ARM: Make use of d16-d31 when available.

src/platform-linux.cc

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 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
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@@ skipping 138 matching lines @@
       break;
     case VFP3:
       search_string = "vfpv3";
       break;
     case ARMv7:
       search_string = "ARMv7";
       break;
     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;
   }
 
   if (feature == VFP3) {
     // Some old kernels will report vfp not vfpv3. Here we make a last attempt
     // to detect vfpv3 by checking for vfp *and* neon, since neon is only
     // available on architectures with vfpv3.
     // Checking neon on its own is not enough as it is possible to have neon
     // without vfp.
@@ skipping 1137 matching lines @@
 
 
 void Sampler::Stop() {
   ASSERT(IsActive());
   SignalSender::RemoveActiveSampler(this);
   SetActive(false);
 }
 
 
 } }  // namespace v8::internal