ARM: add cyclone CPU with ZeroCycleZeroing feature.

The Cyclone CPU is similar to swift for most LLVM purposes, but does have two
preferred instructions for zeroing a VFP register. This teaches LLVM about
them.

llvm-svn: 205309
diff --git a/llvm/lib/Target/ARM/ARMSubtarget.h b/llvm/lib/Target/ARM/ARMSubtarget.h
index 2ce99c8..e76cc85 100644
--- a/llvm/lib/Target/ARM/ARMSubtarget.h
+++ b/llvm/lib/Target/ARM/ARMSubtarget.h
@@ -177,6 +177,10 @@
   /// HasCRC - if true, processor supports CRC instructions
   bool HasCRC;
 
+  /// If true, the instructions "vmov.i32 d0, #0" and "vmov.i32 q0, #0" are
+  /// particularly effective at zeroing a VFP register.
+  bool HasZeroCycleZeroing;
+
   /// AllowsUnalignedMem - If true, the subtarget allows unaligned memory
   /// accesses for some types.  For details, see
   /// ARMTargetLowering::allowsUnalignedMemoryAccesses().
@@ -298,6 +302,7 @@
   bool isFPOnlySP() const { return FPOnlySP; }
   bool hasPerfMon() const { return HasPerfMon; }
   bool hasTrustZone() const { return HasTrustZone; }
+  bool hasZeroCycleZeroing() const { return HasZeroCycleZeroing; }
   bool prefers32BitThumb() const { return Pref32BitThumb; }
   bool avoidCPSRPartialUpdate() const { return AvoidCPSRPartialUpdate; }
   bool avoidMOVsShifterOperand() const { return AvoidMOVsShifterOperand; }