Remove scratch register requirement from LoadInstanceDescriptors on arm and mips.

src/arm/full-codegen-arm.cc

 // Copyright 2012 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 1119 matching lines @@
   __ b(ne, &fixed_array);
 
   // We got a map in register r0. Get the enumeration cache from it.
   Label no_descriptors;
   __ bind(&use_cache);
 
   __ EnumLength(r1, r0);
   __ cmp(r1, Operand(Smi::FromInt(0)));
   __ b(eq, &no_descriptors);
 
-  __ LoadInstanceDescriptors(r0, r2, r4);
+  __ LoadInstanceDescriptors(r0, r2);
   __ ldr(r2, FieldMemOperand(r2, DescriptorArray::kEnumCacheOffset));
   __ ldr(r2, FieldMemOperand(r2, DescriptorArray::kEnumCacheBridgeCacheOffset));
 
   // Set up the four remaining stack slots.
   __ push(r0);  // Map.
   __ mov(r0, Operand(Smi::FromInt(0)));
   // Push enumeration cache, enumeration cache length (as smi) and zero.
   __ Push(r2, r1, r0);
   __ jmp(&loop);
 
@@ skipping 1525 matching lines @@
   // Look for valueOf symbol in the descriptor array, and indicate false if
   // found. Since we omit an enumeration index check, if it is added via a
   // transition that shares its descriptor array, this is a false positive.
   Label entry, loop, done;
 
   // Skip loop if no descriptors are valid.
   __ NumberOfOwnDescriptors(r3, r1);
   __ cmp(r3, Operand(0));
   __ b(eq, &done);
 
-  __ LoadInstanceDescriptors(r1, r4, r2);
+  __ LoadInstanceDescriptors(r1, r4);
   // r4: descriptor array.
   // r3: valid entries in the descriptor array.
   STATIC_ASSERT(kSmiTag == 0);
   STATIC_ASSERT(kSmiTagSize == 1);
   STATIC_ASSERT(kPointerSize == 4);
   __ mov(ip, Operand(DescriptorArray::kDescriptorSize));
   __ mul(r3, r3, ip);
   // Calculate location of the first key name.
   __ add(r4, r4, Operand(DescriptorArray::kFirstOffset - kHeapObjectTag));
   // Calculate the end of the descriptor array.
@@ skipping 1831 matching lines @@
   *context_length = 0;
   return previous_;
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM