Clobber non-live temporaries on some paths involving a possible slow-path allocation.

runtime/vm/intermediate_language_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"  // Needed here to get TARGET_ARCH_ARM.
 #if defined(TARGET_ARCH_ARM)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/cpu.h"
@@ skipping 1935 matching lines @@
       default:
         UNREACHABLE();
         break;
     }
     if (can_pack_into_smi()) {
       __ SmiTag(result);
     } else {
       // If the value cannot fit in a smi then allocate a mint box for it.
       Register value = locs()->temp(0).reg();
       Register temp = locs()->temp(1).reg();
+      // Value register needs to be manually preserved on allocation slow-path.
+      locs()->live_registers()->Add(locs()->temp(0), kUnboxedInt32);
+
       ASSERT(result != value);
       __ MoveRegister(value, result);
       __ SmiTag(result);
 
       Label done;
       __ TestImmediate(value, 0xC0000000);
       __ b(&done, EQ);
       BoxAllocationSlowPath::Allocate(
           compiler, this, compiler->mint_class(), result, temp);
       __ eor(temp, temp, Operand(temp));
@@ skipping 160 matching lines @@
     __ b(&store_float64x2, EQ);
 
     // Fall through.
     __ b(&store_pointer);
 
     if (!compiler->is_optimizing()) {
         locs()->live_registers()->Add(locs()->in(0));
         locs()->live_registers()->Add(locs()->in(1));
     }
 
+    // Manually preserve temp which could be clobbered on the slow path.
+    locs()->live_registers()->Add(locs()->temp(0));
+
     {
       __ Bind(&store_double);
       EnsureMutableBox(compiler,
                        this,
                        temp,
                        compiler->double_class(),
                        instance_reg,
                        offset_in_bytes_,
                        temp2);
       __ CopyDoubleField(temp, value_reg, TMP, temp2, fpu_temp);
@@ skipping 4756 matching lines @@
   compiler->GenerateCall(token_pos(), &label, stub_kind_, locs());
 #if defined(DEBUG)
   __ LoadImmediate(R4, kInvalidObjectPointer);
   __ LoadImmediate(R5, kInvalidObjectPointer);
 #endif
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM