llvm dev - Jun 2006 - [LLVMdev] instruction sequence

I'm trying to insert a call to fprintf(stderr, ...).  I've looked at
the emitted assembly from llvm-gcc, and it consists of a LoadInst (of
stderr) and CallInst.  It looks like this:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
	%tmp.1 = load %struct._IO_FILE** %stderr		 ; ty=%struct._IO_FILE*
	%tmp.0 = call int (%struct._IO_FILE*, sbyte*, ...)* %fprintf(%struct._IO_FILE*
%tmp.1, sbyte* getelementptr ([6 x sbyte]* %.str_1, int 0, int 0))		 ; ty=int
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

I essentially modified the code example from Ryan Lefever's post on
May 1, 2006.  Here's a snippet of my code:

****************************************
   Constant* constStr = ConstantArray::get("test\n");
   GlobalVariable* gv = new GlobalVariable
     (constStr->getType(), true, GlobalValue::InternalLinkage, constStr,
      "", MP);
   std::vector<Constant*> geplist;
   geplist.push_back(ConstantUInt::get(Type::UIntTy,0));
   geplist.push_back(ConstantUInt::get(Type::UIntTy,0));
   Constant* gep = ConstantExpr::getGetElementPtr(gv,geplist);

   IP = new LoadInst(GVstderr, "loadstderr", IP);
   IPstderr = IP;

   std::vector<Value*> args;
   args.push_back(IPstderr);
   args.push_back(gep);

   IP = new CallInst(F, args, "", IP);
****************************************

However, I'm getting the following error message:

----------------------------------------
Instruction does not dominate all uses!
        %loadstderr = load %struct._IO_FILE** %stderr           ;
<%struct._IO_FILE*> [#uses=1]
        call int (%struct._IO_FILE*, sbyte*, ...)* %fprintf( %struct._IO_FILE*
%loadstderr, sbyte* getelementptr ([6 x sbyte]* %0, uint 0, uint 0) )          
; <int>:0 [#uses=0]
Broken module found, compilation aborted!
----------------------------------------

Can someone tell me what I'm doing wrong?  Thanks.

-- 
Jerry Hom

On Fri, 30 Jun 2006, Jerry Hom wrote:
>   IP = new LoadInst(GVstderr, "loadstderr", IP);
>   IPstderr = IP;
This creates a load, inserting it before "IP".  It then sets IP to the
load.
>   std::vector<Value*> args;
>   args.push_back(IPstderr);
>   args.push_back(gep);
>
>   IP = new CallInst(F, args, "", IP);
This creates a call, inserting it before IP (the load), which is the 
problem.  If you don't modify IP when you insert the load, it should work.

-Chris
> ****************************************
>
> However, I'm getting the following error message:
>
> ----------------------------------------
> Instruction does not dominate all uses!
>        %loadstderr = load %struct._IO_FILE** %stderr           ;
<%struct._IO_FILE*> [#uses=1]
>        call int (%struct._IO_FILE*, sbyte*, ...)* %fprintf(
%struct._IO_FILE* %loadstderr, sbyte* getelementptr ([6 x sbyte]* %0, uint 0,
uint 0) )           ; <int>:0 [#uses=0]
> Broken module found, compilation aborted!
> ----------------------------------------
>
> Can someone tell me what I'm doing wrong?  Thanks.
>
>
-Chris

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