VM: Fix identical comparisons with bigints.

runtime/vm/stub_code_arm.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_ARM)
 
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
 #include "vm/compiler.h"
@@ skipping 2106 matching lines @@
   const Register temp = R2;
   const Register left = R1;
   const Register right = R0;
   __ ldr(left, Address(SP, 1 * kWordSize));
   __ ldr(right, Address(SP, 0 * kWordSize));
   GenerateIdenticalWithNumberCheckStub(assembler, left, right, temp);
   __ Ret();
 }
 
 
-// Called from otpimzied code only. Must preserve any registers that are
-// destroyed.
+// Called from optimized code only.
 // LR: return address.
 // SP + 4: left operand.
 // SP + 0: right operand.
 // Return Zero condition flag set if equal.
 void StubCode::GenerateOptimizedIdenticalWithNumberCheckStub(
     Assembler* assembler) {
   const Register temp = R2;
   const Register left = R1;
   const Register right = R0;
-  // Preserve left, right and temp.
-  __ PushList((1 << R0) | (1 << R1) | (1 << R2));
-  __ ldr(left, Address(SP, 4 * kWordSize));
-  __ ldr(right, Address(SP, 3 * kWordSize));
+  __ ldr(left, Address(SP, 1 * kWordSize));
+  __ ldr(right, Address(SP, 0 * kWordSize));
   GenerateIdenticalWithNumberCheckStub(assembler, left, right, temp);
-  __ PopList((1 << R0) | (1 << R1) | (1 << R2));
   __ Ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM