[IR] Refactor attribute methods in Function class (NFC)

Rename the functions that query the optimization kind attributes.

Differential revision: https://reviews.llvm.org/D60287

llvm-svn: 357731
diff --git a/llvm/lib/Transforms/Scalar/WarnMissedTransforms.cpp b/llvm/lib/Transforms/Scalar/WarnMissedTransforms.cpp
index bcb877a..707adf4 100644
--- a/llvm/lib/Transforms/Scalar/WarnMissedTransforms.cpp
+++ b/llvm/lib/Transforms/Scalar/WarnMissedTransforms.cpp
@@ -92,7 +92,7 @@
 WarnMissedTransformationsPass::run(Function &F, FunctionAnalysisManager &AM) {
   // Do not warn about not applied transformations if optimizations are
   // disabled.
-  if (F.optForNone())
+  if (F.hasOptNone())
     return PreservedAnalyses::all();
 
   auto &ORE = AM.getResult<OptimizationRemarkEmitterAnalysis>(F);