PR7242: Make sure to use a different context for evaluating constant

initializers, so the result of the evaluation doesn't leak through
inconsistently.  Also, don't evaluate references to variables with
initializers with side-effects.

llvm-svn: 113128

2 files changed, 13 insertions, 1 deletions

diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 175fd85a244..7347f5a43e1 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -1008,8 +1008,11 @@ bool IntExprEvaluator::CheckReferencedDecl(const Expr* E, const Decl* D) {
 
         VD->setEvaluatingValue();
 
-        if (Visit(const_cast<Expr*>(Init))) {
+        Expr::EvalResult EResult;
+        if (Init->Evaluate(EResult, Info.Ctx) && !EResult.HasSideEffects &&
+            EResult.Val.isInt()) {
           // Cache the evaluated value in the variable declaration.
+          Result = EResult.Val;
           VD->setEvaluatedValue(Result);
           return true;
         }
diff --git a/clang/test/CodeGen/fold-const-declref.c b/clang/test/CodeGen/fold-const-declref.c
new file mode 100644
index 00000000000..5a7ba8e26a7
--- /dev/null
+++ b/clang/test/CodeGen/fold-const-declref.c
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -verify -emit-llvm-only
+
+// PR7242: Check that this doesn't crash.
+int main(void)
+{
+  int __negative = 1;
+  const int __max = __negative && 0 ;
+  __max / 0;
+}