TailDuplicator: Use optForSize instead of hasFnAttribute.

This will cause minsize functions to have the same threshold as optsize
functions, but otherwise should have no effects.

llvm-svn: 278980
diff --git a/llvm/lib/CodeGen/TailDuplicator.cpp b/llvm/lib/CodeGen/TailDuplicator.cpp
index dd84cef..ec8e48d 100644
--- a/llvm/lib/CodeGen/TailDuplicator.cpp
+++ b/llvm/lib/CodeGen/TailDuplicator.cpp
@@ -513,7 +513,7 @@
   unsigned MaxDuplicateCount;
   if (TailDuplicateSize.getNumOccurrences() == 0 &&
       // FIXME: Use Function::optForSize().
-      MF.getFunction()->hasFnAttribute(Attribute::OptimizeForSize))
+      MF.getFunction()->optForSize())
     MaxDuplicateCount = 1;
   else
     MaxDuplicateCount = TailDuplicateSize;