avoid unnecessary direct access to LiveInterval::ranges

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190170 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/StrongPHIElimination.cpp b/lib/CodeGen/StrongPHIElimination.cpp
index d8b287f..79146eb 100644
--- a/lib/CodeGen/StrongPHIElimination.cpp
+++ b/lib/CodeGen/StrongPHIElimination.cpp
@@ -344,7 +344,7 @@
     LiveInterval &DestLI = LI->getInterval(DestReg);
     LiveInterval &NewLI = LI->getInterval(NewReg);
 
-    assert(DestLI.ranges.size() == 1
+    assert(DestLI.size() == 1
            && "PHI destination copy's live interval should be a single live "
                "range from the beginning of the BB to the copy instruction.");
     LiveRange *DestLR = DestLI.begin();