Fix bug in attribute(nonnull) processing where not all of the parameter indices in nonnull(...) were actually processed.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@60546 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index 2e6108c..bff650d 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -313,7 +313,7 @@
     
     
     // The argument must be an integer constant expression.
-    Expr *Ex = static_cast<Expr *>(Attr.getArg(0));
+    Expr *Ex = static_cast<Expr *>(*I);
     llvm::APSInt ArgNum(32);
     if (!Ex->isIntegerConstantExpr(ArgNum, S.Context)) {
       S.Diag(Attr.getLoc(), diag::err_attribute_argument_not_int)