Fix an issue with the IR sink pass found by inspection.  (I'm not sure anyone is actually using this, but might as well fix it since I found the issue.)

llvm-svn: 138965
diff --git a/llvm/test/Transforms/Sink/basic.ll b/llvm/test/Transforms/Sink/basic.ll
index 54b7f13..81782e9 100644
--- a/llvm/test/Transforms/Sink/basic.ll
+++ b/llvm/test/Transforms/Sink/basic.ll
@@ -20,3 +20,19 @@
 false:
   ret i32 0
 }
+
+; But don't sink volatile loads...
+
+;      CHECK: @foo2
+;      CHECK: volatile load
+; CHECK-NEXT: store i32
+
+define i32 @foo2(i1 %z) {
+  %l = volatile load i32* @A
+  store i32 0, i32* @B
+  br i1 %z, label %true, label %false
+true:
+  ret i32 %l
+false:
+  ret i32 0
+}