AsmMatcher: Ensure classes are totally ordered, so we can std::sort them reliably.

[oota-llvm.git] / utils / TableGen / AsmMatcherEmitter.cpp

diff --git a/utils/TableGen/AsmMatcherEmitter.cpp b/utils/TableGen/AsmMatcherEmitter.cpp
index 783c6b5aae9416e71b45763e1a9839f5c2ee658f..4ba3df11764dedc1749b43ed39f9129f34476775 100644 (file)
--- a/utils/TableGen/AsmMatcherEmitter.cpp
+++ b/utils/TableGen/AsmMatcherEmitter.cpp
@@ -388,6 +388,9 @@ public:
 
   /// operator< - Compare two classes.
   bool operator<(const ClassInfo &RHS) const {
+    if (this == &RHS)
+      return false;
+
     // Unrelated classes can be ordered by kind.
     if (!isRelatedTo(RHS))
       return Kind < RHS.Kind;
@@ -403,7 +406,13 @@ public:
 
     default:
       // This class preceeds the RHS if it is a proper subset of the RHS.
-      return this != &RHS && isSubsetOf(RHS);
+      if (isSubsetOf(RHS))
+       return true;
+      if (RHS.isSubsetOf(*this))
+       return false;
+
+      // Otherwise, order by name to ensure we have a total ordering.
+      return ValueName < RHS.ValueName;
     }
   }
 };