search for: setoperands

Hello, I am trying to reset the operands of instructions. What I am doing is, I am finding all Uses of a specific operand in an Instruction and resetting it with a new value using "setOperands(int, Value*)". I am doing as: for (auto vmitr=vm.begin(), vsitr=vs.begin(); vmitr!=vm.end() && vsitr!=vs.end(); vmitr++, vsitr++){ // I have two *Value ( operands) for ( auto myitr =(*vsitr)->user_begin(); myitr!=(*vsitr)->user_end(); ++myitr){ // Finding the uses of one operan...

John, you are right. I 'browsed' the doxygen's inheritance diagram. Shouldn't I then be able to cast Constant * to Value*? Plugging the retrieved Constant* (from ConstantExpr::getGetElementPtr) into Instruction->setOperand compiles, but gives me an assertion failure at runtime. I have no access to the code at the moment. I will gather more information possibly tomorrow.

> On Mar 19, 2020, at 2:31 PM, Johannes Doerfert <johannesdoerfert at gmail.com> wrote: > > I think addressing this issue first makes sense. I would however start > by determining the actual impact of different design choices here. I > mean, do we know locks will be heavily contented? If I had to guess I'd > say most passes will not create or modify functions nor add

> On Mar 20, 2020, at 12:34 PM, Nicholas Krause <xerofoify at gmail.com> wrote: > >> >> The problem isn’t constants or functions themselves, it is that they are instances of llvm::Value. Everything that walks a use/def list would have to run code that checks for this, and every call to inst->setOperand() would have to do locking or conditional locking. This would be

Hi, I'm learning to use the llvm API, but I got a question for which I haven't found a good answer yet: What is the best way to turn an unconditional branch into a conditional branch? All I want to do is add two more operands, a successor and a condition. But no matter how I try to do this any one of setCondition()/setOperand()/setSuccessor() causes an assertion like these: Cannot

Hi all, extracting datafields of globals, the API code ends up in a Constant * Constant* const_ptr_103 = ConstantExpr::getGetElementPtr(gvar_struct_foo, const_ptr_103_indices); it can be used to initialize e.g. a new instruction like: StoreInst* void_119 = new StoreInst(const_float_102, const_ptr_103, false, label_entry_113); But how about replacing the operand of an already existing

Sorry for the confusion, I pasted the code I fixed locally... Here is the code at top of the trunk: // load (select (cond, null, P)) -> load P if (Constant *C = dyn_cast<Constant>(SI->getOperand(1))) if (C->isNullValue()) { LI.setOperand(0, SI->getOperand(2)); return &LI; } So it is a bug? -----Original Message----- From:

Hi, I would like to understand better the meaning of constant null pointer in LLVM IR. Can the optimizer assume that dereferencing a null pointer is always unreachable? Or is it only the case for address space 0? Is it ok to have null pointer be a valid pointer for an address space other than 0? In InstCombine pass in InstCombiner::visitLoadInst(LoadInst &LI) I see that we replace load of

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

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>

Hello, I need to append something to the global "llvm.global_ctors". This variable may or may not already be declared within the current module. If I lookup the global variable, I see that it supports a getOperand(i) and setOperand(i,c), but does not support any way that I can enlarge that array to add a new record. Any suggestions? -- Nick Johnson

I have a MDNode, and one of its operand is an int. I'd like to assign a new int value to that operand during the llvm optimization. What is the right way to do this ? (There is no setOperand() with MDNode class.) Junjie

Hi all. Is it allowed to modify ConstantArray object within setOperand method, or it is better to leave old ConstantArray object and create new one? Thanks! -Stepan.

Hi all, I am trying to merge functions with the same debug location by using replaceAllUsesWith(). However, this leads to type unmatched problems because the functions with the same debug location can have different parameters. An example is foo(struct A) can be compiled to foo.1(struct A.1) and foo.2(struct A.2). I have inserted CastInst to solve the problems of arguments and return values type

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 =

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

Hi all, I can get access to the data stored in globals as follows: GlobalVariable* pGvarAct=_set_a_valid_global_; const_ptr_indicesVec=_the_indexes_ llvm::Constant* pConst; pConst=ConstantExpr::getGetElementPtr(pGvarAct, const_ptr_indicesVec); and e.g. use this to repalece an argumrnt of an instruction like: I->setOperand(someArgumentIndex,pConst); However, getGetElementPtr returns a

I am able to access the source operands of an instruction using either getOperand() or op_iterator, However, I can't find any method available for destination operand. Someone suggests that instruction itself can represent the destination operand. http://lists.cs.uiuc.edu/pipermail/llvmdev/2011-January/037518.html The getOperand() returns an unsigned value like 0x9063498, while I can't

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 now understand that IndVarSimplify.cpp is capable of reproducing array references when the pointer initialization from the array address is found inside the immediately enclosing loop, such that in the following code: int A[20000], B[100], Z; int main() { int i, j, *a, *b; for ( a = &A[0], i = 0; i != 200; i++ ) for ( b = &B[0], j = 0; j != 100; j++