Add a unit test to verifies that attribute uniquing works so it doesn't break again.

The folding set details can be subtle and broke twice in the last couple of weeks.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172313 91177308-0d34-0410-b5e6-96231b3b80d8

unittests/IR/AttributesTest.cpp

@@ -0,0 +1,34 @@
+//===- llvm/unittest/IR/AttributesTest.cpp - Attributes unit tests --------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/IR/Attributes.h"
+#include "llvm/IR/LLVMContext.h"
+#include "gtest/gtest.h"
+using namespace llvm;
+
+namespace {
+
+TEST(Attributes, Uniquing) {
+  LLVMContext C;
+
+  Attribute AttrA = Attribute::get(C, Attribute::AlwaysInline);
+  Attribute AttrB = Attribute::get(C, Attribute::AlwaysInline);
+  EXPECT_EQ(AttrA, AttrB);
+
+  AttributeWithIndex AWIs[] = {
+    AttributeWithIndex::get(C, 1, Attribute::ZExt),
+    AttributeWithIndex::get(C, 2, Attribute::SExt)
+  };
+
+  AttributeSet SetA = AttributeSet::get(C, AWIs);
+  AttributeSet SetB = AttributeSet::get(C, AWIs);
+  EXPECT_EQ(SetA, SetB);
+}
+
+} // end anonymous namespace

unittests/IR/CMakeLists.txt

@@ -5,6 +5,7 @@ set(LLVM_LINK_COMPONENTS
   )
 
 set(IRSources
+  AttributesTest.cpp
   ConstantsTest.cpp
   DominatorTreeTest.cpp
   IRBuilderTest.cpp