RegisterPressure heuristics currently require signed comparisons.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178823 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineScheduler.cpp b/lib/CodeGen/MachineScheduler.cpp
index ed6b986..5bd2349 100644
--- a/lib/CodeGen/MachineScheduler.cpp
+++ b/lib/CodeGen/MachineScheduler.cpp
@@ -1660,7 +1660,7 @@
 }
 
 /// Return true if this heuristic determines order.
-static bool tryLess(unsigned TryVal, unsigned CandVal,
+static bool tryLess(int TryVal, int CandVal,
                     ConvergingScheduler::SchedCandidate &TryCand,
                     ConvergingScheduler::SchedCandidate &Cand,
                     ConvergingScheduler::CandReason Reason) {
@@ -1676,7 +1676,7 @@
   return false;
 }
 
-static bool tryGreater(unsigned TryVal, unsigned CandVal,
+static bool tryGreater(int TryVal, int CandVal,
                        ConvergingScheduler::SchedCandidate &TryCand,
                        ConvergingScheduler::SchedCandidate &Cand,
                        ConvergingScheduler::CandReason Reason) {