similar to: [LLVMdev] Problems with eraseFromParent()

Alysson wrote: > Hi LLVMers, > > I am working on my llvm school project optimization pass. It's > relatively simple, and it tries to remove redundant bitcast instructions > followed by load instructions. At first, I'm using as input a bytecode > generated by a simple Java test program. > I've already found the reduntant instructions by looking at it's

Hello David, I am having an issue with some custom intrinsics that return a token value: InstCombine deletes the users of the token but not the instruction that creates the token itself. The IR is still valid but it's wasted. The source of the issue is coming from an old patch of yours: commit 7204cff0a121ebc770cf81f7f94679ae7324daae Author: David Majnemer <david.majnemer at

Yes, it's still respected in this case, as the only instructions that will be deleted have been RAUW with undef. Originally, all instructions where RAUW but only non-EHPad were deleted (that means EHPad were RAUW but not deleted). Then it was later patched by not RAUW token instructions and now not deleting EHPad nor token instructions. My assumption is that the instructions we wanted to

Hi, I have two functions in a module, X.foo, which is the callee, and Y.foo2, which calls X.foo. If i either try to run llvm::Function::eraseFromParent() on any one of the functions, i'll get this assertion error: F is used in instruction: %"calling function" = call i32 @X.foo(i32 %read) F is used in instruction: %"calling function" = call i32 @X.foo(i32 %read) While

I did not observe any assertion. In addition, the documentation ( https://llvm.org/docs/LangRef.html#undefined-values) says: The string ‘undef’ can be used anywhere a constant is expected, and indicates that the user of the value may receive an unspecified bit-pattern. Undefined values may be of any type (other than ‘label’ or ‘ void’) and be used anywhere a constant is permitted. Either way,

Hi, LLVMers, I am a CS student in my final year, and I would like to use LLVM in my final course project. So, I just download LLVM and VMKit, and I have been playing with both. I can produce llvm bytecodes from java programs, and now my idea is to remove redundant type checks from the code. For instance, if we consider a program like this: if (o instanceof A) { A a = (A) o; // do

I'm now writing a pass and I wanna ask a question about how to duplicate the function and add duplicated arguments in llvm, for example: func(int a, char *b) -> func(int a, char *b, int a1, char *b1) I'm now stuck at using "getOrInsertFunction" and how to handle "getArgumentList", please share your opinion, thanks a lot! James

Hi, I have: ... @.str1 = private unnamed_addr constant [21 x i8] c"Now f is a function\0A\00", align 1 ; Function Attrs: ssp uwtable define i32 @_Z1fv() #2 { entry: %call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([21 x i8]* @.str1, i32 0, i32 0)) ret i32 0 } Then I get after trying to erase the function from the module: 511

For LLDB I'm writing a dumb module pass that removes all global variables, by running the following code: bool erased = true; while (erased) { erased = false; for (Module::global_iterator gi = llvm_module.global_begin(), ge = llvm_module.global_end(); gi != ge; ++gi) { GlobalVariable *global_var =

I would delete the Loop. I used the following code. cout << "begin to delete loop" << endl; for (Loop::block_iterator bi = L->block_begin(), bi2; bi != L->block_end(); bi = bi2) { bi2 = bi; bi2++; BasicBlock * BB = *bi; for (BasicBlock::iterator ii = BB->begin(), ii2; ii != BB->end(); ii= ii2) { ii2 = ii;

Hi. This is part of my code: ... if (auto* op = dyn_cast<BinaryOperator>(&I)) { Value* lhs = op->getOperand(0); Value* rhs = op->getOperand(1); Value* mul = builder.CreateMul(lhs, rhs); for (auto& U : op->uses()) { User* user = U.getUser(); user->setOperand(U.getOperandNo(), mul); } I.eraseFromParent(); } ... This leads to the following

I found that LLVM optimized the IR by replacing printf with puts. I wondered which pass did this optimization? And is it common that puts is faster (and some other metric) than printf? -- Thanks Thomson -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20120617/08aa6c45/attachment.html>

The code is really simple. But I can not the reason for the segmentation fault. I only know that the eraseFromParent() function leads to it. The whole code is: ... bool runOnFunction(Function &F) override { for (auto &I : instructions(F)) { if (auto* op = dyn_cast<BinaryOperator>(&I)) { IRBuilder<> builder(op); Value* lhs = op->getOperand(0); Value* rhs =

Thanks Bjorn! But The problem is still there. On Wed, Aug 8, 2018 at 2:04 AM, Björn Pettersson A < bjorn.a.pettersson at ericsson.com> wrote: > It looks quite dangerous to erase the instruction I inside the loop when > iterating over all instructions in the function. > I guess it depends on how the range based iterator is implemented if that > works or not. > > I think

I am confused by GlobalVariable::eraseFromParent's declaration: /// This method unlinks 'this' from the containing module and deletes it. void eraseFromParent(); In Globals.cpp the unlinking is done and SymbolTableListTraits cleans up the symbol table but I don't see anything that actually deletes the object. Is the comment misleading or am I missing something?

hi i want replacing a global variable by a constant value for erase instruction. i had seen the code that as follows for (llvm::GlobalVariable::use_iterator U = gv->use_begin(); U != gv->use_end();--U ) { llvm::Instruction *I = llvm::cast<llvm::Instruction>(U); I->replaceAllUsesWith(constPtr); I->eraseFromParent(); } but i dont know how can declare constptr.

Hi. Thanks. I changed the code but the problem exists. This is my new code which is again very simple: ... bool runOnFunction(Function &F) override { vector<Instruction *> dels; dels.clear(); for (inst_iterator It = inst_begin(&F), Ie = inst_end(&F); It != Ie;) { Instruction *I = &*(It++); if (auto* op = dyn_cast<BinaryOperator>(I)) { IRBuilder<NoFolder>

Hi Thomson, the new call to puts() is inserted right away, whereas the old call to printf() is removed a bit later in SimplifyLibCalls::runOnFunction(). If you browse the code a bit and backtrack the call stack to see what happens with the return value of PrintFOpt::OptimizeFixedFormatString(), you will stumble upon this segment in SimplifyLibCalls.cpp:1703ff.: // Try to optimize this call.

Hi all, Sorry for the inconvenient about the previous post. The files were not attached. So I put them here again. I am a newbie in LLVM and I am trying to replace the function like: old function || new function ============================== ========= int haha(int a) { int haha(int a, char* ID) { ===> }

LLVM is built in Release mode. The version is 6.0.0. I think that a similar code worked on verison 3.9.0. It is probably a null pointer dereference occurring in eraseFromParent(). I checked and reconfirmed that the instruction had no uses. Perhaps I should rebuild LLVM. Thanks. On Wed, Aug 8, 2018 at 9:03 PM, mayuyu.io <admin at mayuyu.io> wrote: > Hmmmm that’s strange. Do you get an