From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Mon, 7 Nov 2011 03:22:51 +0000 (+0000)
Subject: Allow constexpr variables' initializers to be folded in C++11 mode. This
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=cd689927139d3ab52c0c088521633c661bd2d807;p=clang

Allow constexpr variables' initializers to be folded in C++11 mode. This
partially undoes the revert in r143491, but does not introduce any new instances
of the underlying issue (which is not yet fixed) in code which does not use
the 'constexpr' keyword.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@143905 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp
index 9c9e473f7b..6456376d48 100644
--- a/lib/AST/ExprConstant.cpp
+++ b/lib/AST/ExprConstant.cpp
@@ -558,12 +558,14 @@ bool HandleLValueToRValueConversion(EvalInfo &Info, QualType Type,
     // them are not permitted.
     const VarDecl *VD = dyn_cast<VarDecl>(D);
     QualType VT = VD->getType();
-    if (!VD)
+    if (!VD || VD->isInvalidDecl())
       return false;
     if (!isa<ParmVarDecl>(VD)) {
       if (!IsConstNonVolatile(VT))
         return false;
-      if (!VT->isIntegralOrEnumerationType() && !VT->isRealFloatingType())
+      // FIXME: Allow folding of values of any literal type in all languages.
+      if (!VT->isIntegralOrEnumerationType() && !VT->isRealFloatingType() &&
+          !VD->isConstexpr())
         return false;
     }
     if (!EvaluateVarDeclInit(Info, VD, Frame, RVal))
diff --git a/test/SemaCXX/constant-expression-cxx11.cpp b/test/SemaCXX/constant-expression-cxx11.cpp
index 782b6a1d5b..92159a7b6a 100644
--- a/test/SemaCXX/constant-expression-cxx11.cpp
+++ b/test/SemaCXX/constant-expression-cxx11.cpp
@@ -135,7 +135,6 @@ namespace ParameterScopes {
 
 }
 
-#if 0
 namespace Pointers {
 
   constexpr int f(int n, const int *a, const int *b, const int *c) {
@@ -165,10 +164,9 @@ namespace FunctionPointers {
 
   static_assert_fold(1 + Apply(Select(4), 5) + Apply(Select(3), 7) == 42, "");
 
-  constexpr int Invalid = Apply(Select(0), 0); // xpected-error {{must be initialized by a constant expression}}
+  constexpr int Invalid = Apply(Select(0), 0); // expected-error {{must be initialized by a constant expression}}
 
 }
-#endif
 
 namespace PointerComparison {
 
@@ -211,12 +209,10 @@ static_assert_fold(&x >= &x, "");
 static_assert_fold(&x < &x, "false"); // expected-error {{false}}
 static_assert_fold(&x > &x, "false"); // expected-error {{false}}
 
-#if 0
 constexpr S* sptr = &s;
 // FIXME: This is not a constant expression; check we reject this and move this
 // test elsewhere.
 constexpr bool dyncast = sptr == dynamic_cast<S*>(sptr);
-#endif
 
 extern char externalvar[];
 // FIXME: This is not a constant expression; check we reject this and move this