similar to: RFC: Devirtualization v2

> On Mar 19, 2018, at 7:27 PM, Piotr Padlewski via cfe-dev <cfe-dev at lists.llvm.org> wrote: > > Hi folks, > > here is a link to the proposal that we've been working on lately: > https://docs.google.com/document/d/16GVtCpzK8sIHNc2qZz6RN8amICNBtvjWUod2SujZVEo/edit?usp=sharing

Hi John, 2018-03-28 23:23 GMT+02:00 John McCall <rjmccall at apple.com>: > > > On Mar 19, 2018, at 7:27 PM, Piotr Padlewski via cfe-dev < > cfe-dev at lists.llvm.org> wrote: > > Hi folks, > > here is a link to the proposal that we've been working on lately: > https://docs.google.com/document/d/16GVtCpzK8sIHNc2qZz6RN8am >

Hi folks, please check out our RFC: Supported Optimizations attribute https://docs.google.com/document/d/1s0n-JVaSNML1Z9SCZVg2bgisxswIJAK2Tp9DahucW10/edit?usp=sharing Pasting it here for the record: RFC: supported_optimizations attribute Piotr Padlewski - piotr.padlewski at gmail.com Krzysztof Pszeniczny - kpszeniczny at google.com December 2018 Introduction Sometimes a possible class of

> On Mar 29, 2018, at 9:12 AM, Piotr Padlewski <piotr.padlewski at gmail.com> wrote: > 2018-03-28 23:23 GMT+02:00 John McCall <rjmccall at apple.com <mailto:rjmccall at apple.com>>: >> On Mar 19, 2018, at 7:27 PM, Piotr Padlewski via cfe-dev <cfe-dev at lists.llvm.org <mailto:cfe-dev at lists.llvm.org>> wrote: >> Note that adding calls to strip and

2018-03-29 18:01 GMT+02:00 John McCall <rjmccall at apple.com>: > On Mar 29, 2018, at 9:12 AM, Piotr Padlewski <piotr.padlewski at gmail.com> > wrote: > 2018-03-28 23:23 GMT+02:00 John McCall <rjmccall at apple.com>: >> >> On Mar 19, 2018, at 7:27 PM, Piotr Padlewski via cfe-dev < >> cfe-dev at lists.llvm.org> wrote: >> *Note that adding

On Sat, Jul 25, 2015 at 12:39 PM, Hal Finkel <hfinkel at anl.gov> wrote: > Hi Piotr, > > Thanks for posting this! First, a question. When you say, regarding i8* > @llvm.invariant.group.barrier(i8*): > > "Required to handle destructors, placement new and std::launder. Call of > this function will be put on the end of each of this functions" > > I

Hi Piotr, Thanks for posting this! First, a question. When you say, regarding i8* @llvm.invariant.group.barrier(i8*): "Required to handle destructors, placement new and std::launder. Call of this function will be put on the end of each of this functions" I completely understand placement new and std::launder. I don't understand destructors, could you explain? Also, am I correct

Sounds like it works! Basically, adding these extra strip.invariant.group calls before pointer comparisons breaks the transform that was problematic. Presumably, clang would only strip invariant groups from pointers to dynamic types before casting them or using them in a comparison, so that the value equivalence optimization still works in the general case. The proposal trades value equivalence

śr., 5 gru 2018 o 00:22 John McCall via cfe-dev <cfe-dev at lists.llvm.org> napisał(a): > On 4 Dec 2018, at 17:50, Philip Reames wrote: > > Skimming along, apologies if I'm repeating something which already got > said. > > If I understand this correctly, the basic problem we're trying to solve is > to use a local hint (the invariant.group) to make a global

Hi folks, this summer I will work with Richard Smith on clang devirtualization. Check out our proposal: https://docs.google.com/document/d/1f2SGa4TIPuBGm6y6YO768GrQsA8awNfGEJSBFukLhYA/edit?usp=sharing And modified LangRef http://reviews.llvm.org/D11399 You can also check out previous disscussion that was started before our proposal was ready -

> On Mar 30, 2018, at 10:36 AM, Piotr Padlewski <piotr.padlewski at gmail.com> wrote: > 2018-03-29 18:01 GMT+02:00 John McCall <rjmccall at apple.com <mailto:rjmccall at apple.com>>: >> On Mar 29, 2018, at 9:12 AM, Piotr Padlewski <piotr.padlewski at gmail.com <mailto:piotr.padlewski at gmail.com>> wrote: >> 2018-03-28 23:23 GMT+02:00 John McCall

On Wed, Oct 13, 2010 at 12:45 AM, Nick Lewycky <nicholas at mxc.ca> wrote: > Kenneth Uildriks wrote: >>> >>> You're right, I hadn't thought this through. The whole point of making >>> them >>> local is to say that "I'm sure these callees won't modify that memory" >>> regardless of what functions actually get called,

Kenneth Uildriks wrote: >> You're right, I hadn't thought this through. The whole point of making them >> local is to say that "I'm sure these callees won't modify that memory" >> regardless of what functions actually get called, even indirectly. We can't >> know that they won't modify the vptr in advance, so invariant doesn't work

> You're right, I hadn't thought this through. The whole point of making them > local is to say that "I'm sure these callees won't modify that memory" > regardless of what functions actually get called, even indirectly. We can't > know that they won't modify the vptr in advance, so invariant doesn't work > here. Making it non-local just means

On Oct 13, 2010, at 4:35 AM, Kenneth Uildriks wrote: > On Wed, Oct 13, 2010 at 12:45 AM, Nick Lewycky <nicholas at mxc.ca> wrote: >> Kenneth Uildriks wrote: >>>> >>>> You're right, I hadn't thought this through. The whole point of making >>>> them >>>> local is to say that "I'm sure these callees won't modify

Hi all, I would like to propose a new way clang would decorate vtable loads in order to handle devirtualization better. I've added *llvm-dev* also, because this can start a discussion about changing invariant.group to just invariant. PDF version of this RFC can be found here: https://drive.google.com/file/d/0B72TmzNsY6Z8ZmpOUnB5dDZfSFU/view?usp=sharing Background: Initial old design:

Kenneth Uildriks wrote: > On Wed, Oct 13, 2010 at 12:45 AM, Nick Lewycky<nicholas at mxc.ca> wrote: >> Kenneth Uildriks wrote: >>>> >>>> You're right, I hadn't thought this through. The whole point of making >>>> them >>>> local is to say that "I'm sure these callees won't modify that memory" >>>>

On Wed, Oct 13, 2010 at 11:16 PM, Nick Lewycky <nicholas at mxc.ca> wrote: > Kenneth Uildriks wrote: >> >> On Wed, Oct 13, 2010 at 12:45 AM, Nick Lewycky<nicholas at mxc.ca>  wrote: >>> >>> Kenneth Uildriks wrote: >>>>> >>>>> You're right, I hadn't thought this through. The whole point of making >>>>>

Hi Piotr, I think makes sense. Modulo bitcasts, the invariant is identified by a particular pointer SSA value. Given that you can't sensibly have two nonequivalent invariants associated with the same pointer SSA value simultaneously, there's no need to also identify the invariant with a metadata string as well. When we need a new "identifier" for the pointed-to value, we

2017-04-01 15:59 GMT+02:00 Piotr Padlewski <piotr.padlewski at gmail.com>: > > > 2017-03-31 23:20 GMT+02:00 Sanjoy Das <sanjoy at playingwithpointers.com>: > >> Hi Piotr, >> >> On March 31, 2017 at 1:07:12 PM, Piotr Padlewski >> (piotr.padlewski at gmail.com) wrote: >> > [snip] >> > Do I understand it correctly, that it is legal to