similar to: [LLVMdev] Naryreassociate vs reassociate

Hi Daniel, I presume you mean, instead of assigning function arguments distinct ranks ( http://llvm.org/docs/doxygen/html/Reassociate_8cpp_source.html#l00282), we should group function arguments in favor of existing pairings. You are not suggesting discarding the entire ranking system, right? I'll look into how that works on my benchmarks. AFAIK, we encountered some cases that seem beyond

On Tue, May 5, 2015 at 10:20 AM, Jingyue Wu <jingyue at google.com> wrote: > Hi Daniel, > > I presume you mean, instead of assigning function arguments distinct ranks > (http://llvm.org/docs/doxygen/html/Reassociate_8cpp_source.html#l00282), we > should group function arguments in favor of existing pairings. Existing = pairings reassociate already chose before *not* existing

On Tue, May 5, 2015 at 10:31 AM, Daniel Berlin <dberlin at dberlin.org> wrote: > On Tue, May 5, 2015 at 10:20 AM, Jingyue Wu <jingyue at google.com> wrote: > > Hi Daniel, > > > > I presume you mean, instead of assigning function arguments distinct > ranks > > (http://llvm.org/docs/doxygen/html/Reassociate_8cpp_source.html#l00282), > we > > should

Hi Andrew, Shuxin, Thanks for the explanation about 'Reassociate'. The problem is indeed that one of the variables, becomes loop invariant after some of the loop transformations. > -----Original Message----- > From: Andrew Trick [mailto:atrick at apple.com] [...] > Right. Reassociate ranks expressions by their order in the IR, so shouldn't > make matters worse, but it

On Apr 23, 2013, at 10:37 AM, Shuxin Yang <shuxin.llvm at gmail.com> wrote: > As far as I can understand of the code, the Reassociate tries to achieve this result by its "ranking" mechanism. > > If it dose not, it is not hard to achieve this result, just restructure the expression in a way such that > the earlier definition of the sub-expression is permute earlier in

Hi, I encountered some bugs in Reassociate [1] where we are hitting some assertions: assert(!Duplicates.count(Factor) && "Shouldn't have two constant factors, missed a canonicalize"); assert(NumAddedValues > 1 && "Each occurrence should contribute a value”); My understanding is that these assertions enforce that when processing an

It's an interesting problem. The best stuff I've seen published is by Cooper, Eckhart, & Kennedy, in PACT '08. Cooper gives a nice intro in one of his lectures: http://www.cs.rice.edu/~keith/512/2012/Lectures/26ReassocII-1up.pdf I can't tell, quickly, what's going on in Reassociate; as usual, the documentation resolutely avoids giving any credit for the ideas. Why is that?

On Apr 25, 2013, at 10:51 AM, Preston Briggs <preston.briggs at gmail.com> wrote: > It's an interesting problem. > The best stuff I've seen published is by Cooper, Eckhart, & Kennedy, in PACT '08. > Cooper gives a nice intro in one of his lectures: http://www.cs.rice.edu/~keith/512/2012/Lectures/26ReassocII-1up.pdf > I can't tell, quickly, what's going on

As far as I can understand of the code, the Reassociate tries to achieve this result by its "ranking" mechanism. If it dose not, it is not hard to achieve this result, just restructure the expression in a way such that the earlier definition of the sub-expression is permute earlier in the resulting expr. e.g. outer-loop1 x= outer-loop2 y =

>> On Feb 2, 2015, at 11:12 AM, Mehdi Amini <mehdi.amini at apple.com> wrote: >> >> Hi, >> >> I encountered some bugs in Reassociate [1] where we are hitting some >> assertions: >> >> assert(!Duplicates.count(Factor) && >> "Shouldn't have two constant factors, missed a >> canonicalize");

> Hi Chad, > > Thanks for you answer. > >> On Feb 4, 2015, at 11:22 AM, Chad Rosier <mcrosier at codeaurora.org> >> wrote: >> >>>> On Feb 2, 2015, at 11:12 AM, Mehdi Amini <mehdi.amini at apple.com> >>>> wrote: >>>> >>>> Hi, >>>> >>>> I encountered some bugs in Reassociate [1] where we

Hi, I am investigating a performance degradation between llvm-3.1 and llvm-3.2 (Note: current top-of-tree shows a similar degradation) One issue I see is the following: - 'loop invariant code motion' seems to be depending on the result of the 'reassociate expression' pass: In the samples below I observer the following behavior: Both start with the same expression: %add = add

When playing around with reassociate I noticed a seemingly obvious optimization that was not getting done anywhere in llvm… nor in gcc or ICC. Consider the following trivial function: void foo(int a, int b, int c, int d, int e, int *res) { res[0] = (e * a) * d; res[1] = (e * b) * d; res[2] = (e * c) * d; } This function can be optimized down to 4 multiplies instead of 6 by reassociating

Owen/All, I've been working on adding support for reassociation with unsafe math (see: http://reviews.llvm.org/D4129). Do you know if this change, r156323, is still necessary? Specifically, do we need the reassociation pass to canonicalize FP operands for CSE to work effectively? This kinda scares me if it does! :( Side note: Without this canonicalization, I did see a 3% regression in Mesa

On Fri, Mar 13, 2015 at 10:16 AM Mark Heffernan <meheff at google.com> wrote: > On Thu, Mar 12, 2015 at 2:34 PM, Hal Finkel <hfinkel at anl.gov> wrote: > >> It is not clear to me at all that preventing the merging is the right >> solution. There are a large number of analysis, including alias analysis, >> and optimizations that use GetUnderlyingObject, and

Hello, We've run across the following missed optimization: in the attached loop (addind.c/addind-opt.ll) there's a lookup into an array (V) using an indirect index (coming from another array, WI[k]) offset by a loop- invariant base (l). The full addressing expression can be reassociated so that we add the offset l to V's base first, and then add the indirect part. This makes

On Fri, Jan 30, 2009 at 3:03 PM, Stefanus Du Toit <stefanus.dutoit at rapidmind.com> wrote: > The computation of %base then becomes loop-invariant and can be lifted out. > > What's the best way to add this optimization to LLVM? Probably the best place is LICM itself... only loop transformations are aware whether something is loop-invariant. Although, I'm not completely

----- Original Message ----- > From: "Jingyue Wu" <jingyue at google.com> > To: "Daniel Berlin" <dberlin at dberlin.org>, "Mark Heffernan" <meheff at google.com>, "Hal Finkel" <hfinkel at anl.gov> > Cc: "LLVM Developers Mailing List" <llvmdev at cs.uiuc.edu> > Sent: Friday, March 13, 2015 1:31:59 PM >

On Thu, Apr 25, 2013 at 9:18 AM, Arnold Schwaighofer < aschwaighofer at apple.com> wrote: > > On Apr 25, 2013, at 10:51 AM, Preston Briggs <preston.briggs at gmail.com> wrote: > > > It's an interesting problem. > > The best stuff I've seen published is by Cooper, Eckhart, & Kennedy, in PACT '08. > > Cooper gives a nice intro in one of his

There are at least 3 active proposals to add reassociative optimizations in IR: [1] D41574 <https://reviews.llvm.org/D41574>- a new pass for reassociation/factoring [2] D46336 <https://reviews.llvm.org/D46336> - enhance -instcombine to do more reassociation/factoring [3] D45842 <https://reviews.llvm.org/D45842> - add to the existing -reassociate pass to enable factoring