LLVM Value sign

Question

I'm having some problems when loading values. Here's a simple example of the IR that my compiler generates to show the problem:

define i32 @main() {

    entry:  
    %a = alloca i32          ; <i32*> [#uses=2]  
    store i32 1, i32* %a  
    %r = load i32* %a        ; <i32> [#uses=1]

    br label %Return

    Return:                  ; preds = %entry  
    ret i32 %r

}

but instead of return 1 it returns 16777216. I have tested the program with different values and it seems that it's a matter of internal binary representation of integer values.

Edited: I show you the trace of calls to llvm that my compiler makes to generate the code above. bloques.back().last is of type Value* and bloques.back().bl is BasicBlock* (the current Block)

bloques.back().last = dyn_cast<Value>(ConstantInt::get(
    Type::getInt32Ty(getGlobalContext()), $1, true)); // $1 is an int
AllocaInst *alloc = new AllocaInst(
    Type::getInt32Ty(getGlobalContext()), izq.c_str(), bloques.back().bl);
Value *derecha = bloques.back().last;
StoreInst *s = new StoreInst(derecha, alloc, false, bloques.back().bl);
bloques.back().last = alloc;
LoadInst* v1 = new LoadInst(bloques.back().last, "r", false, bloques.back().bl);
bloques.back().last = v1;
BasicBlock* blockReturn = BasicBlock::Create(getGlobalContext(), "Return", Main);
Value* last = bloques.back().last;
BranchInst::Create(blockReturn, bloques.back().bl);
ReturnInst::Create(getGlobalContext(), last, blockReturn);

The source code corresponding to the IR representation would be:

a = 1
return a

Edit2: In my main function after generate the code and before start the execution via JIT I do this:

ExecutionEngine *EE = EngineBuilder(M).create();
string str = EE->getTargetData()->getStringRepresentation();
str[0] = 'e';
M->setDataLayout(str);

if (verifyModule(*M)) {
   errs() << argv[0] << ": Error building the function!\n";
   return 1;
}

vector<GenericValue> noargs;
GenericValue GV = EE->runFunction(Main, noargs);

outs() << "Result: " << GV.IntVal << "\n";
return 0;

Solved: finally i've found the solution. To change the endianness I do the following (a little spaguetti but it works):

Module *M = new Module("pythoncode", getGlobalContext());
ExecutionEngine *EE2 = EngineBuilder(M).create();
string str = EE2->getTargetData()->getStringRepresentation();
str[0] = 'e';
cout << str << endl;
M->setDataLayout(str);
ExecutionEngine *EE = EngineBuilder(M).create();

Thanks in advance.

Santos Merino.