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/CodeGen/SelectionDAG/FastISel.cpp b/lib/CodeGen/SelectionDAG/FastISel.cpp
index dce3389..fd8ce78 100644
--- a/lib/CodeGen/SelectionDAG/FastISel.cpp
+++ b/lib/CodeGen/SelectionDAG/FastISel.cpp
@@ -561,6 +561,9 @@
     return true;
   }
 
+  MachineModuleInfo &MMI = FuncInfo.MF->getMMI();
+  ComputeUsesVAFloatArgument(*Call, &MMI);
+
   const Function *F = Call->getCalledFunction();
   if (!F) return false;