PR11926 + duplicates: Fix crash in -Wuninitialized when using a compiler like

g++4.7, which reuses stack space allocated for temporaries. CFGElement::getAs
returns a suitably-cast version of 'this'. Patch by Markus Trippelsdorf!

No test: this code has the same observable behavior as the old code when built
with most compilers, and the tests were already failing when built with a
compiler for which this produced a broken binary.

llvm-svn: 155803

clang/lib/Analysis/UninitializedValues.cpp

@@ -168,7 +168,8 @@ static const BinaryOperator *getLogicalOperatorInChain(const CFGBlock *block) {
   if (block->empty())
     return 0;
 
-  const CFGStmt *cstmt = block->front().getAs<CFGStmt>();
+  CFGElement front = block->front();
+  const CFGStmt *cstmt = front.getAs<CFGStmt>();
   if (!cstmt)
     return 0;