Refactoring and test for r143360. Support for array rvalue to pointer decay is

needed for C++11, and will follow later.

llvm-svn: 143363

2 files changed, 9 insertions, 3 deletions

diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index a12beb51792..b34b59d9079 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -1222,10 +1222,13 @@ bool PointerExprEvaluator::VisitCastExpr(const CastExpr* E) {
     }
   }
   case CK_ArrayToPointerDecay:
+    // FIXME: Support array-to-pointer decay on array rvalues.
+    if (!SubExpr->isGLValue())
+      return Error(E);
+    return EvaluateLValue(SubExpr, Result, Info);
+
   case CK_FunctionToPointerDecay:
-    if (SubExpr->isGLValue() || SubExpr->getType()->isFunctionType())
-      return EvaluateLValue(SubExpr, Result, Info);
-    return Error(E);
+    return EvaluateLValue(SubExpr, Result, Info);
   }
 
   return ExprEvaluatorBaseTy::VisitCastExpr(E);
diff --git a/clang/test/Sema/const-eval.c b/clang/test/Sema/const-eval.c
index 8cfa7ea6f87..df56b06e48c 100644
--- a/clang/test/Sema/const-eval.c
+++ b/clang/test/Sema/const-eval.c
@@ -92,3 +92,6 @@ double d2 = ++d; // expected-error {{not a compile-time constant}}
 
 int n = 2;
 int intLvalue[*(int*)((long)&n ?: 1)] = { 1, 2 }; // expected-error {{variable length array}}
+
+union u { int a; char b[4]; };
+char c = ((union u)(123456)).b[0]; // expected-error {{not a compile-time constant}}