Support CompoundLiteralExpr in the reverse mode

Fixes #1522

Author: PetroZarytskyi

include/clad/Differentiator/ReverseModeVisitor.h

@@ -371,6 +371,7 @@ namespace clad {
     StmtDiff VisitCallExpr(const clang::CallExpr* CE);
     virtual StmtDiff VisitCompoundStmt(const clang::CompoundStmt* CS);
     StmtDiff VisitConditionalOperator(const clang::ConditionalOperator* CO);
+    StmtDiff VisitCompoundLiteralExpr(const clang::CompoundLiteralExpr* CLE);
     StmtDiff VisitCXXBoolLiteralExpr(const clang::CXXBoolLiteralExpr* BL);
     StmtDiff VisitCXXBindTemporaryExpr(const clang::CXXBindTemporaryExpr* BTE);
     StmtDiff VisitCharacterLiteral(const clang::CharacterLiteral* CL);

lib/Differentiator/ReverseModeVisitor.cpp

@@ -714,6 +714,18 @@ Expr* ReverseModeVisitor::getStdInitListSizeExpr(const Expr* E) {
     return StmtDiff(Clone(S));
   }
 
+  StmtDiff
+  ReverseModeVisitor::VisitCompoundLiteralExpr(const CompoundLiteralExpr* CLE) {
+    StmtDiff result = Visit(CLE->getInitializer());
+    ParsedType PT = ParsedType::make(CLE->getType());
+    result.updateStmt(
+        m_Sema.ActOnCompoundLiteral(noLoc, PT, noLoc, result.getExpr()).get());
+    result.updateStmtDx(
+        m_Sema.ActOnCompoundLiteral(noLoc, PT, noLoc, result.getExpr_dx())
+            .get());
+    return result;
+  }
+
   StmtDiff ReverseModeVisitor::VisitCompoundStmt(const CompoundStmt* CS) {
     int scopeFlags = Scope::DeclScope;
     // If this is the outermost compound statement of the function,

test/Gradient/UserDefinedTypes.C

@@ -1285,6 +1285,17 @@ double fn34(double x, double y) {
 // CHECK-NEXT:    *_d_x += _d_obj_x.data;
 // CHECK-NEXT:}
 
+double fn35(double x, double y) {
+    double& ref = *(PtrAndValAggr){x, &y}.ptr;
+    return ref;
+}
+
+// CHECK:  void fn35_grad(double x, double y, double *_d_x, double *_d_y) {
+// CHECK-NEXT:      double &_d_ref = *(PtrAndValAggr){0., _d_y}.ptr;
+// CHECK-NEXT:      double &ref = *(PtrAndValAggr){x, &y}.ptr;
+// CHECK-NEXT:      _d_ref += 1;
+// CHECK-NEXT:  }
+
 void print(const Tangent& t) {
   for (int i = 0; i < 5; ++i) {
     printf("%.2f", t.data[i]);
@@ -1422,4 +1433,7 @@ int main() {
 
     INIT_GRADIENT(fn34);
     TEST_GRADIENT(fn34, /*numOfDerivativeArgs=*/2, -5, 6, &d_i, &d_j);    // CHECK-EXEC: {1.00, 2.00}
+
+    INIT_GRADIENT(fn35);
+    TEST_GRADIENT(fn35, /*numOfDerivativeArgs=*/2, -5, 6, &d_i, &d_j);    // CHECK-EXEC: {0.00, 1.00}
 }