RegAllocFast: Rename statistic from NumCopies to NumCoalesced

The metric does not return the number of remaining (or inserted) copies
but the number of copies that were coalesced. Pick a more descriptive
name.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@346287 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/RegAllocFast.cpp

@@ -54,7 +54,7 @@ using namespace llvm;
 
 STATISTIC(NumStores, "Number of stores added");
 STATISTIC(NumLoads , "Number of loads added");
-STATISTIC(NumCopies, "Number of copies coalesced");
+STATISTIC(NumCoalesced, "Number of copies coalesced");
 
 static RegisterRegAlloc
   fastRegAlloc("fast", "fast register allocator", createFastRegisterAllocator);
@@ -1079,7 +1079,7 @@ void RegAllocFast::allocateBasicBlock(MachineBasicBlock &MBB) {
   // LiveVirtRegs might refer to the instrs.
   for (MachineInstr *MI : Coalesced)
     MBB.erase(MI);
-  NumCopies += Coalesced.size();
+  NumCoalesced += Coalesced.size();
 
   LLVM_DEBUG(MBB.dump());
 }