Also compute interference intervals for blocks with no uses.

When the live range is live through a block that doesn't use the register, but
that has interference, region splitting wants to split at the top and bottom of
the basic block.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124839 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/RegAllocGreedy.cpp b/lib/CodeGen/RegAllocGreedy.cpp
index 92f97d0..2c772a2 100644
--- a/lib/CodeGen/RegAllocGreedy.cpp
+++ b/lib/CodeGen/RegAllocGreedy.cpp
@@ -611,9 +611,7 @@
     if (!IntI.valid())
       continue;
     for (unsigned i = 0, e = LiveBlocks.size(); i != e; ++i) {
-      BlockInfo &BI = LiveBlocks[i];
-      if (!BI.Uses)
-        continue;
+      const BlockInfo &BI = LiveBlocks[i];
       IndexPair &IP = InterferenceRanges[i];
       SlotIndex Start, Stop;
       tie(Start, Stop) = Indexes->getMBBRange(BI.MBB);