Pending clear answer from WG21 on whether core issue 903 is intended to apply to

C++11 or just C++17, restrict the set of null pointer constants in C++11 mode
back to those which were considered null in C++98.

llvm-svn: 150510

1 files changed, 11 insertions, 4 deletions

diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index 5d22d144f48..5b511cc8831 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -2728,11 +2728,18 @@ Expr::isNullPointerConstant(ASTContext &Ctx,
     return NPCK_NotNull;
 
   // If we have an integer constant expression, we need to *evaluate* it and
-  // test for the value 0.
-  llvm::APSInt Result;
-  bool IsNull = isIntegerConstantExpr(Result, Ctx) && Result == 0;
+  // test for the value 0. Don't use the C++11 constant expression semantics
+  // for this, for now; once the dust settles on core issue 903, we might only
+  // allow a literal 0 here in C++11 mode.
+  if (Ctx.getLangOptions().CPlusPlus0x) {
+    if (!isCXX98IntegralConstantExpr(Ctx))
+      return NPCK_NotNull;
+  } else {
+    if (!isIntegerConstantExpr(Ctx))
+      return NPCK_NotNull;
+  }
 
-  return (IsNull ? NPCK_ZeroInteger : NPCK_NotNull);
+  return (EvaluateKnownConstInt(Ctx) == 0) ? NPCK_ZeroInteger : NPCK_NotNull;
 }
 
 /// \brief If this expression is an l-value for an Objective C