[clang][Interp] Handle CXXNoexceptExprs

[cor3ntin]

clang/test/AST/Interp/literals.cpp

1037–1045

Can you either add tests with explicit expressions in the no except, or see if you can enable one of the existing test files?

[tbaeder]

clang/test/AST/Interp/literals.cpp

1037–1045

Turns out I can.

[tbaeder]

clang/lib/AST/Interp/ByteCodeExprGen.cpp

1203

Looks like this is wrong.

[tbaeder]

Always ignore the operand expression.

[cor3ntin]

LGTM, thanks

clang/lib/AST/Interp/ByteCodeExprGen.h

public:
   bool VisitCXXTemporaryObjectExpr(const CXXTemporaryObjectExpr *E);
   bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
   bool VisitTypeTraitExpr(const TypeTraitExpr *E);
   bool VisitLambdaExpr(const LambdaExpr *E);
   bool VisitPredefinedExpr(const PredefinedExpr *E);
   bool VisitCXXThrowExpr(const CXXThrowExpr *E);
   bool VisitCXXReinterpretCastExpr(const CXXReinterpretCastExpr *E);
   bool VisitSourceLocExpr(const SourceLocExpr *E);
+  bool VisitCXXNoexceptExpr(const CXXNoexceptExpr *E);
 
 protected:
   bool visitExpr(const Expr *E) override;
   bool visitDecl(const VarDecl *VD) override;
 
 protected:
   /// Emits scope cleanup instructions.
   void emitCleanup();

clang/lib/AST/Interp/ByteCodeExprGen.cpp

for (unsigned I = 0, N = R->getNumFields(); I != N; ++I) {
     if (!this->emitInitField(FieldT, F->Offset, E))
       return false;
   }
 
   // Leave the pointer to the global on the stack.
   return true;
 }
 
+template <class Emitter>
+bool ByteCodeExprGen<Emitter>::VisitCXXNoexceptExpr(const CXXNoexceptExpr *E) {
+  assert(E->getType()->isBooleanType());
+  const Expr *Operand = E->getOperand();
+
+  if (DiscardResult)
+    return this->discard(Operand);
+  return this->emitConstBool(E->getValue(), E);
+}
+
 template <class Emitter> bool ByteCodeExprGen<Emitter>::discard(const Expr *E) {
   if (E->containsErrors())
     return false;
 
   OptionScope<Emitter> Scope(this, /*NewDiscardResult=*/true);
   return this->Visit(E);
 }
 

clang/test/AST/Interp/literals.cpp

namespace PointerCasts {
   constexpr intptr_t A = (intptr_t)P; // ref-error {{must be initialized by a constant expression}} \
                                       // ref-note {{cast that performs the conversions of a reinterpret_cast}} \
                                       // expected-error {{must be initialized by a constant expression}} \
                                       // expected-note {{cast that performs the conversions of a reinterpret_cast}}
 
   int array[(long)(char*)0]; // ref-warning {{variable length array folded to constant array}} \
                              // expected-warning {{variable length array folded to constant array}}
 }
+
+namespace NE {
+  constexpr int foo() noexcept {
+    return 1;
+  }
+  static_assert(noexcept(foo()), "");
+  constexpr int foo2() {
+    return 1;
+  }
+  static_assert(!noexcept(foo2()), "");
+}

clang/test/SemaCXX/cxx0x-noexcept-expression.cpp

 // RUN: %clang_cc1 -fsyntax-only -verify -std=c++2a %s -fexceptions -fcxx-exceptions -Wno-unevaluated-expression
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++2a %s -fexceptions -fcxx-exceptions -Wno-unevaluated-expression -fexperimental-new-constant-interpreter
 
 void f(); // expected-note {{possible target for call}}
 void f(int); // expected-note {{possible target for call}}
 
 void g() {
   bool b = noexcept(f); // expected-error {{reference to overloaded function could not be resolved; did you mean to call it with no arguments?}}
   bool b2 = noexcept(f(0));
 }