similar to: [LLVMdev] On semantics of add instruction - nsw,nuw flags

On Wed, Jul 23, 2014 at 4:06 PM, Rekha R <rekharamapai at nitc.ac.in> wrote: > Ok. Got it. > > If *add nsw* overflows, this results in undefined value. > But then *add* on same arguments results in well-defined value. > > Hence treating first one as redundant based on the second is acceptable. > But vice versa is not. > If they are in different code paths, sure.

IMHO; On undefined behaviour we can do whatever we want. If the "add nsw" overflows this would lead to undefined behaviour. Therefore we can assume that "add", with the same arguments will not overflow. On Wed, Jul 23, 2014 at 3:32 PM, Tim Northover <t.p.northover at gmail.com> wrote: > On 23 July 2014 06:25, Rekha R <rekharamapai at nitc.ac.in> wrote: >

> Then why does the Release Note say > " the operation is guaranteed to not overflow". It means that the person who wrote the IR has guaranteed that there's no overflow (by some means) so LLVM can assume it during optimisation. This guarantee might come from doing explicit checks before executing the add/sub; or perhaps from performing the operation after a sext so that the

Thank you David for prompt reply. I tried with SmallVector. I inserted elements with push_back(). But when I retrieve elements using pop_back_val the elements are returned in reverse order of insertion (I mean like LIFO order). I need this to be FIFO order. How to achieve that? Regards, Rekha On Sun, Nov 3, 2013 at 8:31 PM, David Blaikie <dblaikie at gmail.com> wrote: > If you

On Sun, Nov 3, 2013 at 7:38 AM, Rekha R <rekharamapai at nitc.ac.in> wrote: > Thank you David for prompt reply. > > I tried with SmallVector. I inserted elements with push_back(). > But when I retrieve elements using pop_back_val the elements are returned > in reverse order of insertion (I mean like LIFO order). > I need this to be FIFO order. How to achieve that? >

Hi, Thank you David. My question was from a machine independent code analyzer/optimizer perspective where types are of less importance. Hence I felt difficult to understand the IR with the types. Rekha On Mon, Oct 27, 2014 at 6:44 PM, David Chisnall <David.Chisnall at cl.cam.ac.uk > wrote: > On 27 Oct 2014, at 12:46, Rekha R <rekharamapai at nitc.ac.in> wrote: > > > Why

Hi, I am writing an analysis which requires creating worklist of basic blocks. The worklist should be in FIFO order. I checked SmallVector (and similar others) and found out this is working in LIFO order when I use the functions push_back and pop_back_val to insert and delete elements in the worklist. Can someone suggest an appropriate DS to implement my worklist. Note: I am not concerned about

Hi, I wrote a pass in LLVM and would like to test it on the programs in LLVM test-suite. To be specific, I would like to get the stats upon running my pass on these programs. What are the commands to run my pass on the test suite? -- Rekha -------------- next part -------------- An HTML attachment was scrubbed... URL:

Hi, I was trying to write a sample optimization pass in LLVM, by following instructions in LLVM doc for Writing a New Pass. But then ran into *make*issues. The issue is with having separate *source *and *build* directories. The LLVM doc for 'Getting Started' suggests keeping the two separate, but the 'Writing a new pass' doc assumes they are merged. Hence the *make *issue. I did

Hi, I am curious to know the design decision on why operands of LLVM IR instructions are type annotated. Why wasn't the C style of explicit declaration of variables (or values in LLVM context) followed by their uses model not adopted here? or may be even annotate the value (result of the Instruction) with type rather than annotating each operands on the Instruction? Just felt that by

If you don't care about efficiency you can push (or at least insert) at the front of a(small or otherwise) vector. On Nov 3, 2013 3:32 AM, "Rekha R" <rekharamapai at nitc.ac.in> wrote: > Hi, > > I am writing an analysis which requires creating worklist of basic blocks. > The worklist should be in FIFO order. I checked SmallVector (and similar > others) and found

Hi, I was studying the LLVM IR instruction set by analyzing how constructs in C language is getting converted to IR form. I found difficulty in finding C constructs which could generate Invoke, Resume, Unreachable, ExtractValue, InsertValue instructions. Can someone help me find some simple C code that generates these instructions in LLVM IR? -- Regards, Rekha -------------- next part

On Oct 3, 2013 11:47 PM, "Rekha R" <rekharamapai at nitc.ac.in> wrote: > > Hi, > > I was trying to write a sample optimization pass in LLVM, by following instructions in LLVM doc for Writing a New Pass. But then ran into make issues. The issue is with having separate source and build directories. The LLVM doc for 'Getting Started' suggests keeping the two

Hello, I am trying to figure out, what vrp propagation does in llvm. I tried this program: #include <stdio.h> int main() { int s = 0; int j = 0; for (int i = 0; i < 100; i++) { j = j+i+1; s+=j; } return (s+j); } And got this under optimized version ( I don't want everything to be eliminated) define i32 @main()

Hi, I am trying to implement Available Expressions data flow analysis. I created the following class (I am giving here code snippet.): namespace { typedef DenseMap<Expression, uint32_t> DMTy; //Expression is a class I defined. struct DataFlowValue { DMTy ExprMap; llvm::BitVector* DFV; // Functions operating on the data // bool operator==(const DataFlowValue V) const;

Hi, Can someone tell which algorithm is used for GVN in LLVM? -- Rekha -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20130928/ca06c78a/attachment.html>

On Mon, Nov 4, 2013 at 10:35 AM, Rekha R <rekharamapai at nitc.ac.in> wrote: > Hi, > > I am trying to implement Available Expressions data flow analysis. I created > the following class (I am giving here code snippet.): > > namespace { > typedef DenseMap<Expression, uint32_t> DMTy; //Expression is a class I > defined. > struct DataFlowValue { >

On Mon, Aug 7, 2017 at 2:14 AM, Anastasiya Ruzhanskaya via llvm-dev <llvm-dev at lists.llvm.org> wrote: > I am trying to print it like this (maybe here is smth wrong?) > > > LazyValueInfo &LV = getAnalysis<LazyValueInfoWrapperPass>().getLVI(); > DominatorTree &DT = > getAnalysis<DominatorTreeWrapperPass>().getDomTree(); > LV.printLVI(F,

Hi, I intend to write an optimization using LLVM. But before doing that I felt like understanding the tools. I wrote a hello world program to be compiled and executed. But then one of the tutorials suggested using Clang, an other said dragonegg, a third suggested using llvm-gcc. I am confused as to which one to use. Can some one help me in 1. What are the differences between these three? 2. Which

I am primarily interested in phi nodes and their induction variables, in ValueTracking file there is an analysis of them, but if the upper bound is inf, it is not working? 2017-08-07 11:41 GMT+02:00 Anastasiya Ruzhanskaya < anastasiya.ruzhanskaya at frtk.ru>: > So, it is not supported to determine by this instruction : %cmp = icmp slt > i32 %i.03, 99, > that %i.03 = phi i32 [ 0,