From 368a4565034b907943f5c0173574eb47939b74bf Mon Sep 17 00:00:00 2001
From: Daniel Dunbar <daniel@zuster.org>
Date: Thu, 27 May 2010 05:31:32 +0000
Subject: [PATCH] AsmMatcher: Ensure classes are totally ordered, so we can
 std::sort them reliably.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104806 91177308-0d34-0410-b5e6-96231b3b80d8
---
 utils/TableGen/AsmMatcherEmitter.cpp | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/utils/TableGen/AsmMatcherEmitter.cpp b/utils/TableGen/AsmMatcherEmitter.cpp
index 783c6b5aae9..4ba3df11764 100644
--- 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;
     }
   }
 };