[ARM] Replace processor check with feature

Add new feature, `FeatureUseWideStrideVFP`, that replaces the need for a
processor check.  Otherwise, NFC.

llvm-svn: 339354
diff --git a/llvm/lib/Target/ARM/ARMSubtarget.h b/llvm/lib/Target/ARM/ARMSubtarget.h
index 74aee9a..69bc3ea 100644
--- a/llvm/lib/Target/ARM/ARMSubtarget.h
+++ b/llvm/lib/Target/ARM/ARMSubtarget.h
@@ -353,6 +353,9 @@
   /// If true, loading into a D subregister will be penalized.
   bool SlowLoadDSubregister = false;
 
+  /// If true, use a wider stride when allocating VFP registers.
+  bool UseWideStrideVFP = false;
+
   /// If true, the AGU and NEON/FPU units are multiplexed.
   bool HasMuxedUnits = false;
 
@@ -596,6 +599,7 @@
   bool hasVMLxHazards() const { return HasVMLxHazards; }
   bool hasSlowOddRegister() const { return SlowOddRegister; }
   bool hasSlowLoadDSubregister() const { return SlowLoadDSubregister; }
+  bool useWideStrideVFP() const { return UseWideStrideVFP; }
   bool hasMuxedUnits() const { return HasMuxedUnits; }
   bool dontWidenVMOVS() const { return DontWidenVMOVS; }
   bool useSplatVFPToNeon() const { return SplatVFPToNeon; }