Take __real/__imag operators into account in TBR analysis and Get…

…InnermostReturnExpr.

lib/Differentiator/CladUtils.cpp

@@ -576,6 +576,14 @@ namespace clad {
           auto opCode = UnOp->getOpcode();
           if (opCode == clang::UO_PreInc || opCode == clang::UO_PreDec)
             Visit(UnOp->getSubExpr());
+          else if (opCode == UnaryOperatorKind::UO_Real ||
+                   opCode == UnaryOperatorKind::UO_Imag) {
+            /// FIXME: Considering real/imaginary part atomic is
+            /// not always correct since the subexpression can
+            /// be more complex than just a DeclRefExpr.
+            /// (e.g. `__real (n++ ? z1 : z2)`)
+            m_Exprs.push_back(UnOp);
+          }
         }
 
         void VisitDeclRefExpr(clang::DeclRefExpr* DRE) {

lib/Differentiator/TBRAnalyzer.cpp

@@ -736,6 +736,11 @@ bool TBRAnalyzer::VisitUnaryOperator(clang::UnaryOperator* UnOp) {
       markLocation(innerExpr);
     }
   }
+  /// FIXME: Ideally, `__real` and `__imag` operators should be
+  /// treated as member expressions. However, it is not clear
+  /// where the FieldDecls of real and imaginary parts should be
+  /// deduced from (their names might be compiler-specific).
+  /// So for now we visit the whole subexpression.
   return true;
 }