[PATCH] Add two helper functions: isAtLeastAcquire, isAtLeastRelease

[Philip Reames]

With minor nitpicks, LGTM.

================
Comment at: include/llvm/IR/Instructions.h:53
@@ -52,1 +52,3 @@
 
+namespace {
+/// Returns true if the ordering is at least as strong as acquire
----------------
You should drop the anon namespace here. 

================
Comment at: include/llvm/IR/Instructions.h:57
@@ +56,3 @@
+inline bool isAtLeastAcquire(AtomicOrdering Ord) {
+   return (Ord == Acquire
+    || Ord == AcquireRelease
----------------
Stylistic: 
"( A ||
    B)"

Neither is "better", but this is the norm in LLVM code.  Please follow it.

http://reviews.llvm.org/D4844