similar to: Optimizing memory allocation for custom allocators and non C code

> On Jan 4, 2016, at 9:55 AM, Amaury SECHET via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > > > 2016-01-04 18:21 GMT+01:00 Philip Reames <listmail at philipreames.com <mailto:listmail at philipreames.com>>: > On 01/04/2016 07:32 AM, Amaury SECHET wrote: >> After a bit more investigation, it turns out that because %0 is stored into %1 (after

2015-12-26 18:32 GMT+01:00 Philip Reames <listmail at philipreames.com>: > On 12/26/2015 02:17 AM, Amaury SECHET via llvm-dev wrote: > > I'm trying to fix that bug: https://llvm.org/bugs/show_bug.cgi?id=20049 > > It turns out this is the kind of optimization that I really need, as when > it isn't done, all kind of other optimizations opportunities down the road

On 01/04/2016 07:32 AM, Amaury SECHET wrote: > After a bit more investigation, it turns out that because %0 is stored > into %1 (after bitcast) and so %3 may have access to it and clobber it. Can you give a bit more context? I'm not sure which of the examples you're talking about. > > After a bit of thought, it is correct in the general case, but > definitively something

Explicitly re-adding a node to be processed doesn't work, because the processing order is canonical. 2017-05-22 11:39 GMT-07:00 Nirav Davé <niravd at google.com>: > You can always explicitly add D to the worklist when you make the > transformation with AddToWorklist. Presuambly this was the cause for your > infinite loop. > > -Nirav > > > On Mon, May 22, 2017 at

The root problem is that, when A gets modified, D doesn't get added back to the worklist. I could match the pattern on A, but the problem remains: when D gets modified, A do not get added back tot he worklist. I also considered ding several round of DAGCombine, but it is very easy to run into infinite loops, even with a fair amount of sanity checks. 2017-05-22 7:30 GMT-07:00 Nirav Davé

I'm trying to fix that bug: https://llvm.org/bugs/show_bug.cgi?id=20049 It turns out this is the kind of optimization that I really need, as when it isn't done, all kind of other optimizations opportunities down the road are not realized as they are not exposed. I have no idea where to start digging for this. I assume there is some kind of interaction between memory dependency and alias

I don't think that'd work, because it leaves all other backends broken. AFAICT, your transform is simply not a legal transform, with the way the ADDC/ADDE opcodes are currently defined, and to do it you really need to fix the opcode definitions to not involve glue, first. I also note that your transform doesn't actually trigger at all on this particular test case on x86, because the

I'd think i1 would be the proper and correct choice for a carry flag for the generic instruction. I expect that would also make UADDO/USUBO redundant with ADDC/SUBC (which would seem a good outcome). You'd need to make sure the right thing happened when converting from ADDC's 1-bit carry in/out to X86ISD::AD[DC]'s EFLAGS i/o. Right now the conversion can get away with assuming

Would it not make sense to refactor the code so those don't use glue rather than emitting them with glue and then getting rid of it. There are times when we would like to emit these in separate blocks but can't (presumably because of the glue). On Tue, Feb 7, 2017 at 9:15 PM, James Y Knight via llvm-dev < llvm-dev at lists.llvm.org> wrote: > That's seems really odd that

Long story short: https://llvm.org/bugs/show_bug.cgi?id=31890 The backend fails to schedule a given DAG, the reason being that there is an instruction and it glue that needs to be broken apart as they can't be scheduled consecutively. See attached file for a picture of the DAG. Not sure what's the best course of action is, and not sure why this isn't a problem for the X86 backend

Hi, I'm working with workload where the bottleneck is cryptographic signature checks. Or, in compiler terms, most large integer operations. Looking at rL296252 , the state of affair in that area degraded quite significantly, see test/CodeGen/X86/i256-add.ll for instance. Is there some kind of work in progress here and it is expected to get better ? Because if not, that's a big problem.

I'm trying to optimize a pattern that goes roughly as: A / \ B C \ / D Problem is, when A gets modified, B and C get added back to the worklist, but D doesn't. Readding D to the worklist just create an infinite loop where one process D again and again. Is there a proper way to make this work ? -------------- next part -------------- An HTML attachment was scrubbed...

On Wed, 13 Apr 2016 at 09:38 Amaury SECHET <deadalnix at gmail.com> wrote: > I'd be happy to do it, but this is a bit much high level for me to be > actionable. Can you explain me what I should do to reintroduce them int he > debian packaging ? > On the CMake side, I'm not sure. I think it's just a matter of using the "install()" functions to install them

On Sun, 1 May 2016 at 16:12 Amaury SECHET <deadalnix at gmail.com> wrote: > Some update on this. > > 2016-04-12 18:48 GMT-07:00 Andrew Wilkins <axwalk at gmail.com>: > >> On Wed, 13 Apr 2016 at 09:38 Amaury SECHET <deadalnix at gmail.com> wrote: >> >>> I'd be happy to do it, but this is a bit much high level for me to be >>>

A while back, we introduced new attributes to model functions which read and wrote from locations not otherwise visible in the IR. The motivation was to enable much more aggressive aliasing around such calls. Since that time, we've reverted the original patch and AFAIK we have no transformation or analysis passes in tree which use this information. Given this, I don't think it's

On Mon, Feb 22, 2016 at 9:40 PM, Andrew Trick <atrick at apple.com> wrote: > I actually see fences as a proxy for potential inter-process > communication and I/O. It's important that any opaque library call > could contain a fence. This makes perfect sense to me now, especially if you want to use @trap_on for safety checks. Without re-ordering restrictions, a failed @trap_on

Hi, I'm working on a target which have a variable size for CC (the same size as the arguments). As a result getSetCCResultType, return a variable size. In this commit, at the line DAG.getSExtOrTrunc(SetCC, DL, SelectVT), on my target, you end up generating the Node you are replacing, and so creating a loop in the DAG, which give a whole new meaning to the A in the acronym. Subsequent code

Pretty all is in the title. Is there a reason why this isn't done ? With debian and ubuntu switching to PIE by default, this is become more and more of a hassle to get this working properly, and I'd rather see that fixed in LLVM rather than in each driver that do something with it. Has someone already looked into this ? If so, what are the conclusions ? -------------- next part

I may be wrong here, but legalizing early seems like something that is more likely to prevent optimizations than it is to encourage them. But I guess I don't follow why things like TTI, TII and TLI queries don't suffice for this. CodeGenPrepare will break this sequence up. I would imagine that if the target returns false for isCheapToSpeculateCtlz() and false for canInsertSelect(), the

On Wed, 13 Apr 2016 at 08:10 Amaury SECHET via llvm-dev < llvm-dev at lists.llvm.org> wrote: > I'd like to shime in here. These apt repository used to contain packages > named llvm-3.8-tools containing, amongst other things, the lit python > library used to test llvm. It seems that it went away recently and I have > travis build failing because of this. > > What is