similar to: LLVM Pass To Remove Dead Code In A Basic Block

> On 25 May 2018, at 01:46, Aaron via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > Hi all, > > LLVM optimization pass gives an error "Terminator found in the middle of a basic block!" since basic block IR may have multiple "ret" instructions. It seems LLVM does not accept multiple return in a basic block by default. > Yes, if you’re inserting

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

On Feb 1, 2011, at 1:34 PM, Andrew Trick wrote: > On Feb 1, 2011, at 1:08 PM, Andrew Clinton wrote: > >> I have a (non-entry) basic block that contains only PHI nodes and an >> unconditional branch (that does not branch to itself). Is it always >> possible to merge this block with it's successor and produce a >> semantically equivalent program? I'm

Here's what I've got so far - it seems to work, aside from the fact that DeleteDeadPHIs is not removing at least one dead PHI in my test program. --------------------- static bool mergeBlockIntoSuccessor(BasicBlock *pred, BasicBlock *succ) { if (succ == pred) return false; if (pred->getFirstNonPHI() != pred->getTerminator()) return false; //

Recently wrote a pass that inserts a preheader for a loop that doesn't have one. When I tried to run it, I ran into a problem that became obvious in hindsight - the PHINodes need to be updated in places where the incoming control-edge has changed. Is there anything else that can be affected when a block is inserted into the CFG? Also, planning to write a helper function which will take care

Hello all, I was playing with LLVM pass. I changed the lib/Transforms/Hello/Hello.cpp 's content to be my own pass. Then I make install the pass and use an example test1.c to see whether it works or not. When I run example using the following command: clang -emit-llvm test1.c -c -o test1.bc opt -load ../build_llvm/Debug+Asserts/lib/LLVMHello.so -hello < test1.bc > /dev/null It

I have the following C source: extern unsigned int donut; void f1(); void f2(); void f1() { unsigned int *magic = &donut; if (*magic != 286529877) { f2(); } } void f2() { /* Loop here forever if application is built with wrong version of ROM image */ while(1) { ; } } The -O2 level PruneEH pass uses SimplifyFunction() which contains this code: for

Hi I have checked all blocks, each block have a Terminator instruction and each blocks belongs to a function. I'm really confused. I guess the problem is caused by the removal of the Loop,The code is as follows: * //every block to header (except the ones in the loop), will now redirect to newblock for (pred_iterator PI = pred_begin(header); PI != pred_end(header); ++PI) {

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

Hi, All I want to implement DSWP Which is used for parallelization of loops. For this purpose, the loop was replaced with a new basic block in main function. And new functions were created and basic blocks of Loop assigned to them.I have checked blocks and branches for Succ and Pred relation and I have not found any problems. However I get the following error: * **opt:

Here is the code snippet that I am using to create the PHIs in the loop according to the PHIs in the new preheader. At this point I have already redirected the loop backedge and removed the preheader from the loop. for (BasicBlock::iterator II = loopHeaderBB->begin(); (PN=dyn_cast<PHINode>(II)); ++II) { // remove loop back PHI and add it to split BB

The clone llvm:CloneBasicBlock copies the phi function in the replicated basic block from the original basic block. I don't want the copy of phi in relplicated block. For now I am creating .bc file with -O0 option so that it doesn't generate phi function in first place. Is this a good approach or there are some other function available for it. Tarun On Sun, Apr 17, 2011 at 5:22 AM, Eli

Hi LLVMers, the example attached I have used to prove that JIT and some visible optimizations are really invoked. Proved OK. I got 30% speed-up in comparison to gcc 3.3.3 on my Athlon XP 1500. Nice. P.S. guys, no fears, I don't plan to flood the cvs repository with my "brilliant" examples ;) --- Valery A.Khamenya -------------- next part -------------- An

On Tue, 17 Aug 2004, Reid Spencer wrote: > That's pretty cute actually. Do you want this "brilliant" :) example in the cvs > repository? I'd be happy to put it in. Here's an idea: how about we take the ModuleMaker, Valery's previous example, and this one and put them all in one "small examples" project? -Chris > Valery A.Khamenya wrote: > >

On Thu, 17 Feb 2005, Tanu Sharma wrote: > I created a new block and inserted it into the present basic block list > , but I get this error: > > opt: BasicBlock.cpp:83: virtual llvm::BasicBlock::~BasicBlock(): Assertion `getParent() == 0 && "BasicBlock still linked into the program!"' failed. > > The program completes its task and i get this in the end. I am

hacker cling wrote: > Hello all, > I was playing with LLVM pass. I changed the > lib/Transforms/Hello/Hello.cpp 's content to be my own pass. Then I make > install the pass and use an example test1.c to see whether it works or > not. When I run example using the following command: > clang -emit-llvm test1.c -c -o test1.bc > opt -load

Valery, That's pretty cute actually. Do you want this "brilliant" :) example in the cvs repository? I'd be happy to put it in. Reid. Valery A.Khamenya wrote: > Hi LLVMers, > > the example attached I have used to prove that JIT and some visible > optimizations are really invoked. > > Proved OK. I got 30% speed-up in comparison to gcc 3.3.3 >

I guess I thought that once I redirected the branches and created new PHIs that LLVM would correct the variable usage when I return true (changed CFG) from the pass. Is this not the case? On Wed, Mar 7, 2012 at 4:08 PM, Ryan Taylor <ryta1203 at gmail.com> wrote: > Here is the code snippet that I am using to create the PHIs in the loop > according to the PHIs in the new preheader. At

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

> Compiling InstrSelectorEmitter.cpp > InstrSelectorEmitter.cpp: In member function `virtual void > llvm::InstrSelectorEmitter::run(std::ostream&)': > InstrSelectorEmitter.cpp:1295: internal compiler error: in > convert_from_eh_region_ranges_1, at except.c:1159 > Please submit a full bug report, GCC 3.3.2 is not compatible with LLVM, sorry! -Chris > with