similar to: [LLVMdev] post-dominance frontier

On Thu, 9 Nov 2006, Ryan M. Lefever wrote: Sorry I never responded to this: > In the literature (see below for a reference), when a dominance frontier > is computed, it is computed from a CFG that contains a dummy entry node > and dummy exit node. Further, those dummy nodes are potential members > of the (post-)dominance frontier for a given basic block. In LLVM, I > could not

I think you can refer to lib/VMCore/AsmWriter.cpp for these things. E.g., You can use 'if(I.isTerminator())' if a instruction 'I' is terminator. You can use 'if (isa<BranchInst>(I))' if a instruction 'I' is 'br' instruction. and so on... Thx, Seung Jae Lee ---- Original message ---- >Date: Mon, 2 Jul 2007 17:15:00 -0400 (EDT) >From: abhi232

> On Mon, 2 Jul 2007 abhi232 at cc.gatech.edu wrote: >> Hello all, >> I am new to the llvm infrastructure so if this question is already >> resolved please redirect me to that link. >> >> I am writing a pass for flow sensitive and context sensitive alias >> analysis.for that i require the previous and next instruction of all the >> instructions.Is there

Hi Henrique, Thanks for the quick reply! On Tue, Nov 12, 2013 at 9:13 PM, Henrique Santos < henrique.nazare.santos at gmail.com> wrote: > PRE normally uses a latest placement algorithm to do something of the sort. > I don't know about GVN/PRE, but older version of PRE might have it. > Just placing the calls to free at the predecessors (dominated by BB12) of > the dominance

> > It seems that placing the calls to free at the predecessors of dominance > frontier is inadequate. It is possible that there are exit blocks that are > dominated by BB12 (calls to malloc). I guess we can also insert calls to > free at these exit blocks too. That crossed my mind a few minutes later. : ) If you're interested, PRE.cpp existed last at r25315. It calculates the

Hi all, I have been writing a pass to heapify some alloca's (it is pessimistization, not optimization). For example, in the following control flow graph, there is a call to malloc inserted in block BB12. In order to avoid memory leak, free's are needed. The free cannot be inserted in BB23 because BB23 is not dominated by BB12. There are two ways to go I can think of here. One way is to

Thanks! I will try that and see whether it works. On Wed, Nov 13, 2013 at 5:01 AM, Henrique Santos < henrique.nazare.santos at gmail.com> wrote: > It seems that placing the calls to free at the predecessors of dominance >> frontier is inadequate. It is possible that there are exit blocks that are >> dominated by BB12 (calls to malloc). I guess we can also insert calls to

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 ... / \ / \

I'm attempting to modify a parser generator to emit LLVM code instead of C. So far the experience has been trivial, but I am now running into an error regarding labels that I can't seem to solve. Situation 1: A label is used immediately after a void function call (l6 in this case): <snip> %tmp26 = load i32* @yybegin, align 4 %tmp27 = load i32* @yyend, align 4 call void

On Mon, 2 Jul 2007 abhi232 at cc.gatech.edu wrote: > Hello all, > I am new to the llvm infrastructure so if this question is already > resolved please redirect me to that link. > > I am writing a pass for flow sensitive and context sensitive alias > analysis.for that i require the previous and next instruction of all the > instructions.Is there an intrinsic that can help me

Thanks a lot for the help guys.. I will try to get the information on these lines... Thank you once again... Will bug you guys after some time now. :) > I think you can refer to lib/VMCore/AsmWriter.cpp for these things. > > E.g., > You can use 'if(I.isTerminator())' if a instruction 'I' is terminator. > You can use 'if (isa<BranchInst>(I))' if a

PRE normally uses a latest placement algorithm to do something of the sort. I don't know about GVN/PRE, but older version of PRE might have it. Just placing the calls to free at the predecessors (dominated by BB12) of the dominance frontier of BB12 seems to work, however. Is there anything wrong with this? H. On Tue, Nov 12, 2013 at 11:30 PM, Bin Tzeng <bintzeng at gmail.com> wrote:

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).

Hello all, I am new to the llvm infrastructure so if this question is already resolved please redirect me to that link. I am writing a pass for flow sensitive and context sensitive alias analysis.for that i require the previous and next instruction of all the instructions.Is there an intrinsic that can help me getting the instruction numbers directly because i read at the llvm.org website making

Bill, Just in case this is relevant for you: If you're working with C++ code, or otherwise have any functions that might throw exceptions, you might also need to catch those exceptions in order to free the allocated memory. This will involve looking for calls to functions that mayThrow(), changing their calls to invokes, and freeing the memory before resuming the unwinding. -Hal -----

Hi, I found that LLVM 3.1 says Dominance frontier is deprecated. Can anyone please tell me, if there is any replacement for Dominance frontier & Postdominance frontier in LLVM? What are the options if we need to use them? Thanks, Swarup. -------------- next part -------------- An HTML attachment was scrubbed... URL:

I just finished upgrading our LLVM to 2.4 and I immediately ran into a problem with dominance frontier calculation: llvm/lib/VMCore/PassManager.cpp:714: void llvm::PMDataManager::verifyDomInfo(llvm::Pass&, llvm::Function&): Assertion `0 && "Invalid dominator info"' failed. Strangely enough, the Pass running when the assert triggers is Dominance Frontier

On Feb 18, 2009, at 8:00 AM, David Greene wrote: > I just finished upgrading our LLVM to 2.4 and I immediately ran into > a problem > with dominance frontier calculation: > > llvm/lib/VMCore/PassManager.cpp:714: void > llvm::PMDataManager::verifyDomInfo(llvm::Pass&, llvm::Function&): > Assertion > `0 && "Invalid dominator info"' failed.

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. >>>

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