similar to: Collectively dominance

Hi Daniel, I mean "*As a set*, B + C dominate D". On Tue, Apr 25, 2017 at 5:42 PM, Daniel Berlin <dberlin at dberlin.org> wrote: > When you say collectively, you mean "would dominate it if considered a > single block together? > > IE > > A > / \ > B C > \ / > D > > As a set, B + C dominate D. > > The set you are

On Tue, Apr 25, 2017 at 6:32 PM, Daniel Berlin <dberlin at dberlin.org> wrote: > > > On Tue, Apr 25, 2017 at 6:17 PM, Hongbin Zheng <etherzhhb at gmail.com> > wrote: > >> Hi Daniel, >> >> I mean "*As a set*, B + C dominate D". >> >> On Tue, Apr 25, 2017 at 5:42 PM, Daniel Berlin <dberlin at dberlin.org> >> wrote:

Hi Daniel, Thanks a lot for all these explanation, I will try it out. Hongbin On Tue, Apr 25, 2017 at 7:04 PM, Daniel Berlin <dberlin at dberlin.org> wrote: > > > On Tue, Apr 25, 2017 at 6:42 PM, Hongbin Zheng <etherzhhb at gmail.com> > wrote: > >> >> >> On Tue, Apr 25, 2017 at 6:32 PM, Daniel Berlin <dberlin at dberlin.org> >> wrote:

Like I said, i'm nearly positive there is a much faster way, as the sets are mostly shared except in the cyclic case, and in all reducible cyclic cases, removal of back-arcs does not affect dominance (because in any reducible flowgraph, v dominates u whenever u,v is a back-arc) On Tue, Apr 25, 2017 at 7:38 PM, Hongbin Zheng <etherzhhb at gmail.com> wrote: > Hi Daniel, > >

On Sat, Jan 7, 2012 at 12:14 AM, Cameron Zwarich <zwarich at apple.com> wrote: > On Jan 6, 2012, at 8:27 PM, Daniel Berlin wrote: > > Note: GCC takes exactly the same approach as LLVM here, for exactly > the reason chris specifies. > In fact, until we started local SSA updating (which is now many years > ago, but ...), dominance frontier calculation for ssa updating was in

On Fri, Jul 15, 2016 at 2:44 PM, Sanjoy Das <sanjoy at playingwithpointers.com> wrote: > Hi Daniel, > > Daniel Berlin wrote: > > Don't we have the same problems for "exit(0)" > > > > > > This is a noreturn call, so yes, iit has another hidden control > > flow-side-effect of a slightly different kind. GCC models it as an extra >

On Jan 6, 2012, at 8:27 PM, Daniel Berlin wrote: > Note: GCC takes exactly the same approach as LLVM here, for exactly > the reason chris specifies. > In fact, until we started local SSA updating (which is now many years > ago, but ...), dominance frontier calculation for ssa updating was in > the top 10 profile functions for GCC compiles of large source files. > I had tried a

On Fri, Jan 6, 2012 at 8:17 PM, Chris Lattner <clattner at apple.com> wrote: > > On Jan 6, 2012, at 5:08 PM, Chris Lattner wrote: > >>>> >>>> It's very like SSA construction, but must make provision >>>> testing anti dependences.  I had planned to use dominance frontiers to >>>> guide placement of phi nodes, as usual. >>>

Hi Daniel, Daniel Berlin wrote: > /* Add fake edges to the function exit for any non constant and non > noreturn calls (or noreturn calls with EH/abnormal edges), > volatile inline assembly in the bitmap of blocks specified by > BLOCKS > or to the whole CFG if BLOCKS is zero. > ... > > The goal is to expose cases in

Hi folks, For the past month I’ve been working on improving the DominatorTree and PostDominatorTree in LLVM. The RFC that explains the motivations and plans can be found here: http://lists.llvm.org/pipermail/llvm-dev/2017-June/114045.html . Here’s a short summary of what changed upstream since posting it: - We switched from the Simple Lengauer-Tarjan algorithm for computing dominators

Hi, Is there a pass in LLVM that can optimize: if (x) a[i] = y0; else a[i] = y1; to a[i] = x ? y0 : y1? I tried opt (3.9) with -O3 but looks like such an optimization do not happened. Thanks Hongbin -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20170425/6ddb8d7e/attachment.html>

Hi Andrew, Thanks a lot. But the function "DT->dominate(A,B)" decides the dominance relationship through comparing the DFS numbers, right? At least, in my example, when I check whether the newly split node (i.e., % *for.end.split*) DOMINATES the original node (I.e., %for.end), the answer is true, which is obviously wrong. Paul On Fri, Feb 14, 2014 at 1:59 AM, Andrew Trick

When looking into https://llvm.org/bugs/show_bug.cgi?id=24866, I discovered that the root cause of the crash is that I was expecting every basic block to have a corresponding Node in the dominator tree. Apparently, the "while.end" basic block in the example does not have a Node in the Dominator Tree. Can anyone tell me if this is expected? If so, under what circumstances?

Hi, guys, what is the interface for finding the immediate dominator of a machine basic block in LLVM 2.1? I found some methods to check if a node dominates other in llvm::MachineDominatorTree, but I was looking for something like: MachineBasicBlock * mbb = ... MachineBasicBlock * iDom = XXX->getImmediateDominator(mbb); is there something similar? best, Fernando

There is PostDominatorTree for determining post-dominance. Even if A post-dominates B and B is executed, that doesn't guarantee that A will be executed. For example, there could be an infinite loop in-between. Strong post-dominance makes the stronger guarantee that there will be no infinite loop from B to A. Do we have anything in LLVM for determining strong post-dominance and in general for

Thanks, Looks like inst combine do the job On Tue, Apr 25, 2017 at 9:36 PM, Davide Italiano <davide at freebsd.org> wrote: > On Tue, Apr 25, 2017 at 9:24 PM, Hongbin Zheng via llvm-dev > <llvm-dev at lists.llvm.org> wrote: > > Hi, > > > > Is there a pass in LLVM that can optimize: > > > > if (x) > > a[i] = y0; > > else > >

Hi Henrique, I have tried using -mergereturn and inserting a free into the predecessors of dominance frontier of malloc block and it caused double free. It is possible for multiple free's to be inserted on the path from malloc to an exit. For example, in the following CFG: BB10 (malloc) / \ BB11 BB12 ... / \ / \

In your original file, %6 is defined in if.end11 and is used in cond.end. if.end11 branches to cond.true and cond.false, both of which branch unconditionally to cond.end. Therefore %6 dominates its use. In your second file %18 is defined in end.11 and used in cond.end. However, end.11 no longer dominates cond.end because you have rewritten all branches to go through the switch statement in

Try breaking the critical edges (-break-crit-edges). This way, a new block will be created between BB13 and BB11 (call this BB11.break) and BB15 and BB12 (call this BB12.break). The predecessors of the dominance frontier will, thus, be BB11.break, BB12.break, and BB14. When we enter through a block with a call to malloc(), we will end up in one of the blocks in the dominance frontier (kind of).

Hi! I'm having some trouble with a pass I'm writing. I'm using DemotePHIToStack to remove all phi node in my code with this code (this is the first thing I do in my pass): // Erase phi node vector<PHINode*> phis; for (Function::iterator i=f->begin();i!=f->end();++i) { for(BasicBlock::iterator b=i->begin();b!=i->end();++b) {