X86: Canonicalize access to function attributes, NFC

Canonicalize access to function attributes to use the simpler API.

getAttributes().getAttribute(AttributeSet::FunctionIndex, Kind)
  => getFnAttribute(Kind)

getAttributes().hasAttribute(AttributeSet::FunctionIndex, Kind)
  => hasFnAttribute(Kind)

llvm-svn: 229214
diff --git a/llvm/lib/Target/X86/X86CallFrameOptimization.cpp b/llvm/lib/Target/X86/X86CallFrameOptimization.cpp
index 1ede5c7..d6563c2 100644
--- a/llvm/lib/Target/X86/X86CallFrameOptimization.cpp
+++ b/llvm/lib/Target/X86/X86CallFrameOptimization.cpp
@@ -163,11 +163,9 @@
     return true;
 
   // Don't do this when not optimizing for size.
-  AttributeSet FnAttrs = MF.getFunction()->getAttributes();
   bool OptForSize =
-      FnAttrs.hasAttribute(AttributeSet::FunctionIndex,
-                           Attribute::OptimizeForSize) ||
-      FnAttrs.hasAttribute(AttributeSet::FunctionIndex, Attribute::MinSize);
+      MF.getFunction()->hasFnAttribute(Attribute::OptimizeForSize) ||
+      MF.getFunction()->hasFnAttribute(Attribute::MinSize);
 
   if (!OptForSize)
     return false;