similar to: [LLVMdev] hazard scheduling nodes

On Feb 21, 2013, at 9:11 AM, Jonas Paulsson <jonas.paulsson at ericsson.com> wrote: > Hi, > > I am trying to add Hazard scheduling nodes after buildSchedGraph(), with a scheduler derived from ScheduleDAGInstrs. I get weird errors, so I wonder what I am doing wrong? > > What I am doing right now is: > > I have a created MI with opcode HAZARD that does not have

Hi Andy, The thing is that I was trying to build a sched graph in other places than these two standard scheduling passes. For instance, in pre-emit. I would like to reschedule a basic block on my vliw target just before assembly emission. I tried to add SUnits for hazards in an experiment, but this gave very weird errors... even while allocating extra space in SUnits vector. For some function, I

Hi, Can anyone help me to understand the ScheduleDAGInstrs::buildSchedGraph() method? I find the handling of AliasChain is disturbing since: 1. A new alias chain add deps to all possibly aliasing SUs, and then clears those lists. 2. When AliasChain is present, the addChainDependency() method is called, but the target hook areMemAccessesTriviallyDisjoint() called inside

Hello again, Sorry -- I think I found the problem somewhere else. I was a bit confused and missed the fact that adjustChainDeps() is called a few lines down and does just what I wanted :-) I would like to instead ask another question: Why is I->isCtrl() used in code like // Iterate over chain dependencies only. for (SUnit::const_succ_iterator I = SUb->Succs.begin(), E =

Hi, Thank you for the reply. >It looks to me like we can choose any subset of edges here and be correct. We're basically trying to prune/pinch the DAG edges here. They can easily blow up with AA sched. I would guess that isCtrl() edges are good ones to bypass because they could be a low-latecy edges, whereas true data dependencies from a load are expected to be >higher latency, so they

Hi Hal, Thanks. How about a symbol with two different immediate offsets - the Value* would be the same, right? I don't see how AliasAnalysis::Location would handle this... And BasicAliasAnalysis does if (V1 == V2) return MustAlias; , so I'm not sure how this would be done .. ? /Jonas > -----Original Message----- > From: Hal Finkel [mailto:hfinkel at anl.gov] > Sent:

On Apr 17, 2013, at 2:33 AM, Hal Finkel <hfinkel at anl.gov> wrote: > ----- Original Message ----- >> From: "Jonas Paulsson" <jonas.paulsson at ericsson.com> >> To: "Hal Finkel" <hfinkel at anl.gov> >> Cc: llvmdev at cs.uiuc.edu >> Sent: Wednesday, April 17, 2013 12:22:49 AM >> Subject: RE: [LLVMdev] alias analysis in backend

----- Original Message ----- > From: "Jonas Paulsson" <jonas.paulsson at ericsson.com> > To: "Hal Finkel" <hfinkel at anl.gov> > Cc: llvmdev at cs.uiuc.edu > Sent: Wednesday, April 17, 2013 12:22:49 AM > Subject: RE: [LLVMdev] alias analysis in backend > > Hi Hal, > > Thanks. How about a symbol with two different immediate offsets - the

----- Original Message ----- > From: "Andrew Trick" <atrick at apple.com> > To: "Hal Finkel" <hfinkel at anl.gov> > Cc: "Jonas Paulsson" <jonas.paulsson at ericsson.com>, llvmdev at cs.uiuc.edu > Sent: Thursday, April 18, 2013 2:33:52 AM > Subject: Re: [LLVMdev] alias analysis in backend > > > On Apr 17, 2013, at 2:33 AM,

On Jan 17, 2014, at 4:03 PM, Andrew Trick <atrick at apple.com> wrote: > > On Jan 17, 2014, at 3:54 PM, Hal Finkel <hfinkel at anl.gov> wrote: > >> Andy, et al., >> >> In ScheduleDAGInstrs::buildSchedGraph, the code for handling stores has this: >> >> if (!ExitSU.isPred(SU)) >> // Push store's up a bit to avoid them

On Thu, Mar 29, 2012 at 02:57:27PM -0500, Sergei Larin wrote: > Tom, > > I do not have your call stack, but packetizer calls > ScheduleDAGInstrs::buildSchedGraph to create dependency model. If this is > the first time you use the new MI sched infrastructure (like your target has > not implemented misched yet) there might be some work needed to implement > couple target

I think those should be considered internal options for (llvm codegen) developers, a normal compiler user should not need to use any of them. Of course you can look around the llvm sourcecode (esp. in lib/CodeGen/MachineScheduler.cpp) and see what cl::opt options are available and how they affect the scheduler operation. In case of the MachineScheduler all settings are the same regardless of the

I see that there are several options to influence instruction scheduling, but there doesn't seem to be a lot of information about what they do, for example: -misched-topdown -misched-bottomup The description in MachineScheduler.cpp says: "Force top-down list scheduling" and "Force bottom-up list scheduling" Which isn't too helpful - where might I want to use these?

Andy, et al., In ScheduleDAGInstrs::buildSchedGraph, the code for handling stores has this: if (!ExitSU.isPred(SU)) // Push store's up a bit to avoid them getting in between cmp // and branches. ExitSU.addPred(SDep(SU, SDep::Artificial)); This code does not seem to be in any way specific to compares; and in any case, at least on the PPC A2, scheduling stores in

On Mar 29, 2012, at 1:18 PM, Tom Stellard <thomas.stellard at amd.com> wrote: > On Thu, Mar 29, 2012 at 02:57:27PM -0500, Sergei Larin wrote: >> Tom, >> >> I do not have your call stack, but packetizer calls >> ScheduleDAGInstrs::buildSchedGraph to create dependency model. If this is >> the first time you use the new MI sched infrastructure (like your

Hi, I would be happy to give it a try :-) The fact that AA was added at a later point explains the situation a bit, as much fewer SUs should end up in RejectMemNodes without it. RejectMemNodes is bad in that it mixes all the SUs together again, after having gone through the work of separating them by analyzing their underlying objects. It is also very confusing to have two "stages" of

On Wed, Sep 25, 2013 at 1:15 PM, Andrew Trick <atrick at apple.com> wrote: > > On Sep 24, 2013, at 7:59 PM, Liu Xin <navy.xliu at gmail.com> wrote: > > Hi, Andrew, > > Thank you for answering my question. > > What's the status of misched? is it experimental? I found it is disabled > by default for all architectures(3.4svn). I also don't understand

Hi, Andrew, Thank you for answering my question. What's the status of misched? is it experimental? I found it is disabled by default for all architectures(3.4svn). I also don't understand the algorithm. Could you point to me more papers or text materials about your approach? it seems that you want to balance register pressure and ILP in misched. On Tue, Sep 24, 2013 at 4:07 PM,

On Sep 25, 2013, at 11:03 PM, Liu Xin <navy.xliu at gmail.com> wrote: > > > > On Wed, Sep 25, 2013 at 1:15 PM, Andrew Trick <atrick at apple.com> wrote: > > On Sep 24, 2013, at 7:59 PM, Liu Xin <navy.xliu at gmail.com> wrote: > >> Hi, Andrew, >> >> Thank you for answering my question. >> >> What's the status of

Hi, I have revisited the issue in buildSchedGraph() I talked about previously, and attached a few patches. The first tries to fix the issue, and the other two try to illustrate associated issues, emerged from applying it. Is it OK to commit the first patch? [PATCH] Bugfix for missed dependency from store to load in buildSchedGraph(). Bugfix for missed dependency from store to load in