Fix a crash for an edge case of the GNU ?: extension.

llvm-svn: 148923
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index db87cba..5c2061b 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -1999,6 +1999,8 @@
     return EmitAggExprToLValue(expr);
   }
 
+  OpaqueValueMapping binding(*this, expr);
+
   const Expr *condExpr = expr->getCond();
   bool CondExprBool;
   if (ConstantFoldsToSimpleInteger(condExpr, CondExprBool)) {
@@ -2009,8 +2011,6 @@
       return EmitLValue(live);
   }
 
-  OpaqueValueMapping binding(*this, expr);
-
   llvm::BasicBlock *lhsBlock = createBasicBlock("cond.true");
   llvm::BasicBlock *rhsBlock = createBasicBlock("cond.false");
   llvm::BasicBlock *contBlock = createBasicBlock("cond.end");
diff --git a/clang/test/CodeGenCXX/conditional-gnu-ext.cpp b/clang/test/CodeGenCXX/conditional-gnu-ext.cpp
index 46c5e7f..104a91d2 100644
--- a/clang/test/CodeGenCXX/conditional-gnu-ext.cpp
+++ b/clang/test/CodeGenCXX/conditional-gnu-ext.cpp
@@ -140,3 +140,11 @@
   }
 
 }
+
+namespace test4 {
+  // Make sure this doesn't crash.
+  void f() {
+    const int a = 10, b = 20;
+    const int *c = &(a ?: b);
+  }
+}