search for: d41574

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...

...want? If not, could there be conflicts among different reassociation orders depending on what folding we want? On Tue, May 8, 2018 at 9:19 AM Sanjay Patel <spatel at rotateright.com> wrote: > 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...

I mentioned this earlier in the thread - I would like to see something like D41574 in the optimizer. It's optimizing code that no other pass does currently, and I don't see any other near-term proposal that gets us those optimizations. Omer, can you rebase that to trunk? I think a header has moved, so it doesn't build as-is. I'd like to know if it can catch the c...

...t parts of the compiler, but it would be nice to at least be self consistent. > > > On Tue, May 8, 2018 at 9:19 AM Sanjay Patel <spatel at rotateright.com> > wrote: > >> 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 &...

...sociate passes to >>>> fold different reassociative patterns? >>>> >>>> A longer version: If Sanjay wants a particular reassociative pattern to >>>> be folded (D45842), Omer wants another particular reassociative pattern >>>> to be folded (D41574), and I want yet another ​particular reassociative >>>> pattern to be folded (D46336), would we potentially need three >>>> different reassociate passes with each combined with instcombine, rather >>>> than just one that may be able to somehow handle those cases...

...than some other pass? Or not all as an IR optimization? A dedicated optimization pass that looks for and makes factoring/distribution folds to eliminate instructions seems like it would solve the problems that I'm seeing. Ie, I'm leaning towards the proposal here: https://reviews.llvm.org/D41574 But I'd make it less "weak". :) Ideally, that allows removing duplicate functionality from instcombine, but I'm guessing that it will take a lot of work to cut that cord without causing regressions. Note that instcombine even has a specialized reassociation pass-within-a-pass for...

...d be nice to at least be self consistent. > >> >> >> On Tue, May 8, 2018 at 9:19 AM Sanjay Patel <spatel at rotateright.com> >> wrote: >> >>> 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 t...

> On May 8, 2018, at 9:50 AM, Daniel Berlin via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > 1. The reassociate pass that exists right now was *originally* (AFAIK) written to enable CSE/GVN to do better. Agreed. The original mindset included a (naive) belief that going with a canonical form was better than teaching redundancy elimination to handle abstractions (as a matter

...s variations. > > > ​ Let me try one more time :) May we need multiple reassociate passes to fold different reassociative patterns? A longer version: If Sanjay wants a particular reassociative pattern to be folded (D45842), Omer wants another particular reassociative pattern to be folded (D41574), and I want yet another ​particular reassociative pattern to be folded (D46336), would we potentially need three different reassociate passes with each combined with instcombine, rather than just one that may be able to somehow handle those cases in one shot, (assuming we don't want to put tho...

...​ > Let me try one more time :) May we need multiple reassociate passes to > fold different reassociative patterns? > > A longer version: If Sanjay wants a particular reassociative pattern to be > folded (D45842), Omer wants another particular reassociative pattern to > be folded (D41574), and I want yet another ​particular reassociative > pattern to be folded (D46336), would we potentially need three > different reassociate passes with each combined with instcombine, rather > than just one that may be able to somehow handle those cases in one shot, > (assuming we don...

...e need multiple reassociate passes to >>> fold different reassociative patterns? >>> >>> A longer version: If Sanjay wants a particular reassociative pattern to >>> be folded (D45842), Omer wants another particular reassociative pattern >>> to be folded (D41574), and I want yet another ​particular reassociative >>> pattern to be folded (D46336), would we potentially need three >>> different reassociate passes with each combined with instcombine, rather >>> than just one that may be able to somehow handle those cases in one >&...

On Wed, May 9, 2018 at 10:39 AM, Hiroshi Yamauchi <yamauchi at google.com> wrote: > > > On Tue, May 8, 2018 at 11:15 AM Daniel Berlin <dberlin at dberlin.org> wrote: > >> >> >> On Tue, May 8, 2018 at 10:38 AM, Hiroshi Yamauchi via llvm-dev < >> llvm-dev at lists.llvm.org> wrote: >> >>> ( >>> ​I came across this issue in

...reassociate passes to fold different reassociative patterns? > > A longer version: If Sanjay wants a particular > reassociative pattern to be folded (D45842), Omer wants > another particular reassociative pattern to be folded > (D41574), and I want yet another ​particular reassociative > pattern to be folded (D46336), would we potentially need > three different reassociate passes with each combined with > instcombine, rather than just one that may be able to > somehow ha...

...e more time :) May we need multiple reassociate passes to >> fold different reassociative patterns? >> >> A longer version: If Sanjay wants a particular reassociative pattern to >> be folded (D45842), Omer wants another particular reassociative pattern >> to be folded (D41574), and I want yet another ​particular reassociative >> pattern to be folded (D46336), would we potentially need three >> different reassociate passes with each combined with instcombine, rather >> than just one that may be able to somehow handle those cases in one >> shot, (a...