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 ce45babdf042265b5448bcd345ae9cb35c85810b..538fa86a388e55812c491ce1b8679e17dd4d303c 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:
+      search_string = "vfpv3";

[Rodolph Perfetta, 2012/12/17 14:38:30]

The search_string variable is not used with VFP32DREGS since you have singled
out the case VFP32DREGS below.

[hans, 2012/12/17 15:32:46]

Done.

+      break;
     default:
       UNREACHABLE();
   }
 
+  if (feature == VFP32DREGS) {
+    return CPUInfoContainsString("vfpv3") && !CPUInfoContainsString("d16");

[Rodolph Perfetta, 2012/12/17 14:38:30]

I believe some early devices such as nexus one do not report vfpv3 but vfp (see
special case feature == VFP3 below).

Maybe something on the line of

if (ArmCpuHasFeature(VFP3) && !CPUInfoContainsString("d16"))

would work better.

[hans, 2012/12/17 15:32:46]

Done.

+  }
+
   if (CPUInfoContainsString(search_string)) {
     return true;
   }