Very small optimization of ARM compare stub.

src/arm/simulator-arm.cc

 // Copyright 2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 872 matching lines @@
     overflow = ((left < 0 && right >= 0) || (left >= 0 && right < 0))
                // and first operand and result have different signs
                && ((left < 0 && alu_out >= 0) || (left >= 0 && alu_out < 0));
   }
   return overflow;
 }
 
 
 // Support for VFP comparisons.
 void Simulator::Compute_FPSCR_Flags(double val1, double val2) {
+  if (isnan(val1) || isnan(val2)) {
+    n_flag_FPSCR_ = false;
+    z_flag_FPSCR_ = false;
+    c_flag_FPSCR_ = true;
+    v_flag_FPSCR_ = true;
   // All non-NaN cases.
-  if (val1 == val2) {
+  } else if (val1 == val2) {
     n_flag_FPSCR_ = false;
     z_flag_FPSCR_ = true;
     c_flag_FPSCR_ = true;
     v_flag_FPSCR_ = false;
   } else if (val1 < val2) {
     n_flag_FPSCR_ = true;
     z_flag_FPSCR_ = false;
     c_flag_FPSCR_ = false;
     v_flag_FPSCR_ = false;
   } else {
@@ skipping 1350 matching lines @@
   uintptr_t* stack_slot = reinterpret_cast<uintptr_t*>(current_sp);
   uintptr_t address = *stack_slot;
   set_register(sp, current_sp + sizeof(uintptr_t));
   return address;
 }
 
 
 } }  // namespace assembler::arm
 
 #endif  // !defined(__arm__)