[driver] Create a new -mfpmath= option, which is used to control whether clang
uses Neon instructions for single-precision FP.

-mfpmath=neon is analogous to passing llc -mattr=+neonfp.
-mfpmath=[vfp|vfp2|vfp3|vfp4] is analogous to passing llc -mattr=-neonfp.

rdar://11108618


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@154046 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Basic/Targets.cpp b/lib/Basic/Targets.cpp
index 1fcef33..26fdca2 100644
--- a/lib/Basic/Targets.cpp
+++ b/lib/Basic/Targets.cpp
@@ -2730,7 +2730,8 @@
                                  StringRef Name,
                                  bool Enabled) const {
     if (Name == "soft-float" || Name == "soft-float-abi" ||
-        Name == "vfp2" || Name == "vfp3" || Name == "neon" || Name == "d16") {
+        Name == "vfp2" || Name == "vfp3" || Name == "neon" || Name == "d16" ||
+        Name == "neonfp") {
       Features[Name] = Enabled;
     } else
       return false;