gistfile1.cpp

llvm::Value *Runner::emitToLower(llvm::Value *value)
{
#if 1 == 0 // {{{ C equivalent
    return value >= 'A' && value <= 'Z'
        ? value + 32 
        : value;
#endif // }}}

    // IR:
    //   %off = add %ch, -65
    //   %lwr = add %ch, 32
    //   %cnd = icmp ult %off, 26
    //   %result = select %cnd, %off, %lwr

    llvm::Value *offset = builder_.CreateAdd(value, llvm::ConstantInt::get(value->getType(), -65));
    llvm::Value *lwr = builder_.CreateAdd(value, llvm::ConstantInt::get(value->getType(), 32));
    llvm::Value *cnd = builder_.CreateICmpULT(offset, llvm::ConstantInt::get(value->getType(), 26));
    llvm::Value *result = builder_.CreateSelect(cnd, offset, lwr);

    return result;
}