Author: rsmith Date: Wed May 25 17:06:25 2016 New Revision: 270774 URL: http://llvm.org/viewvc/llvm-project?rev=270774&view=rev Log: Fix rejects-valid on constexpr function that accesses a not-yet-defined 'extern const' variable. That variable might be defined as 'constexpr', so we cannot prove that a use of it could never be a constant expression.
Modified: cfe/trunk/lib/AST/ExprConstant.cpp cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp Modified: cfe/trunk/lib/AST/ExprConstant.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprConstant.cpp?rev=270774&r1=270773&r2=270774&view=diff ============================================================================== --- cfe/trunk/lib/AST/ExprConstant.cpp (original) +++ cfe/trunk/lib/AST/ExprConstant.cpp Wed May 25 17:06:25 2016 @@ -2706,7 +2706,11 @@ static CompleteObject findCompleteObject } } else { // FIXME: Allow folding of values of any literal type in all languages. - if (Info.getLangOpts().CPlusPlus11) { + if (Info.checkingPotentialConstantExpression() && + VD->getType().isConstQualified() && !VD->hasDefinition(Info.Ctx)) { + // The definition of this variable could be constexpr. We can't + // access it right now, but may be able to in future. + } else if (Info.getLangOpts().CPlusPlus11) { Info.Diag(E, diag::note_constexpr_ltor_non_constexpr, 1) << VD; Info.Note(VD->getLocation(), diag::note_declared_at); } else { @@ -5456,8 +5460,9 @@ bool RecordExprEvaluator::VisitInitListE } auto *CXXRD = dyn_cast<CXXRecordDecl>(RD); - Result = APValue(APValue::UninitStruct(), CXXRD ? CXXRD->getNumBases() : 0, - std::distance(RD->field_begin(), RD->field_end())); + if (Result.isUninit()) + Result = APValue(APValue::UninitStruct(), CXXRD ? CXXRD->getNumBases() : 0, + std::distance(RD->field_begin(), RD->field_end())); unsigned ElementNo = 0; bool Success = true; Modified: cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp?rev=270774&r1=270773&r2=270774&view=diff ============================================================================== --- cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp (original) +++ cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp Wed May 25 17:06:25 2016 @@ -1181,6 +1181,20 @@ namespace ExternConstexpr { constexpr int j = 0; constexpr int k; // expected-error {{default initialization of an object of const type}} } + + extern const int q; + constexpr int g() { return q; } + constexpr int q = g(); + static_assert(q == 0, "zero-initialization should precede static initialization"); + + extern int r; // expected-note {{here}} + constexpr int h() { return r; } // expected-error {{never produces a constant}} expected-note {{read of non-const}} + + struct S { int n; }; + extern const S s; + constexpr int x() { return s.n; } + constexpr S s = {x()}; + static_assert(s.n == 0, "zero-initialization should precede static initialization"); } namespace ComplexConstexpr { _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits