fix minsize detection: minsize attribute implies optimizing for size

llvm-svn: 244499
diff --git a/llvm/lib/Target/X86/X86InstrInfo.cpp b/llvm/lib/Target/X86/X86InstrInfo.cpp
index c37f5c8..d65c2d7 100644
--- a/llvm/lib/Target/X86/X86InstrInfo.cpp
+++ b/llvm/lib/Target/X86/X86InstrInfo.cpp
@@ -5347,11 +5347,8 @@
   // Check switch flag
   if (NoFusing) return nullptr;
 
-  // Unless optimizing for size, don't fold to avoid partial
-  // register update stalls
-  // FIXME: Use Function::optForSize().
-  if (!MF.getFunction()->hasFnAttribute(Attribute::OptimizeForSize) &&
-      hasPartialRegUpdate(MI->getOpcode()))
+  // Avoid partial register update stalls unless optimizing for size.
+  if (!MF.getFunction()->optForSize() && hasPartialRegUpdate(MI->getOpcode()))
     return nullptr;
 
   // Determine the alignment of the load.