updating __qpu__ macro to contain annotation attribute

Signed-off-by: Alex McCaskey <mccaskeyaj@ornl.gov>

xacc/compiler/qalloc.cpp

@@ -10,7 +10,7 @@ template <typename T> struct empty_delete {
 qreg::qreg(const int n) { buffer = xacc::qalloc(n).get(); }
 qreg::qreg(const qreg &other) : buffer(other.buffer) {}
 
-int qreg::operator[](const int &i) { return 0; }
+int qreg::operator[](const int &i) { return i; }
 AcceleratorBuffer *qreg::results() { return buffer; }
 std::map<std::string, int> qreg::counts() {
   return buffer->getMeasurementCounts();

xacc/compiler/qalloc.hpp

@@ -49,6 +49,8 @@ xacc::internal_compiler::qreg qalloc(const int n) {
   return xacc::internal_compiler::qreg(n);
 }
 
-#define __qpu__ [[clang::syntax(qcor)]]
+// __qpu__ indicates this functions is for the QCOR Clang Syntax Handler
+// and annotated with quantum for the LLVM IR CodeGen
+#define __qpu__ [[clang::syntax(qcor)]] __attribute__((annotate("quantum")))
 
 #endif
\ No newline at end of file