Clarified assert text.

llvm-svn: 147471
diff --git a/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp b/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
index 1e58173..9ee7c0b 100644
--- a/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -646,7 +646,7 @@
                                  SmallVectorImpl<MachineInstr*> *dead) {
   DEBUG(dbgs() << "Shrink: " << *li << '\n');
   assert(TargetRegisterInfo::isVirtualRegister(li->reg)
-         && "Can't only shrink physical registers");
+         && "Can only shrink virtual registers");
   // Find all the values used, including PHI kills.
   SmallVector<std::pair<SlotIndex, VNInfo*>, 16> WorkList;