search for: splitblock

Hi Fellows, I am writing a pass that requires the DominatorTree pass. In the runOnFunction of my own pass, I call llvm::SplitBlock to split a block (%for.end) at it's first insert point. Then, when I dump my dominator tree immediately after, I can see the newly split %for.end.split, but its DFSNumIn and DFSNumOut are not properly updated in llvm::SplitBlock (i.e., still the initialized -1). At the same time, the DT->dum...

...:59 AM, Andrew Trick <atrick at apple.com> wrote: > > On Feb 13, 2014, at 4:34 PM, Paul Vario <paul.paul.mit at gmail.com> wrote: > > Hi Fellows, > > I am writing a pass that requires the DominatorTree pass. In the > runOnFunction of my own pass, I call llvm::SplitBlock to split a block > (%for.end) at it's first insert point. Then, when I dump my dominator tree > immediately after, I can see the newly split %for.end.split, but its > DFSNumIn and DFSNumOut are not properly updated in llvm::SplitBlock (i.e., > still the initialized -1). At the same...

...des() <CodeExtractor.cpp>. The algorithm first separates the header block into two, one containing only PHI nodes and the other containing the remaining non-PHI nodes. The variable NewBB holds the pointer to the latter half block. Later, it tries to update DT information. if (DT) DT->splitBlock(NewBB); In splitBlock, it checks if the NewBB has only one successor. I'm not sure why this is required, but it will fail on cases where NewBB has multiple successors, which are pretty common. For example, a switch or a conditional branch in NewBB can break this check. Could anyone tell me ho...

...he algorithm first separates the header block into two, one > containing only PHI nodes and the other containing the remaining non- > PHI nodes. The variable NewBB holds the pointer to the latter half > block. Later, it tries to update DT information. > > if (DT) > DT->splitBlock(NewBB); > > In splitBlock, it checks if the NewBB has only one successor. I'm > not sure why this is required, but it will fail on cases where NewBB > has multiple successors, which are pretty common. For example, a > switch or a conditional branch in NewBB can break this c...

In Dominators.h, the splitBlock(NewBB) method assumes that the NewBB has only one successor. I don't see why it cant have more than one successors. Is there a reason? Or it's just assumed that way to simplify things? Thanks a lot. -- Wei Dang -------------- next part -------------- An HTML attachment was scrubbed... UR...

...> The algorithm first separates the header block into two, one containing > only PHI nodes and the other containing the remaining non-PHI nodes. The > variable NewBB holds the pointer to the latter half block. Later, it tries > to update DT information. > > if (DT) > DT->splitBlock(NewBB); > > In splitBlock, it checks if the NewBB has only one successor. I'm not sure > why this is required, but it will fail on cases where NewBB has multiple > successors, which are pretty common. For example, a switch or a conditional > branch in NewBB can break this check....

...try to extract the lone basic block from the following function, I get an assertion error. define i32 @test(i32 %x) { %tmp = call i32 @test3( i32 %x ) ; <i32> [#uses=1] ret i32 %tmp } The assertion error is: lli: Dominators.cpp:71: void llvm::DominatorTree::splitBlock(llvm::BasicBlock*): Assertion `NewBB->getTerminator()->getNumSuccessors() == 1 && "NewBB should have a single successor!"' failed. lli((anonymous namespace)::PrintStackTrace()+0x22)[0x87f7cb8] lli((anonymous namespace)::SignalHandler(int)+0x110)[0x87f7f7c] /lib/tls/libc....

...ly) available everywhere. Is this > covered by your current (or planned) work? I'm not sure what you exactly mean by one shot; I'll ask around tomorrow. I wanted to play a little bit with your work, but run in some issues: > > bin/llvm-as ../test/Analysis/Dominators/2007-07-11-SplitBlock.ll > > bin/dominators -to-graph ../test/Analysis/Dominators/2007-07-11-SplitBlock.bc > | tee graph > p 5 5 1 1 > a 1 3 > a 1 5 > a 2 3 > a 3 2 > a 3 4 > e > > bin/dominators graph > Unknown file format for graph > Invalid input graph > I must do somethin...

...;> >> I have tried to use SplitEdge function, but failed. Actually the third >> parameter is a variable of type Pass and it need to be non-null. But I >> could not figure out how to use it. Please help me out. > > The only reason it needs a non-NULL Pass* is to call llvm::SplitBlock which > uses P->getAnalysisIfAvailable unconditionally. Feel free to wrap those > calls in 'if (P) { ... }' and send us a patch. > > Of course, the obvious question is why aren't you doing your transforms > inside of a Pass? > > Nick > >> Regards, >&g...

Hi, I'm not sure if this is really a problem or not, but I noticed that if you're working with bitcode that has debug metadata, and you split a BasicBlock using llvm::SplitBlock or BasicBlock::splitBasicBlock, the unconditional branch added to the new block will lack debug metadata. This turned out not to be a problem for me, since my analysis pass needs only one instruction in the block to have metadata, but perhaps it will be a problem for others. Ignoring for no...

...gt; instruction like > if Value1 != Value2, error > without create a new block, continuing the execution in the same block, > forcing the LLI to execute this. You can't do that; a br instruction must be at the end of a block. Splitting a block is trivial, though: the C++ API provides SplitBlock, and if you're just manipulating the text, you can insert a br to a label immediately followed by that label anywhere in any function without changing the semantics of the program. -Eli > 2011/9/5 Eli Friedman <eli.friedman at gmail.com> >> >> On Mon, Sep 5, 2011 at 4:47...

...arkar wrote: > Hi, > > I have tried to use SplitEdge function, but failed. Actually the third > parameter is a variable of type Pass and it need to be non-null. But I > could not figure out how to use it. Please help me out. The only reason it needs a non-NULL Pass* is to call llvm::SplitBlock which uses P->getAnalysisIfAvailable unconditionally. Feel free to wrap those calls in 'if (P) { ... }' and send us a patch. Of course, the obvious question is why aren't you doing your transforms inside of a Pass? Nick > Regards, > Chayan > > On Sat, Jul 17, 2010 a...

...// have only one predecessor. > SplitEdge(L->getLoopLatch(), Exit, this); Would it make sense to move the ProfileInfo updating code into SplitEdge? That way all users of SplitEdge would automatically do the right thing. Actually, SplitEdge just delegates to either SplitCriticalEdge or SplitBlock, so those two should do the work. In TailRecursionElimination.cpp, there's logic which uses a "10-fold increase" heuristic. It would be nice if that code were factored out into a utility routine so that the profiling heuristics are more centralized. > - bool Folded = Con...

Hi All, I need to remove successors from every basic block to insert new ones I tried this code, but it doesn't work void RemoveSuccessor(TerminatorInst *TI, unsigned SuccNum) { assert(SuccNum < TI->getNumSuccessors() && "Trying to remove a nonexistant successor!"); // If our old successor block contains any PHI nodes, remove the entry in the //

Hi, I have tried to use SplitEdge function, but failed. Actually the third parameter is a variable of type Pass and it need to be non-null. But I could not figure out how to use it. Please help me out. Regards, Chayan On Sat, Jul 17, 2010 at 10:16 PM, Nick Lewycky <nicholas at mxc.ca> wrote: > Chayan Sarkar wrote: >> >> Hi all, >> >> Suppose in a CFG bb1 has two

Hi all, this (altough a big patch) is actually pretty straight forward: It (tries) to preserve ProfileInfo in all -std-compile-opts passes and all X86-Backend passes. There is still some passes that have corner cases where the ProfileInfo is not correct after the pass. Some passes are still missing... How shall I proceed with this? Andi -------------- next part -------------- A non-text

...have tried to use SplitEdge function, but failed. Actually the third >>> parameter is a variable of type Pass and it need to be non-null. But I >>> could not figure out how to use it. Please help me out. >> >> The only reason it needs a non-NULL Pass* is to call llvm::SplitBlock which >> uses P->getAnalysisIfAvailable unconditionally. Feel free to wrap those >> calls in 'if (P) { ... }' and send us a patch. >> >> Of course, the obvious question is why aren't you doing your transforms >> inside of a Pass? >> >> Nick &...

Hi all, I'm a beginner in LLVM. Currently, I want to implement a pass that generates a jump table. The entry in that table is a jump to some place (may be an instruction) in a basic block. I'm reading the JumpTable code in llvm 3.5, there is a table which contains jump entries to functions. In AsmPrinter::doFinalization function from file lib/CodeGen/AsmPrinter/AsmPrinter.cpp, it gets a

Hi, I want to copy some dependent statements, like a = b, b = c, from one basicblock to another basicblocks. Because of SSA, a = b, will be like %1 = load %b, store %1, %a. If I just use clone() method in Instruction class, it will be like <badref> = load %b, store <badref>, %a. If I need remap the virtual registers, this map just will affect the whole module? And how to use it? I am

I have two values and I want see if them are equals. Then, I would a instruction like if Value1 != Value2, error without create a new block, continuing the execution in the same block, forcing the LLI to execute this. 2011/9/5 Eli Friedman <eli.friedman at gmail.com> > On Mon, Sep 5, 2011 at 4:47 PM, Rafael Baldiati Parizi > <parizi.computacao at gmail.com> wrote: > >