ARM: Make use of d16-d31 when available.

src/platform-linux.cc

Index: src/platform-linux.cc
diff --git a/src/platform-linux.cc b/src/platform-linux.cc
index e89d2cc9c8a861360fd3d704ae0baf650700d9f5..6c724bd016a2a6841cfb8a8065c25c89688f311e 100644
--- a/src/platform-linux.cc
+++ b/src/platform-linux.cc
@@ -156,10 +156,17 @@ bool OS::ArmCpuHasFeature(CpuFeature feature) {
     case SUDIV:
       search_string = "idiva";
       break;
+    case VFP32DREGS:
+      // This case is handled specially below.
+      break;
     default:
       UNREACHABLE();
   }
 
+  if (feature == VFP32DREGS) {
+    return ArmCpuHasFeature(VFP3) && !CPUInfoContainsString("d16");
+  }
+
   if (CPUInfoContainsString(search_string)) {
     return true;
   }