Revert r347417 "Re-Reinstate 347294 with a fix for the failures."

Kept the "indirect_builtin_constant_p" test case in test/SemaCXX/constant-expression-cxx1y.cpp
while we are investigating why the following snippet fails:

  extern char extern_var;
  struct { int a; } a = {__builtin_constant_p(extern_var)};

llvm-svn: 348039
diff --git a/clang/lib/Sema/AnalysisBasedWarnings.cpp b/clang/lib/Sema/AnalysisBasedWarnings.cpp
index 3b6cbe9..ab46554 100644
--- a/clang/lib/Sema/AnalysisBasedWarnings.cpp
+++ b/clang/lib/Sema/AnalysisBasedWarnings.cpp
@@ -1309,10 +1309,11 @@
     case Stmt::ObjCForCollectionStmtClass:
       return true;
     case Stmt::DoStmtClass: {
-      Expr::EvalResult Result;
-      if (!cast<DoStmt>(S)->getCond()->EvaluateAsInt(Result, Ctx))
+      const Expr *Cond = cast<DoStmt>(S)->getCond();
+      llvm::APSInt Val;
+      if (!Cond->EvaluateAsInt(Val, Ctx))
         return true;
-      return Result.Val.getInt().getBoolValue();
+      return Val.getBoolValue();
     }
     default:
       break;