constexpr: Implement the [dcl.constexpr]p5 check for whether a constexpr

function definition can produce a constant expression. This also provides the
last few checks for [dcl.constexpr]p3 and [dcl.constexpr]p4.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@149108 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 9 insertions, 0 deletions

diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index b710a20831..9221b89b1a 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -972,6 +972,15 @@ bool Sema::CheckConstexprFunctionBody(const FunctionDecl *Dcl, Stmt *Body) {
     }
   }
 
+  llvm::SmallVector<PartialDiagnosticAt, 8> Diags;
+  if (!Expr::isPotentialConstantExpr(Dcl, Diags)) {
+    Diag(Dcl->getLocation(), diag::err_constexpr_function_never_constant_expr)
+      << isa<CXXConstructorDecl>(Dcl);
+    for (size_t I = 0, N = Diags.size(); I != N; ++I)
+      Diag(Diags[I].first, Diags[I].second);
+    return false;
+  }
+
   return true;
 }