similar to: [LLVMdev] [polly] Polly Loop info and LoopSimplify functionality

On 05/15/2013 07:08 PM, Sergei Larin wrote: > > Tobias, [..] > > ...or as always I might be missing a big picture here, and I appreciate if > you can explain the original intent. Hi Sergei, thanks for reporting this issue in so much detail. I am afraid there is no bigger story. For some reason the update of the LoopInfo was not included in the original patch of the code

In https://bugs.llvm.org/show_bug.cgi?id=38011 (see also https://reviews.llvm.org/D48721) a problem was revealed related to llvm.loop metadata. The fault was that clang added the !llvm.loop metadata to branches outside of the loop (not only the loop latch). That was not handled properly by some opt passes (simplifying cfg) since it ended up merging branch instructions with different !llvm.loop

I tried to manually assign each of 3 arrays a unique TBAA node. But it does not seem to help: alias analysis still considers arrays as may-alias, which most likely prevents the desired optimization. Below is the sample code with TBAA metadata inserted. Could you please suggest what might be wrong with it? Many thanks, - D. marcusmae at M17xR4:~/forge/llvm$ opt -time-passes -enable-tbaa -tbaa

----- Original Message ----- > From: "Sergei Larin" <slarin at codeaurora.org> > To: "Hal Finkel" <hfinkel at anl.gov> > Cc: llvmdev at cs.uiuc.edu > Sent: Friday, March 1, 2013 10:24:39 AM > Subject: Interesting post increment situation in DAG combiner > > Hal, (and everyone who might care about post increment generation)... Sergei, Perhaps

Hal, (and everyone who might care about post increment generation)... I have an interesting question/observation. Consider this vector loop. void vec_add_const(unsigned N, short __attribute__ ((aligned (16))) *A, short __attribute__ ((aligned (16))) val) { unsigned i,j; for (i=0; i<N; i++) { for (j=0; j<N; j++) { A[i*N+j] += val; } } } The

Hal, Here is my patch for the post inc case. I think it is symmetrically applicable to the pre-inc, but I have not tested it for that. I think you can clearly see my intent here - I simply select the "latest" candidate when multiple are available. Who else might be interested in this? Sergei --- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The

Hi, I have a general question on LoopUnswtich pass. Consider the following IR snippet: define i32 @test(i1 %cond) { br label %loop_begin loop_begin: br i1 %cond, label %loop_body, label %loop_exit loop_body: br label %do_something do_something: call void @some_func() noreturn nounwind br label %loop_begin loop_exit: ret i32 0 } declare void @some_func() noreturn After running

Hi, The following arbitrary example makes the code generators to get stuck (llvmc won't return from command line, Jit won't return from function call) Basically it is a CFG with circles, (the function will return by comparing a branch counter to a threshold on runtime - see the "Brancher" blocks below) Any idea what goes wrong? Is it a bug in llvm ? ; ModuleID =

Mmm, this code seems to kill polly: #include <stdio.h> #include <stdlib.h> int main() { char *B; int i,j,k,h; const int x = 0, y=0; B = (char *)malloc(sizeof(char)*1024*1024); for (i = 1; i < 1024; i++) for (j = 1; j < 1024; j++) { if (i+j > 1000) B[j] = i; } printf("Random Value: %d", B[rand() % 1024*1024]); return 0; } running: opt

On 09/30/2013 04:11 AM, Star Tan wrote: > At 2013-09-25 18:03:18,"Tobias Grosser" <tobias at grosser.es> wrote:> >> I think this is too early, as most of the canonicalization is not yet >> done. We probably don't need to investigate this bug immediately, but >> it would be nice if we could make it reproducible without your changes >> to polly. For

Hello, LoopSimplify try to separate a loop with multiple backedges into a nested loop (an outer loop and an inner loop). Naturally, this kind of a loop corresponds to a single loop in source code. I can see this could be useful for cases described in the comments in lib/Transforms/Utils/LoopSimplify.cpp, which looks like a corner case. For most cases, how does this help ? Junjie

See http://llvm.org/docs/GettingStarted.html#brokengcc and then try building with something OTHER than GCC 4.1.2 . ----- Original Message ---- > From: Nick Johnson <npjohnso at cs.princeton.edu> > To: LLVM Developers Mailing List <llvmdev at cs.uiuc.edu> > Sent: Monday, May 11, 2009 3:01:12 PM > Subject: [LLVMdev] Pass Manager hangs with CallGraph and LoopSimplify >

On Fri, Oct 13, 2017 at 5:13 PM, Michael Kruse via llvm-dev < llvm-dev at lists.llvm.org> wrote: > 2017-10-14 1:29 GMT+02:00 Saito, Hideki via llvm-dev < > llvm-dev at lists.llvm.org>: > > I'm also sorry that I'm not commenting on the main part of your RFC in > this reply. I just want to focus on > > one thing here. > > > >

I will try to reduce a test case for the regression I found and will update. Thanks, Balaram From: Friedman, Eli [mailto:efriedma at codeaurora.org] Sent: Friday, June 30, 2017 2:54 PM To: Balaram Makam <bmakam at codeaurora.org>; llvm-dev at lists.llvm.org Subject: Re: [llvm-dev] LoopSimplify pass prevents loop unrolling On 6/30/2017 11:38 AM, Balaram Makam wrote: Thanks Eli,

Hello, I have discovered a situation in which the pass manager will infinite loop. The minimal test case is below this message. The required structure of these passes is; Before requires CallGraph After requires LoopSimplify and Before I can observe this through opt: opt -load ./libBug.so -after input.bc -o output.bc I built my copy of llvm from svn revision 68820 using gcc 4.1.2 Any

Hi All, In the attached test case there, is an unnested loop with 2 iterations. The loop latch block is terminated by an unconditional branch, so simplifycfg folds the almost empty latch block into its predecessor which is the loop header. This results in an additional backedge in the CFG, so when LoopRotate pass is called it canonicalizes the loop into a nested loop. However, now the loop

I am reading the code for exit block transformation in loop simplify. I do not fully understand how exit blocks with out-of-loop dominators are transformed. In SplitLandingPadPredecessors, all the in-the-loop predecessors of the exits block are grouped and given to the .loopexit basic block and the out-of-loop predecessors are grouped and given to the .nonloopexit basic block. the .loopexit

On 6/30/2017 11:38 AM, Balaram Makam wrote: > > Thanks Eli, > > I was looking at this code which keeps track of loop headers but is > checking if the destination of branch is a loop header sufficient? > This prevents merging empty preheaders into the loop headers as well. > There isn't really any reason to collapse preheaders anyway; LoopSimplify will recreate them,

On 6/30/2017 7:48 AM, Balaram Makam via llvm-dev wrote: > > Edit. Predecessor -> successor. > > *From:* llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] *On Behalf > Of *Balaram Makam via llvm-dev > *Sent:* Friday, June 30, 2017 10:47 AM > *To:* llvm-dev at lists.llvm.org > *Subject:* [llvm-dev] LoopSimplify pass prevents loop unrolling > > Hi All, > >

At 2013-09-25 18:03:18,"Tobias Grosser" <tobias at grosser.es> wrote:> >I think this is too early, as most of the canonicalization is not yet  >done. We probably don't need to investigate this bug immediately, but >it would be nice if we could make it reproducible without your changes  >to polly. For this please run the command with -debug-pass=Arguments