Properly emit _fltused with FastISel. Refactor to share code with SDAG.
Patch by Joe Groff!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151183 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86AsmPrinter.cpp b/lib/Target/X86/X86AsmPrinter.cpp
index c61ad72..268cbf4 100644
--- a/lib/Target/X86/X86AsmPrinter.cpp
+++ b/lib/Target/X86/X86AsmPrinter.cpp
@@ -600,7 +600,7 @@
   }
 
   if (Subtarget->isTargetWindows() && !Subtarget->isTargetCygMing() &&
-      MMI->callsExternalVAFunctionWithFloatingPointArguments()) {
+      MMI->usesVAFloatArgument()) {
     StringRef SymbolName = Subtarget->is64Bit() ? "_fltused" : "__fltused";
     MCSymbol *S = MMI->getContext().GetOrCreateSymbol(SymbolName);
     OutStreamer.EmitSymbolAttribute(S, MCSA_Global);