[c++20] Add CXXRewrittenBinaryOperator to represent a comparison
operator that is rewritten as a call to multiple other operators.

No functionality change yet: nothing creates these expressions.

llvm-svn: 375305
diff --git a/clang/lib/CodeGen/CGExprAgg.cpp b/clang/lib/CodeGen/CGExprAgg.cpp
index ab51512..2f0e493 100644
--- a/clang/lib/CodeGen/CGExprAgg.cpp
+++ b/clang/lib/CodeGen/CGExprAgg.cpp
@@ -150,6 +150,9 @@
   void VisitBinAssign(const BinaryOperator *E);
   void VisitBinComma(const BinaryOperator *E);
   void VisitBinCmp(const BinaryOperator *E);
+  void VisitCXXRewrittenBinaryOperator(CXXRewrittenBinaryOperator *E) {
+    Visit(E->getSemanticForm());
+  }
 
   void VisitObjCMessageExpr(ObjCMessageExpr *E);
   void VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) {