NFC: make AtomicOrdering an enum class
Summary:
In the context of http://wg21.link/lwg2445 C++ uses the concept of
'stronger' ordering but doesn't define it properly. This should be fixed
in C++17 barring a small question that's still open.
The code currently plays fast and loose with the AtomicOrdering
enum. Using an enum class is one step towards tightening things. I later
also want to tighten related enums, such as clang's
AtomicOrderingKind (which should be shared with LLVM as a 'C++ ABI'
enum).
This change touches a few lines of code which can be improved later, I'd
like to keep it as NFC for now as it's already quite complex. I have
related changes for clang.
As a follow-up I'll add:
bool operator<(AtomicOrdering, AtomicOrdering) = delete;
bool operator>(AtomicOrdering, AtomicOrdering) = delete;
bool operator<=(AtomicOrdering, AtomicOrdering) = delete;
bool operator>=(AtomicOrdering, AtomicOrdering) = delete;
This is separate so that clang and LLVM changes don't need to be in sync.
Reviewers: jyknight, reames
Subscribers: jyknight, llvm-commits
Differential Revision: http://reviews.llvm.org/D18775
llvm-svn: 265602
diff --git a/llvm/lib/Transforms/Utils/GlobalStatus.cpp b/llvm/lib/Transforms/Utils/GlobalStatus.cpp
index 3893a75..8be42ae 100644
--- a/llvm/lib/Transforms/Utils/GlobalStatus.cpp
+++ b/llvm/lib/Transforms/Utils/GlobalStatus.cpp
@@ -20,11 +20,11 @@
/// and release, then return AcquireRelease.
///
static AtomicOrdering strongerOrdering(AtomicOrdering X, AtomicOrdering Y) {
- if (X == Acquire && Y == Release)
- return AcquireRelease;
- if (Y == Acquire && X == Release)
- return AcquireRelease;
- return (AtomicOrdering)std::max(X, Y);
+ if (X == AtomicOrdering::Acquire && Y == AtomicOrdering::Release)
+ return AtomicOrdering::AcquireRelease;
+ if (Y == AtomicOrdering::Acquire && X == AtomicOrdering::Release)
+ return AtomicOrdering::AcquireRelease;
+ return (AtomicOrdering)std::max((unsigned)X, (unsigned)Y);
}
/// It is safe to destroy a constant iff it is only used by constants itself.
@@ -185,4 +185,4 @@
: IsCompared(false), IsLoaded(false), StoredType(NotStored),
StoredOnceValue(nullptr), AccessingFunction(nullptr),
HasMultipleAccessingFunctions(false), HasNonInstructionUser(false),
- Ordering(NotAtomic) {}
+ Ordering(AtomicOrdering::NotAtomic) {}