Fix -O0 compilation errors

runtime/vm/intermediate_language_mips.cc

Index: runtime/vm/intermediate_language_mips.cc
diff --git a/runtime/vm/intermediate_language_mips.cc b/runtime/vm/intermediate_language_mips.cc
index 612d97e4f4b42406adc129511a5e72db629045ad..c30aa13b15b509940f07d33df789a8e2802689bc 100644
--- a/runtime/vm/intermediate_language_mips.cc
+++ b/runtime/vm/intermediate_language_mips.cc
@@ -1779,6 +1779,7 @@ LocationSummary* GuardFieldLengthInstr::MakeLocationSummary(Zone* zone,
     return summary;
   }
   UNREACHABLE();

[Florian Schneider, 2016/08/29 21:44:06]

I wonder if removing the UNREACHABLE would also fix it. It does not make sense
anyway after the else-clause.

Or even remove the else-clause as well, and write instead:

if (...) {
  ...
  return x;
}
...
return y;

[zra, 2016/08/29 21:57:30]

removed else

+  return NULL;
 }