From d0f6f017319bbc32b57c2e574d774ac91fe20f18 Mon Sep 17 00:00:00 2001
From: Lang Hames <lhames@gmail.com>
Date: Sat, 17 Jul 2010 06:31:41 +0000
Subject: [PATCH] Iterating over sets of pointers in a heuristic was a bad
 idea. Switching any command line paramater changed the register allocation
 produced by PBQP.

Turns out variety is not the spice of life.

Fixed some comparators, added others. All good now.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108613 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/PBQP/Heuristics/Briggs.h |  8 ++------
 lib/CodeGen/RegAllocPBQP.cpp         | 12 ++++++++++--
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/lib/CodeGen/PBQP/Heuristics/Briggs.h b/lib/CodeGen/PBQP/Heuristics/Briggs.h
index 4c1ce119ed0..18eaf7c0da9 100644
--- a/lib/CodeGen/PBQP/Heuristics/Briggs.h
+++ b/lib/CodeGen/PBQP/Heuristics/Briggs.h
@@ -52,9 +52,7 @@ namespace PBQP {
         bool operator()(Graph::NodeItr n1Itr, Graph::NodeItr n2Itr) const {
           if (s->getSolverDegree(n1Itr) > s->getSolverDegree(n2Itr))
             return true;
-          if (s->getSolverDegree(n1Itr) < s->getSolverDegree(n2Itr))
-            return false;
-          return (&*n1Itr < &*n2Itr);
+          return false;
         }
       private:
         HeuristicSolverImpl<Briggs> *s;
@@ -69,9 +67,7 @@ namespace PBQP {
                   cost2 = g->getNodeCosts(n2Itr)[0] / s->getSolverDegree(n2Itr);
           if (cost1 < cost2)
             return true;
-          if (cost1 > cost2)
-            return false;
-          return (&*n1Itr < &*n2Itr);
+          return false;
         }
 
       private:
diff --git a/lib/CodeGen/RegAllocPBQP.cpp b/lib/CodeGen/RegAllocPBQP.cpp
index 45104b48fe4..a7ea8e7c3ad 100644
--- a/lib/CodeGen/RegAllocPBQP.cpp
+++ b/lib/CodeGen/RegAllocPBQP.cpp
@@ -104,7 +104,15 @@ namespace {
     virtual bool runOnMachineFunction(MachineFunction &MF);
 
   private:
-    typedef std::map<const LiveInterval*, unsigned> LI2NodeMap;
+
+    class LIOrdering {
+    public:
+      bool operator()(const LiveInterval *li1, const LiveInterval *li2) const {
+        return li1->reg < li2->reg;
+      }
+    };
+
+    typedef std::map<const LiveInterval*, unsigned, LIOrdering> LI2NodeMap;
     typedef std::vector<const LiveInterval*> Node2LIMap;
     typedef std::vector<unsigned> AllowedSet;
     typedef std::vector<AllowedSet> AllowedSetMap;
@@ -112,7 +120,7 @@ namespace {
     typedef std::pair<unsigned, unsigned> RegPair;
     typedef std::map<RegPair, PBQP::PBQPNum> CoalesceMap;
 
-    typedef std::set<LiveInterval*> LiveIntervalSet;
+    typedef std::set<LiveInterval*, LIOrdering> LiveIntervalSet;
 
     typedef std::vector<PBQP::Graph::NodeItr> NodeVector;
 
-- 
2.11.0