Use convenience function for consistency.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150457 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index 64bbf1e..72f4eb7 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -994,8 +994,7 @@
     if (Reg == 0 || Reg == li.reg)
       continue;
 
-    if (TargetRegisterInfo::isPhysicalRegister(Reg) &&
-        !allocatableRegs_[Reg])
+    if (TargetRegisterInfo::isPhysicalRegister(Reg) && !isAllocatable(Reg))
       continue;
     RegOp = MO.getReg();
     break; // Found vreg operand - leave the loop.