[LLVMdev] Instruction does not dominate all uses! <badref> ??

[edA-qa mort-ora-y]

Okay, I've think I understand now. By using a "Value" object (like a
function call) in another instruction does nothing more than use a
reference to that value. It is still my responsibility to ensure that
value/reference is actually created prior to its use in the block.

On 02/11/12 12:16, Nick Lewycky wrote:
> edA-qa mort-ora-y wrote:
>> I'm having trouble figuring out what the error "Instruction does not
>> dominate all uses!" means. I'm trying to construct a call to a function
>> with two parameters. The printed IR, with error, looks like this:
>>
>> define i32 @add(i32, i32) {
>> EntryBlock:
>>    %2 = add i32 %0, %1
>>    ret i32 %2
>> }
>>
>> define i32 @eval_expr() {
>> EntryBlock:
>>    ret i32<badref>
>> }
>>
>> Instruction does not dominate all uses!
>>    <badref>  = call i32 @add(i32 2, i32 3)
>>    ret i32<badref>
> 
> It's correct but not entirely helpful. You've got an instruction in
> function @eval_expr whose operand is an instruction in an entirely
> different function (or in no function at all).
> 
>> And the approximate/simplified code I'm using to generate the call,
>> which would appear at<badref>  is:
>>
>>     llvm::Value * func = module->getFunction( "add" );
>>     
>>     std::vector<llvm::Value*>  args;
>>     args.push_back( llvm::ConstantInt::get( llvm::Type::getInt32Ty(
>> *context ), 2 ) );
>>     args.push_back( llvm::ConstantInt::get( llvm::Type::getInt32Ty(
>> *context ), 3 ) );
>>     
>>     llvm::ArrayRef<llvm::Value*>  ar_args( args );
>>     return llvm::CallInst::Create( func, ar_args );
> 
> This creates a CallInst but doesn't insert it into any basic block.
> 
> Nick
> 
> 


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edA-qa mort-ora-y
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