Make one of the AttributeSet ctors maintain the invariant that the
attribute list is ordered by index.

Differential Revision: http://llvm-reviews.chandlerc.com/D1265

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187682 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/unittests/IR/AttributesTest.cpp b/unittests/IR/AttributesTest.cpp
index 2368bdf..ebcb772 100644
--- a/unittests/IR/AttributesTest.cpp
+++ b/unittests/IR/AttributesTest.cpp
@@ -31,4 +31,17 @@
   EXPECT_EQ(SetA, SetB);
 }
 
+TEST(Attributes, Ordering) {
+  LLVMContext C;
+
+  AttributeSet ASs[] = {
+    AttributeSet::get(C, 2, Attribute::ZExt),
+    AttributeSet::get(C, 1, Attribute::SExt)
+  };
+
+  AttributeSet SetA = AttributeSet::get(C, ASs);
+  AttributeSet SetB = SetA.removeAttributes(C, 1, ASs[1]);
+  EXPECT_NE(SetA, SetB);
+}
+
 } // end anonymous namespace