[clang][Interp] Reject compound assign operators pre-C++14

Author: tbaederr

clang/lib/AST/Interp/ByteCodeExprGen.cpp

@@ -1834,6 +1834,9 @@ bool ByteCodeExprGen<Emitter>::VisitCompoundAssignOperator(
   std::optional<PrimType> RT = classify(RHS->getType());
   std::optional<PrimType> ResultT = classify(E->getType());
 
+  if (!Ctx.getLangOpts().CPlusPlus14)
+    return this->visit(RHS) && this->visit(LHS) && this->emitError(E);
+
   if (!LT || !RT || !ResultT || !LHSComputationT)
     return false;
 

clang/test/SemaCXX/for-range-examples.cpp

@@ -1,4 +1,5 @@
 // RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++11
+// RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++11 -fexperimental-new-constant-interpreter
 
 namespace value_range_detail {
   template<typename T>

clang/test/SemaCXX/integer-overflow.cpp

@@ -1,6 +1,10 @@
 // RUN: %clang_cc1 %s -verify -fsyntax-only -std=gnu++98 -triple x86_64-pc-linux-gnu
 // RUN: %clang_cc1 %s -verify -fsyntax-only -std=gnu++2a -triple x86_64-pc-linux-gnu
 
+// RUN: %clang_cc1 %s -verify -fsyntax-only -std=gnu++98 -triple x86_64-pc-linux-gnu -fexperimental-new-constant-interpreter
+// RUN: %clang_cc1 %s -verify -fsyntax-only -std=gnu++2a -triple x86_64-pc-linux-gnu -fexperimental-new-constant-interpreter
+
+
 typedef unsigned long long uint64_t;
 typedef unsigned int uint32_t;