[LLVMdev] <badref> showed up when duplicating a list of dependent instructions

[Chuck Zhao]

I collected a sequence of LLVM instructions, want to make a copy of each 
and insert them into a PREVIOUS location inside the same function (all 
globals and locals are properly declared before the PREVIOUS location).

Here is the list of instructions I want to duplicate and insert:

0    %90 = load i32* @strstart, align 4
1    %91 = add i32 %90, 2
2    %88 = load i32* @ins_h, align 4
3    %92 = getelementptr inbounds [65536 x i8]* @window, i32 0, i32 %91
4    %89 = shl i32 %88, 5
5    %93 = load i8* %92, align 1
6    %.masked = and i32 %89, 32736
7    %94 = zext i8 %93 to i32
8    %95 = xor i32 %94, %.masked
9    %.sum73 = or i32 %95, 32768
10    %104 = getelementptr inbounds [65536 x i16]* @prev, i32 0, i32 %.sum73
11    %take_addr2 = getelementptr i16* %104
12    %105 = bitcast i16* %take_addr2 to i8*
13    call void @bkp_memory(i8* %105, i32 2)

{basically, I want to duplicate the bkp_memory() call, everything else 
are its dependent instructions.}

I put them into a std::vector<Instruction *> coll, with the following 
code trying to do the replication and insertion:

std::vector<Instruction *>::iterator p;
Instruction * pi = PREVIOUS_POSITION;
BasicBlock * pb = PREVIOUS_POSITION->getParent();

for(p = coll.begin(); p != coll.end(); ++p){
    Instruction * CurI = * p;
    Instruction * CloneI = CurI->clone();
    CloneI->setName(CurI->getName());
    errs() << *CloneI << "\n";
    pb->getInstList().insertAfter(pi, CloneI); // Inserts newInst after 
pi in pb

    // adjust pi: point to the newly inserted inst:
    pi = CurI;

}//end of for loop on p


However, I got the following errors:

--- Insert New (cloned) Instructions: ...
   <badref>  = load i32* @strstart, align 4
   <badref>  = add i32<badref>, 2
   <badref>  = load i32* @ins_h, align 4
   <badref>  = getelementptr inbounds [65536 x i8]* @window, i32 0, i32<badref>
   <badref>  = shl i32<badref>, 5
   <badref>  = load i8*<badref>, align 1
   %.masked = and i32<badref>, 32736
   <badref>  = zext i8<badref>  to i32
   <badref>  = xor i32<badref>, %.masked
   %.sum73 = or i32<badref>, 32768
   <badref>  = getelementptr inbounds [65536 x i16]* @prev, i32 0, i32 %.sum73
   %take_addr2 = getelementptr i16*<badref>
   <badref>  = bitcast i16* %take_addr2 to i8*
   call void @bkp_memory(i8*<badref>, i32 2)
Instruction does not dominate all uses!
   %95 = add i32 %93, 2
   %90 = getelementptr inbounds [65536 x i8]* @window, i32 0, i32 %95
Instruction does not dominate all uses!
   %97 = getelementptr inbounds [65536 x i8]* @window, i32 0, i32 %95
   %92 = load i8* %97, align 1
Instruction does not dominate all uses!
   %.masked = and i32 %91, 32736
   %101 = xor i32 %100, %.masked
Broken module found, compilation aborted!


What am I doing wrong here?
Does the<badref>  sound alarm to anyone?
What is the right approach I should take here?


Thank you very much

Chuck




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