similar to: [LLVMdev] Splitting a basic block creates an instruction without debug metadata

On Oct 27, 2010, at 5:53 PM, Trevor Harmon wrote: > 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

Hi, I'm writing a pass that does some static analysis on C code. A critical requirement of the pass is that it must preserve not only the correctness of the code but also its timing -- It cannot add or remove even one CPU cycle from the resulting machine code. To put it another way, the binary executable that is produced when the pass is present must be identical to what is produced

On Oct 20, 2010, at 5:16 PM, Trevor Harmon wrote: > I'm writing a pass that does some static analysis on C code. A > critical requirement of the pass is that it must preserve not only the > correctness of the code but also its timing -- It cannot add or remove > even one CPU cycle from the resulting machine code. To put it another > way, the binary executable that is

On Wed, Oct 20, 2010 at 7:19 PM, Jim Grosbach <grosbach at apple.com> wrote: > > On Oct 20, 2010, at 5:16 PM, Trevor Harmon wrote: >> I'm writing a pass that does some static analysis on C code. A >> critical requirement of the pass is that it must preserve not only the >> correctness of the code but also its timing -- It cannot add or remove >> even one CPU

Hi Devang, Thanks for your reply. But if you look at the comment of BasicBlock::splitBasicBlock(), it says that "...an unconditional branch is added to the new BB, and the rest of the instructions in the BB are moved to the newBB, including the old terminator." So, the terminator of the newBB is exactly the same as the terminator of the oldBB. IF the oldBB has multiple successors,

On Nov 19, 2008, at 7:41 AM, Jack Tzu-Han Hung wrote: > Hi, > > I found a problem in CodeExtractor::severSplitPHINodes() > <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.

Hi, I found a problem in CodeExtractor::severSplitPHINodes() <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

Hi, I want to insert a conditional branch in the middle of a basic block. To that end, I am doing these steps: (1) Split the basic block: bb->splitBasicBlock() (2) Remove the old terminator: succ->removePredecessor(bb) bb->getTerminator()->getParent() (3) Adding a new terminator: BranchInst::Create(ifTrue, ifFalse, cnd, "", bb); That seems to work, but later passes

On May 8, 2009, at 4:02 PM, Nick Johnson wrote: > I want to insert a conditional branch in the middle of a basic block. > To that end, I am doing these steps: > > (1) Split the basic block: > bb->splitBasicBlock() > > (2) Remove the old terminator: > succ->removePredecessor(bb) > bb->getTerminator()->getParent() Assuming that the new block will still be a

On Oct 20, 2010, at 5:26 PM, Kenneth Uildriks wrote: > You could always undo the split right before your pass finishes. How would I undo a split? Perhaps by merging them back using llvm::MergeBlockIntoPredecessor? Trevor

Hi, I have been trying to move some instructions between basic blocks , After looking at the API , I found llvm::Instruction::clone() but there is no result value for this. For example- source Basic block : continuation: ; preds = %else, %then %iftmp = phi i32 [ 5, %then ], [ 9, %else ] store i32 %iftmp, i32* %datasize ; 3 instructions below

Hi Dean, Thanks for your reply. That's exactly what I am doing, but I was looking for a default optimization or pass implementation if there was. I used BasicBlock::splitBasicBlock() but it puts "br" end of original basic block. I tried to delete the br instruction by using eraseFromParent() but it didn't work. I had to rewrite my own splitBasicBlock() by modifying the

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

Hello, I would like to see if this issue is a result of a misunderstanding on my part before I file a bug. I am using LLVM 3.4, built from the source tarballs. My system's uname is "Darwin tyler-air 12.5.0 Darwin Kernel Version 12.5.0: Sun Sep 29 13:33:47 PDT 2013; root:xnu-2050.48.12~1/RELEASE_X86_64 x86_64". All I'm trying to do is add a runtime check after all call

> On 25 May 2018, at 03:53, Aaron <acraft at gmail.com> wrote: > > Hi Dean, > > Thanks for your reply. > > That's exactly what I am doing, but I was looking for a default optimization or pass implementation if there was. > There’s a dead code elimination pass, but it works with a control flow graph (it removes basic blocks that are unreachable after constant

Hi All, Still I could not figure out how to use Pass* while calling SplitEdge() function. Can anyone provide me some example? Regards, Chayan On Sun, Jul 18, 2010 at 11:49 PM, Nick Lewycky <nicholas at mxc.ca> wrote: > Chayan Sarkar wrote: >> >> Hi, >> >> I have tried to use SplitEdge function, but failed. Actually the third >> parameter is a variable of

Hi, I could not figure out, how to declare a Pass*. Can anyone give me an example, how to use SplitEdge() function ? Please help me out. Regards, Chayan On Tue, Jul 20, 2010 at 10:12 AM, Chayan Sarkar <chayan.ju at gmail.com> wrote: > Hi All, > > Still I could not figure out how to use Pass* while calling > SplitEdge() function. Can anyone provide me some example? > >

Chayan Sarkar 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

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

Hi, Yeah I found that it is running LLVM's functions. The functions that are running are: main llvm.dbg.func.start llvm.dbg.stoppoint scanf llvm.dbg.region.end But I dont want all the functions to be called as I am using Dominator Trees and whenever I the statement DominatorTree &DT = getAnalysis<DominatorTree>(F); is encountered by functions other than main, it gives error.