is there a document describing the guts of SCEV anywhere? If you're looking for theoretical background of SCEV (chains of recurrences algebra), you may take a look at this article: http://citeseer.ist.psu.edu/vanengelen00symbolic.html I'm not aware of any LLVM-specific document describing SCEV. > I have a simple question. When looking at a linear SCEVAddRecExpr > with a

Tobias, I've attached the latest version of my autovectorization patch. I was able to add support for using the ScalarEvolution analysis for load/store pairing (thanks for your help!). This led to a modest performance increase and a modest compile-time increase. This version also has a cutoff as you suggested (although the default value is set high (4000 instructions between pairs) because

On 05/30/2018 06:04 AM, Siddharth Bhat via llvm-dev wrote: > You can run SCEV which will see through bitcasts and GEPs, so it > should give an expression of the form (base + offset) on the pointer > of the load. Specifically, you can use ScalarEvolution to subtract the expression for the base descriptor from the expression for the loaded pointer and see if the result is a SCEVConstant.

The enlosed patch for IndVarSimplify.cpp works even when the pointer increment is deeply nested wrt pointer initialization, but note that it needs to have loop structures preserved, as in the following: int A[3000000], B[20000], C[100], Z; volatile int I, J, K; int main() { int i, j, k, *a, *b, *c; for ( a = &A[0], i = 0; i != 300; i++ ) { I++;

Tobias, et al., Attached is the my autovectorization pass. I've fixed a bug that appears when using -bb-vectorize-aligned-only, fixed some 80-col violations, etc., and at least on x86_64, all test cases pass except for a few; and all of these failures look like instruction-selection bugs. For example: MultiSource/Applications/ClamAV - fails to compile shared_sha256.c with an error: error in

On Thu, 28 Jul 2005, Naftali Schwartz wrote: > I now understand that IndVarSimplify.cpp is capable of reproducing array > references when the pointer initialization from the array address is found > inside the immediately enclosing loop, such that in the following code: Ok. > int A[20000], B[100], Z; > int main() > { > int i, j, *a, *b; > for ( a =

Sent from my iPhone > On Nov 2, 2013, at 1:52 AM, Andrew Trick <atrick at apple.com> wrote: > > >> On Oct 31, 2013, at 6:06 AM, Hal Finkel <hfinkel at anl.gov> wrote: >> >> Hello, >> >> We currently generate suboptimal code for this loop: >> >> for (int i = 1; i < LEN; i++) { >> a[i] = a[0] + b[i]; >> } >>