Encode a cost of zero as a cost of 1.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@27745 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/PerfectShuffle/PerfectShuffle.cpp b/utils/PerfectShuffle/PerfectShuffle.cpp
index c2abe9b..b19dd0d 100644
--- a/utils/PerfectShuffle/PerfectShuffle.cpp
+++ b/utils/PerfectShuffle/PerfectShuffle.cpp
@@ -381,7 +381,9 @@
     
     // CostSat - The cost of this operation saturated to two bits.
     unsigned CostSat = ShufTab[i].Cost;
-    if (CostSat > 3) CostSat = 3;
+    if (CostSat > 4) CostSat = 4;
+    if (CostSat == 0) CostSat = 1;
+    --CostSat;  // Cost is now between 0-3.
     
     unsigned OpNum = ShufTab[i].Op ? ShufTab[i].Op->OpNum : 0;
     assert(OpNum < 16 && "Too few bits to encode operation!");